+ GNU GENERAL PUBLIC LICENSE

+ Version 3, 29 June 2007

+

+ Copyright (C) 2020 Ava Labs.

+ Everyone is permitted to copy and distribute verbatim copies

+ of this license document, but changing it is not allowed.

+

+ Preamble

+

+ The GNU General Public License is a free, copyleft license for

+software and other kinds of works.

+

+ The licenses for most software and other practical works are designed

+to take away your freedom to share and change the works. By contrast,

+the GNU General Public License is intended to guarantee your freedom to

+share and change all versions of a program--to make sure it remains free

+software for all its users. We, the Free Software Foundation, use the

+GNU General Public License for most of our software; it applies also to

+any other work released this way by its authors. You can apply it to

+your programs, too.

+

+ When we speak of free software, we are referring to freedom, not

+price. Our General Public Licenses are designed to make sure that you

+have the freedom to distribute copies of free software (and charge for

+them if you wish), that you receive source code or can get it if you

+want it, that you can change the software or use pieces of it in new

+free programs, and that you know you can do these things.

+

+ To protect your rights, we need to prevent others from denying you

+these rights or asking you to surrender the rights. Therefore, you have

+certain responsibilities if you distribute copies of the software, or if

+you modify it: responsibilities to respect the freedom of others.

+

+ For example, if you distribute copies of such a program, whether

+gratis or for a fee, you must pass on to the recipients the same

+freedoms that you received. You must make sure that they, too, receive

+or can get the source code. And you must show them these terms so they

+know their rights.

+

+ Developers that use the GNU GPL protect your rights with two steps:

+(1) assert copyright on the software, and (2) offer you this License

+giving you legal permission to copy, distribute and/or modify it.

+

+ For the developers' and authors' protection, the GPL clearly explains

+that there is no warranty for this free software. For both users' and

+authors' sake, the GPL requires that modified versions be marked as

+changed, so that their problems will not be attributed erroneously to

+authors of previous versions.

+

+ Some devices are designed to deny users access to install or run

+modified versions of the software inside them, although the manufacturer

+can do so. This is fundamentally incompatible with the aim of

+protecting users' freedom to change the software. The systematic

+pattern of such abuse occurs in the area of products for individuals to

+use, which is precisely where it is most unacceptable. Therefore, we

+have designed this version of the GPL to prohibit the practice for those

+products. If such problems arise substantially in other domains, we

+stand ready to extend this provision to those domains in future versions

+of the GPL, as needed to protect the freedom of users.

+

+ Finally, every program is threatened constantly by software patents.

+States should not allow patents to restrict development and use of

+software on general-purpose computers, but in those that do, we wish to

+avoid the special danger that patents applied to a free program could

+make it effectively proprietary. To prevent this, the GPL assures that

+patents cannot be used to render the program non-free.

+

+ The precise terms and conditions for copying, distribution and

+modification follow.

+

+ TERMS AND CONDITIONS

+

+ 0. Definitions.

+

+ "This License" refers to version 3 of the GNU General Public License.

+

+ "Copyright" also means copyright-like laws that apply to other kinds of

+works, such as semiconductor masks.

+

+ "The Program" refers to any copyrightable work licensed under this

+License. Each licensee is addressed as "you". "Licensees" and

+"recipients" may be individuals or organizations.

+

+ To "modify" a work means to copy from or adapt all or part of the work

+in a fashion requiring copyright permission, other than the making of an

+exact copy. The resulting work is called a "modified version" of the

+earlier work or a work "based on" the earlier work.

+

+ A "covered work" means either the unmodified Program or a work based

+on the Program.

+

+ To "propagate" a work means to do anything with it that, without

+permission, would make you directly or secondarily liable for

+infringement under applicable copyright law, except executing it on a

+computer or modifying a private copy. Propagation includes copying,

+distribution (with or without modification), making available to the

+public, and in some countries other activities as well.

+

+ To "convey" a work means any kind of propagation that enables other

+parties to make or receive copies. Mere interaction with a user through

+a computer network, with no transfer of a copy, is not conveying.

+

+ An interactive user interface displays "Appropriate Legal Notices"

+to the extent that it includes a convenient and prominently visible

+feature that (1) displays an appropriate copyright notice, and (2)

+tells the user that there is no warranty for the work (except to the

+extent that warranties are provided), that licensees may convey the

+work under this License, and how to view a copy of this License. If

+the interface presents a list of user commands or options, such as a

+menu, a prominent item in the list meets this criterion.

+

+ 1. Source Code.

+

+ The "source code" for a work means the preferred form of the work

+for making modifications to it. "Object code" means any non-source

+form of a work.

+

+ A "Standard Interface" means an interface that either is an official

+standard defined by a recognized standards body, or, in the case of

+interfaces specified for a particular programming language, one that

+is widely used among developers working in that language.

+

+ The "System Libraries" of an executable work include anything, other

+than the work as a whole, that (a) is included in the normal form of

+packaging a Major Component, but which is not part of that Major

+Component, and (b) serves only to enable use of the work with that

+Major Component, or to implement a Standard Interface for which an

+implementation is available to the public in source code form. A

+"Major Component", in this context, means a major essential component

+(kernel, window system, and so on) of the specific operating system

+(if any) on which the executable work runs, or a compiler used to

+produce the work, or an object code interpreter used to run it.

+

+ The "Corresponding Source" for a work in object code form means all

+the source code needed to generate, install, and (for an executable

+work) run the object code and to modify the work, including scripts to

+control those activities. However, it does not include the work's

+System Libraries, or general-purpose tools or generally available free

+programs which are used unmodified in performing those activities but

+which are not part of the work. For example, Corresponding Source

+includes interface definition files associated with source files for

+the work, and the source code for shared libraries and dynamically

+linked subprograms that the work is specifically designed to require,

+such as by intimate data communication or control flow between those

+subprograms and other parts of the work.

+

+ The Corresponding Source need not include anything that users

+can regenerate automatically from other parts of the Corresponding

+Source.

+

+ The Corresponding Source for a work in source code form is that

+same work.

+

+ 2. Basic Permissions.

+

+ All rights granted under this License are granted for the term of

+copyright on the Program, and are irrevocable provided the stated

+conditions are met. This License explicitly affirms your unlimited

+permission to run the unmodified Program. The output from running a

+covered work is covered by this License only if the output, given its

+content, constitutes a covered work. This License acknowledges your

+rights of fair use or other equivalent, as provided by copyright law.

+

+ You may make, run and propagate covered works that you do not

+convey, without conditions so long as your license otherwise remains

+in force. You may convey covered works to others for the sole purpose

+of having them make modifications exclusively for you, or provide you

+with facilities for running those works, provided that you comply with

+the terms of this License in conveying all material for which you do

+not control copyright. Those thus making or running the covered works

+for you must do so exclusively on your behalf, under your direction

+and control, on terms that prohibit them from making any copies of

+your copyrighted material outside their relationship with you.

+

+ Conveying under any other circumstances is permitted solely under

+the conditions stated below. Sublicensing is not allowed; section 10

+makes it unnecessary.

+

+ 3. Protecting Users' Legal Rights From Anti-Circumvention Law.

+

+ No covered work shall be deemed part of an effective technological

+measure under any applicable law fulfilling obligations under article

+11 of the WIPO copyright treaty adopted on 20 December 1996, or

+similar laws prohibiting or restricting circumvention of such

+measures.

+

+ When you convey a covered work, you waive any legal power to forbid

+circumvention of technological measures to the extent such circumvention

+is effected by exercising rights under this License with respect to

+the covered work, and you disclaim any intention to limit operation or

+modification of the work as a means of enforcing, against the work's

+users, your or third parties' legal rights to forbid circumvention of

+technological measures.

+

+ 4. Conveying Verbatim Copies.

+

+ You may convey verbatim copies of the Program's source code as you

+receive it, in any medium, provided that you conspicuously and

+appropriately publish on each copy an appropriate copyright notice;

+keep intact all notices stating that this License and any

+non-permissive terms added in accord with section 7 apply to the code;

+keep intact all notices of the absence of any warranty; and give all

+recipients a copy of this License along with the Program.

+

+ You may charge any price or no price for each copy that you convey,

+and you may offer support or warranty protection for a fee.

+

+ 5. Conveying Modified Source Versions.

+

+ You may convey a work based on the Program, or the modifications to

+produce it from the Program, in the form of source code under the

+terms of section 4, provided that you also meet all of these conditions:

+

+ a) The work must carry prominent notices stating that you modified

+ it, and giving a relevant date.

+

+ b) The work must carry prominent notices stating that it is

+ released under this License and any conditions added under section

+ 7. This requirement modifies the requirement in section 4 to

+ "keep intact all notices".

+

+ c) You must license the entire work, as a whole, under this

+ License to anyone who comes into possession of a copy. This

+ License will therefore apply, along with any applicable section 7

+ additional terms, to the whole of the work, and all its parts,

+ regardless of how they are packaged. This License gives no

+ permission to license the work in any other way, but it does not

+ invalidate such permission if you have separately received it.

+

+ d) If the work has interactive user interfaces, each must display

+ Appropriate Legal Notices; however, if the Program has interactive

+ interfaces that do not display Appropriate Legal Notices, your

+ work need not make them do so.

+

+ A compilation of a covered work with other separate and independent

+works, which are not by their nature extensions of the covered work,

+and which are not combined with it such as to form a larger program,

+in or on a volume of a storage or distribution medium, is called an

+"aggregate" if the compilation and its resulting copyright are not

+used to limit the access or legal rights of the compilation's users

+beyond what the individual works permit. Inclusion of a covered work

+in an aggregate does not cause this License to apply to the other

+parts of the aggregate.

+

+ 6. Conveying Non-Source Forms.

+

+ You may convey a covered work in object code form under the terms

+of sections 4 and 5, provided that you also convey the

+machine-readable Corresponding Source under the terms of this License,

+in one of these ways:

+

+ a) Convey the object code in, or embodied in, a physical product

+ (including a physical distribution medium), accompanied by the

+ Corresponding Source fixed on a durable physical medium

+ customarily used for software interchange.

+

+ b) Convey the object code in, or embodied in, a physical product

+ (including a physical distribution medium), accompanied by a

+ written offer, valid for at least three years and valid for as

+ long as you offer spare parts or customer support for that product

+ model, to give anyone who possesses the object code either (1) a

+ copy of the Corresponding Source for all the software in the

+ product that is covered by this License, on a durable physical

+ medium customarily used for software interchange, for a price no

+ more than your reasonable cost of physically performing this

+ conveying of source, or (2) access to copy the

+ Corresponding Source from a network server at no charge.

+

+ c) Convey individual copies of the object code with a copy of the

+ written offer to provide the Corresponding Source. This

+ alternative is allowed only occasionally and noncommercially, and

+ only if you received the object code with such an offer, in accord

+ with subsection 6b.

+

+ d) Convey the object code by offering access from a designated

+ place (gratis or for a charge), and offer equivalent access to the

+ Corresponding Source in the same way through the same place at no

+ further charge. You need not require recipients to copy the

+ Corresponding Source along with the object code. If the place to

+ copy the object code is a network server, the Corresponding Source

+ may be on a different server (operated by you or a third party)

+ that supports equivalent copying facilities, provided you maintain

+ clear directions next to the object code saying where to find the

+ Corresponding Source. Regardless of what server hosts the

+ Corresponding Source, you remain obligated to ensure that it is

+ available for as long as needed to satisfy these requirements.

+

+ e) Convey the object code using peer-to-peer transmission, provided

+ you inform other peers where the object code and Corresponding

+ Source of the work are being offered to the general public at no

+ charge under subsection 6d.

+

+ A separable portion of the object code, whose source code is excluded

+from the Corresponding Source as a System Library, need not be

+included in conveying the object code work.

+

+ A "User Product" is either (1) a "consumer product", which means any

+tangible personal property which is normally used for personal, family,

+or household purposes, or (2) anything designed or sold for incorporation

+into a dwelling. In determining whether a product is a consumer product,

+doubtful cases shall be resolved in favor of coverage. For a particular

+product received by a particular user, "normally used" refers to a

+typical or common use of that class of product, regardless of the status

+of the particular user or of the way in which the particular user

+actually uses, or expects or is expected to use, the product. A product

+is a consumer product regardless of whether the product has substantial

+commercial, industrial or non-consumer uses, unless such uses represent

+the only significant mode of use of the product.

+

+ "Installation Information" for a User Product means any methods,

+procedures, authorization keys, or other information required to install

+and execute modified versions of a covered work in that User Product from

+a modified version of its Corresponding Source. The information must

+suffice to ensure that the continued functioning of the modified object

+code is in no case prevented or interfered with solely because

+modification has been made.

+

+ If you convey an object code work under this section in, or with, or

+specifically for use in, a User Product, and the conveying occurs as

+part of a transaction in which the right of possession and use of the

+User Product is transferred to the recipient in perpetuity or for a

+fixed term (regardless of how the transaction is characterized), the

+Corresponding Source conveyed under this section must be accompanied

+by the Installation Information. But this requirement does not apply

+if neither you nor any third party retains the ability to install

+modified object code on the User Product (for example, the work has

+been installed in ROM).

+

+ The requirement to provide Installation Information does not include a

+requirement to continue to provide support service, warranty, or updates

+for a work that has been modified or installed by the recipient, or for

+the User Product in which it has been modified or installed. Access to a

+network may be denied when the modification itself materially and

+adversely affects the operation of the network or violates the rules and

+protocols for communication across the network.

+

+ Corresponding Source conveyed, and Installation Information provided,

+in accord with this section must be in a format that is publicly

+documented (and with an implementation available to the public in

+source code form), and must require no special password or key for

+unpacking, reading or copying.

+

+ 7. Additional Terms.

+

+ "Additional permissions" are terms that supplement the terms of this

+License by making exceptions from one or more of its conditions.

+Additional permissions that are applicable to the entire Program shall

+be treated as though they were included in this License, to the extent

+that they are valid under applicable law. If additional permissions

+apply only to part of the Program, that part may be used separately

+under those permissions, but the entire Program remains governed by

+this License without regard to the additional permissions.

+

+ When you convey a copy of a covered work, you may at your option

+remove any additional permissions from that copy, or from any part of

+it. (Additional permissions may be written to require their own

+removal in certain cases when you modify the work.) You may place

+additional permissions on material, added by you to a covered work,

+for which you have or can give appropriate copyright permission.

+

+ Notwithstanding any other provision of this License, for material you

+add to a covered work, you may (if authorized by the copyright holders of

+that material) supplement the terms of this License with terms:

+

+ a) Disclaiming warranty or limiting liability differently from the

+ terms of sections 15 and 16 of this License; or

+

+ b) Requiring preservation of specified reasonable legal notices or

+ author attributions in that material or in the Appropriate Legal

+ Notices displayed by works containing it; or

+

+ c) Prohibiting misrepresentation of the origin of that material, or

+ requiring that modified versions of such material be marked in

+ reasonable ways as different from the original version; or

+

+ d) Limiting the use for publicity purposes of names of licensors or

+ authors of the material; or

+

+ e) Declining to grant rights under trademark law for use of some

+ trade names, trademarks, or service marks; or

+

+ f) Requiring indemnification of licensors and authors of that

+ material by anyone who conveys the material (or modified versions of

+ it) with contractual assumptions of liability to the recipient, for

+ any liability that these contractual assumptions directly impose on

+ those licensors and authors.

+

+ All other non-permissive additional terms are considered "further

+restrictions" within the meaning of section 10. If the Program as you

+received it, or any part of it, contains a notice stating that it is

+governed by this License along with a term that is a further

+restriction, you may remove that term. If a license document contains

+a further restriction but permits relicensing or conveying under this

+License, you may add to a covered work material governed by the terms

+of that license document, provided that the further restriction does

+not survive such relicensing or conveying.

+

+ If you add terms to a covered work in accord with this section, you

+must place, in the relevant source files, a statement of the

+additional terms that apply to those files, or a notice indicating

+where to find the applicable terms.

+

+ Additional terms, permissive or non-permissive, may be stated in the

+form of a separately written license, or stated as exceptions;

+the above requirements apply either way.

+

+ 8. Termination.

+

+ You may not propagate or modify a covered work except as expressly

+provided under this License. Any attempt otherwise to propagate or

+modify it is void, and will automatically terminate your rights under

+this License (including any patent licenses granted under the third

+paragraph of section 11).

+

+ However, if you cease all violation of this License, then your

+license from a particular copyright holder is reinstated (a)

+provisionally, unless and until the copyright holder explicitly and

+finally terminates your license, and (b) permanently, if the copyright

+holder fails to notify you of the violation by some reasonable means

+prior to 60 days after the cessation.

+

+ Moreover, your license from a particular copyright holder is

+reinstated permanently if the copyright holder notifies you of the

+violation by some reasonable means, this is the first time you have

+received notice of violation of this License (for any work) from that

+copyright holder, and you cure the violation prior to 30 days after

+your receipt of the notice.

+

+ Termination of your rights under this section does not terminate the

+licenses of parties who have received copies or rights from you under

+this License. If your rights have been terminated and not permanently

+reinstated, you do not qualify to receive new licenses for the same

+material under section 10.

+

+ 9. Acceptance Not Required for Having Copies.

+

+ You are not required to accept this License in order to receive or

+run a copy of the Program. Ancillary propagation of a covered work

+occurring solely as a consequence of using peer-to-peer transmission

+to receive a copy likewise does not require acceptance. However,

+nothing other than this License grants you permission to propagate or

+modify any covered work. These actions infringe copyright if you do

+not accept this License. Therefore, by modifying or propagating a

+covered work, you indicate your acceptance of this License to do so.

+

+ 10. Automatic Licensing of Downstream Recipients.

+

+ Each time you convey a covered work, the recipient automatically

+receives a license from the original licensors, to run, modify and

+propagate that work, subject to this License. You are not responsible

+for enforcing compliance by third parties with this License.

+

+ An "entity transaction" is a transaction transferring control of an

+organization, or substantially all assets of one, or subdividing an

+organization, or merging organizations. If propagation of a covered

+work results from an entity transaction, each party to that

+transaction who receives a copy of the work also receives whatever

+licenses to the work the party's predecessor in interest had or could

+give under the previous paragraph, plus a right to possession of the

+Corresponding Source of the work from the predecessor in interest, if

+the predecessor has it or can get it with reasonable efforts.

+

+ You may not impose any further restrictions on the exercise of the

+rights granted or affirmed under this License. For example, you may

+not impose a license fee, royalty, or other charge for exercise of

+rights granted under this License, and you may not initiate litigation

+(including a cross-claim or counterclaim in a lawsuit) alleging that

+any patent claim is infringed by making, using, selling, offering for

+sale, or importing the Program or any portion of it.

+

+ 11. Patents.

+

+ A "contributor" is a copyright holder who authorizes use under this

+License of the Program or a work on which the Program is based. The

+work thus licensed is called the contributor's "contributor version".

+

+ A contributor's "essential patent claims" are all patent claims

+owned or controlled by the contributor, whether already acquired or

+hereafter acquired, that would be infringed by some manner, permitted

+by this License, of making, using, or selling its contributor version,

+but do not include claims that would be infringed only as a

+consequence of further modification of the contributor version. For

+purposes of this definition, "control" includes the right to grant

+patent sublicenses in a manner consistent with the requirements of

+this License.

+

+ Each contributor grants you a non-exclusive, worldwide, royalty-free

+patent license under the contributor's essential patent claims, to

+make, use, sell, offer for sale, import and otherwise run, modify and

+propagate the contents of its contributor version.

+

+ In the following three paragraphs, a "patent license" is any express

+agreement or commitment, however denominated, not to enforce a patent

+(such as an express permission to practice a patent or covenant not to

+sue for patent infringement). To "grant" such a patent license to a

+party means to make such an agreement or commitment not to enforce a

+patent against the party.

+

+ If you convey a covered work, knowingly relying on a patent license,

+and the Corresponding Source of the work is not available for anyone

+to copy, free of charge and under the terms of this License, through a

+publicly available network server or other readily accessible means,

+then you must either (1) cause the Corresponding Source to be so

+available, or (2) arrange to deprive yourself of the benefit of the

+patent license for this particular work, or (3) arrange, in a manner

+consistent with the requirements of this License, to extend the patent

+license to downstream recipients. "Knowingly relying" means you have

+actual knowledge that, but for the patent license, your conveying the

+covered work in a country, or your recipient's use of the covered work

+in a country, would infringe one or more identifiable patents in that

+country that you have reason to believe are valid.

+

+ If, pursuant to or in connection with a single transaction or

+arrangement, you convey, or propagate by procuring conveyance of, a

+covered work, and grant a patent license to some of the parties

+receiving the covered work authorizing them to use, propagate, modify

+or convey a specific copy of the covered work, then the patent license

+you grant is automatically extended to all recipients of the covered

+work and works based on it.

+

+ A patent license is "discriminatory" if it does not include within

+the scope of its coverage, prohibits the exercise of, or is

+conditioned on the non-exercise of one or more of the rights that are

+specifically granted under this License. You may not convey a covered

+work if you are a party to an arrangement with a third party that is

+in the business of distributing software, under which you make payment

+to the third party based on the extent of your activity of conveying

+the work, and under which the third party grants, to any of the

+parties who would receive the covered work from you, a discriminatory

+patent license (a) in connection with copies of the covered work

+conveyed by you (or copies made from those copies), or (b) primarily

+for and in connection with specific products or compilations that

+contain the covered work, unless you entered into that arrangement,

+or that patent license was granted, prior to 28 March 2007.

+

+ Nothing in this License shall be construed as excluding or limiting

+any implied license or other defenses to infringement that may

+otherwise be available to you under applicable patent law.

+

+ 12. No Surrender of Others' Freedom.

+

+ If conditions are imposed on you (whether by court order, agreement or

+otherwise) that contradict the conditions of this License, they do not

+excuse you from the conditions of this License. If you cannot convey a

+covered work so as to satisfy simultaneously your obligations under this

+License and any other pertinent obligations, then as a consequence you may

+not convey it at all. For example, if you agree to terms that obligate you

+to collect a royalty for further conveying from those to whom you convey

+the Program, the only way you could satisfy both those terms and this

+License would be to refrain entirely from conveying the Program.

+

+ 13. Use with the GNU Affero General Public License.

+

+ Notwithstanding any other provision of this License, you have

+permission to link or combine any covered work with a work licensed

+under version 3 of the GNU Affero General Public License into a single

+combined work, and to convey the resulting work. The terms of this

+License will continue to apply to the part which is the covered work,

+but the special requirements of the GNU Affero General Public License,

+section 13, concerning interaction through a network will apply to the

+combination as such.

+

+ 14. Revised Versions of this License.

+

+ The Free Software Foundation may publish revised and/or new versions of

+the GNU General Public License from time to time. Such new versions will

+be similar in spirit to the present version, but may differ in detail to

+address new problems or concerns.

+

+ Each version is given a distinguishing version number. If the

+Program specifies that a certain numbered version of the GNU General

+Public License "or any later version" applies to it, you have the

+option of following the terms and conditions either of that numbered

+version or of any later version published by the Free Software

+Foundation. If the Program does not specify a version number of the

+GNU General Public License, you may choose any version ever published

+by the Free Software Foundation.

+

+ If the Program specifies that a proxy can decide which future

+versions of the GNU General Public License can be used, that proxy's

+public statement of acceptance of a version permanently authorizes you

+to choose that version for the Program.

+

+ Later license versions may give you additional or different

+permissions. However, no additional obligations are imposed on any

+author or copyright holder as a result of your choosing to follow a

+later version.

+

+ 15. Disclaimer of Warranty.

+

+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY

+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT

+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY

+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,

+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM

+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF

+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

+

+ 16. Limitation of Liability.

+

+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING

+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS

+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY

+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE

+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF

+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD

+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),

+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF

+SUCH DAMAGES.

+

+ 17. Interpretation of Sections 15 and 16.

+

+ If the disclaimer of warranty and limitation of liability provided

+above cannot be given local legal effect according to their terms,

+reviewing courts shall apply local law that most closely approximates

+an absolute waiver of all civil liability in connection with the

+Program, unless a warranty or assumption of liability accompanies a

+copy of the Program in return for a fee.

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "fmt"

+

+ "github.com/ava-labs/go-ethereum/core/types"

+ "github.com/ava-labs/go-ethereum/rlp"

+

+ "github.com/ava-labs/gecko/ids"

+ "github.com/ava-labs/gecko/snow/choices"

+ "github.com/ava-labs/gecko/snow/consensus/snowman"

+)

+

+// Block implements the snowman.Block interface

+type Block struct {

+ id ids.ID

+ ethBlock *types.Block

+ vm *VM

+}

+

+// ID implements the snowman.Block interface

+func (b *Block) ID() ids.ID { return b.id }

+

+// Accept implements the snowman.Block interface

+func (b *Block) Accept() {

+ b.vm.ctx.Log.Verbo("Block %s is accepted", b.ID())

+ b.vm.updateStatus(b.ID(), choices.Accepted)

+}

+

+// Reject implements the snowman.Block interface

+func (b *Block) Reject() {

+ b.vm.ctx.Log.Verbo("Block %s is rejected", b.ID())

+ b.vm.updateStatus(b.ID(), choices.Rejected)

+}

+

+// Status implements the snowman.Block interface

+func (b *Block) Status() choices.Status {

+ status := b.vm.getCachedStatus(b.ID())

+ if status == choices.Unknown && b.ethBlock != nil {

+ return choices.Processing

+ }

+ return status

+}

+

+// Parent implements the snowman.Block interface

+func (b *Block) Parent() snowman.Block {

+ parentID := ids.NewID(b.ethBlock.ParentHash())

+ block := &Block{

+ id: parentID,

+ ethBlock: b.vm.getCachedBlock(parentID),

+ vm: b.vm,

+ }

+ b.vm.ctx.Log.Verbo("Parent(%s) has status: %s", block.ID(), block.Status())

+ return block

+}

+

+// Verify implements the snowman.Block interface

+func (b *Block) Verify() error {

+ _, err := b.vm.chain.InsertChain([]*types.Block{b.ethBlock})

+ return err

+}

+

+// Bytes implements the snowman.Block interface

+func (b *Block) Bytes() []byte {

+ res, err := rlp.EncodeToBytes(b.ethBlock)

+ if err != nil {

+ panic(err)

+ }

+ return res

+}

+

+func (b *Block) String() string { return fmt.Sprintf("EVM block, ID = %s", b.ID()) }

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "errors"

+

+ "github.com/ava-labs/go-ethereum/ethdb"

+

+ "github.com/ava-labs/gecko/database"

+)

+

+var (

+ errOpNotSupported = errors.New("this operation is not supported")

+)

+

+// Database implements ethdb.Database

+type Database struct{ database.Database }

+

+// HasAncient returns an error as we don't have a backing chain freezer.

+func (db Database) HasAncient(kind string, number uint64) (bool, error) {

+ return false, errOpNotSupported

+}

+

+// Ancient returns an error as we don't have a backing chain freezer.

+func (db Database) Ancient(kind string, number uint64) ([]byte, error) { return nil, errOpNotSupported }

+

+// Ancients returns an error as we don't have a backing chain freezer.

+func (db Database) Ancients() (uint64, error) { return 0, errOpNotSupported }

+

+// AncientSize returns an error as we don't have a backing chain freezer.

+func (db Database) AncientSize(kind string) (uint64, error) { return 0, errOpNotSupported }

+

+// AppendAncient returns an error as we don't have a backing chain freezer.

+func (db Database) AppendAncient(number uint64, hash, header, body, receipts, td []byte) error {

+ return errOpNotSupported

+}

+

+// TruncateAncients returns an error as we don't have a backing chain freezer.

+func (db Database) TruncateAncients(items uint64) error { return errOpNotSupported }

+

+// Sync returns an error as we don't have a backing chain freezer.

+func (db Database) Sync() error { return errOpNotSupported }

+

+// NewBatch implements ethdb.Database

+func (db Database) NewBatch() ethdb.Batch { return Batch{db.Database.NewBatch()} }

+

+// NewIterator implements ethdb.Database

+func (db Database) NewIterator() ethdb.Iterator { return db.Database.NewIterator() }

+

+// NewIteratorWithPrefix implements ethdb.Database

+func (db Database) NewIteratorWithPrefix(prefix []byte) ethdb.Iterator {

+ return db.NewIteratorWithPrefix(prefix)

+}

+

+// NewIteratorWithStart implements ethdb.Database

+func (db Database) NewIteratorWithStart(start []byte) ethdb.Iterator {

+ return db.NewIteratorWithStart(start)

+}

+

+// Batch implements ethdb.Batch

+type Batch struct{ database.Batch }

+

+// Replay implements ethdb.Batch

+func (batch Batch) Replay(w ethdb.KeyValueWriter) error { return batch.Batch.Replay(w) }

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "github.com/ava-labs/gecko/ids"

+)

+

+// ID this VM should be referenced by

+var (

+ ID = ids.NewID([32]byte{'e', 'v', 'm'})

+)

+

+// Factory ...

+type Factory struct{}

+

+// New ...

+func (f *Factory) New() interface{} { return &VM{} }

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "context"

+ "crypto/rand"

+ "fmt"

+ "math/big"

+

+ "github.com/ava-labs/coreth"

+

+ "github.com/ava-labs/go-ethereum/common"

+ "github.com/ava-labs/go-ethereum/common/hexutil"

+ "github.com/ava-labs/go-ethereum/core/types"

+ "github.com/ava-labs/go-ethereum/crypto"

+)

+

+const (

+ version = "Athereum 1.0"

+)

+

+// test constants

+const (

+ GenesisTestAddr = "0x751a0b96e1042bee789452ecb20253fba40dbe85"

+ GenesisTestKey = "0xabd71b35d559563fea757f0f5edbde286fb8c043105b15abb7cd57189306d7d1"

+)

+

+// DebugAPI introduces helper functions for debuging

+type DebugAPI struct{ vm *VM }

+

+// SnowmanAPI introduces snowman specific functionality to the evm

+type SnowmanAPI struct{ vm *VM }

+

+// NetAPI offers network related API methods

+type NetAPI struct{ vm *VM }

+

+// NewNetAPI creates a new net API instance.

+func NewNetAPI(vm *VM) *NetAPI { return &NetAPI{vm} }

+

+// Listening returns an indication if the node is listening for network connections.

+func (s *NetAPI) Listening() bool { return true } // always listening

+

+// PeerCount returns the number of connected peers

+func (s *NetAPI) PeerCount() hexutil.Uint { return hexutil.Uint(0) } // TODO: report number of connected peers

+

+// Version returns the current ethereum protocol version.

+func (s *NetAPI) Version() string { return fmt.Sprintf("%d", s.vm.networkID) }

+

+// Web3API offers helper API methods

+type Web3API struct{}

+

+// ClientVersion returns the version of the vm running

+func (s *Web3API) ClientVersion() string { return version }

+

+// Sha3 returns the bytes returned by hashing [input] with Keccak256

+func (s *Web3API) Sha3(input hexutil.Bytes) hexutil.Bytes { return crypto.Keccak256(input) }

+

+// GetAcceptedFrontReply defines the reply that will be sent from the

+// GetAcceptedFront API call

+type GetAcceptedFrontReply struct {

+ Hash common.Hash `json:"hash"`

+ Number *big.Int `json:"number"`

+}

+

+// GetAcceptedFront returns the last accepted block's hash and height

+func (api *SnowmanAPI) GetAcceptedFront(ctx context.Context) (*GetAcceptedFrontReply, error) {

+ blk := api.vm.getLastAccepted().ethBlock

+ return &GetAcceptedFrontReply{

+ Hash: blk.Hash(),

+ Number: blk.Number(),

+ }, nil

+}

+

+// GetGenesisBalance returns the current funds in the genesis

+func (api *DebugAPI) GetGenesisBalance(ctx context.Context) (*hexutil.Big, error) {

+ lastAccepted := api.vm.getLastAccepted()

+ api.vm.ctx.Log.Verbo("Currently accepted block front: %s", lastAccepted.ethBlock.Hash().Hex())

+ state, err := api.vm.chain.BlockState(lastAccepted.ethBlock)

+ if err != nil {

+ return nil, err

+ }

+ return (*hexutil.Big)(state.GetBalance(common.HexToAddress(GenesisTestAddr))), nil

+}

+

+// SpendGenesis funds

+func (api *DebugAPI) SpendGenesis(ctx context.Context, nonce uint64) error {

+ api.vm.ctx.Log.Info("Spending the genesis")

+

+ value := big.NewInt(1000000000000)

+ gasLimit := 21000

+ gasPrice := big.NewInt(1000000000)

+

+ genPrivateKey, err := crypto.HexToECDSA(GenesisTestKey[2:])

+ if err != nil {

+ return err

+ }

+ bob, err := coreth.NewKey(rand.Reader)

+ if err != nil {

+ return err

+ }

+

+ tx := types.NewTransaction(nonce, bob.Address, value, uint64(gasLimit), gasPrice, nil)

+ signedTx, err := types.SignTx(tx, types.NewEIP155Signer(api.vm.chainID), genPrivateKey)

+ if err != nil {

+ return err

+ }

+

+ if err := api.vm.issueRemoteTxs([]*types.Transaction{signedTx}); err != nil {

+ return err

+ }

+

+ return nil

+}

+

+// IssueBlock to the chain

+func (api *DebugAPI) IssueBlock(ctx context.Context) error {

+ api.vm.ctx.Log.Info("Issuing a new block")

+

+ return api.vm.tryBlockGen()

+}

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "context"

+ "encoding/json"

+

+ "github.com/ava-labs/coreth/core"

+ "github.com/ava-labs/gecko/utils/formatting"

+)

+

+// StaticService defines the static API services exposed by the evm

+type StaticService struct{}

+

+// BuildGenesis returns the UTXOs such that at least one address in [args.Addresses] is

+// referenced in the UTXO.

+func (*StaticService) BuildGenesis(_ context.Context, args *core.Genesis) (formatting.CB58, error) {

+ bytes, err := json.Marshal(args)

+ return formatting.CB58{Bytes: bytes}, err

+}

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "math/big"

+ "testing"

+

+ "github.com/ava-labs/go-ethereum/common"

+ "github.com/ava-labs/go-ethereum/params"

+

+ "github.com/ava-labs/coreth/core"

+)

+

+func TestBuildGenesis(t *testing.T) {

+ expected := "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"

+

+ balance, success := new(big.Int).SetString("33b2e3c9fd0804000000000", 16)

+ if !success {

+ t.Fatal("Failed to initialize balance")

+ }

+

+ args := core.Genesis{

+ Config: &params.ChainConfig{

+ ChainID: big.NewInt(43110),

+ HomesteadBlock: big.NewInt(0),

+ DAOForkBlock: big.NewInt(0),

+ DAOForkSupport: true,

+ EIP150Block: big.NewInt(0),

+ EIP150Hash: common.HexToHash("0x2086799aeebeae135c246c65021c82b4e15a2c451340993aacfd2751886514f0"),

+ EIP155Block: big.NewInt(0),

+ EIP158Block: big.NewInt(0),

+ ByzantiumBlock: big.NewInt(0),

+ ConstantinopleBlock: big.NewInt(0),

+ PetersburgBlock: big.NewInt(0),

+ },

+ Nonce: 0,

+ Timestamp: 0,

+ ExtraData: []byte{},

+ GasLimit: 100000000,

+ Difficulty: big.NewInt(0),

+ Mixhash: common.HexToHash("0x0000000000000000000000000000000000000000000000000000000000000000"),

+ Coinbase: common.HexToAddress("0x0000000000000000000000000000000000000000"),

+ Alloc: core.GenesisAlloc{

+ common.HexToAddress("751a0b96e1042bee789452ecb20253fba40dbe85"): core.GenesisAccount{

+ Balance: balance,

+ },

+ },

+ Number: 0,

+ GasUsed: 0,

+ ParentHash: common.HexToHash("0x0000000000000000000000000000000000000000000000000000000000000000"),

+ }

+

+ ss := StaticService{}

+ result, err := ss.BuildGenesis(nil, &args)

+ if err != nil {

+ t.Fatal(err)

+ }

+

+ if result.String() != expected {

+ t.Fatalf("StaticService.BuildGenesis:\nReturned: %s\nExpected: %s", result, expected)

+ }

+}

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "crypto/rand"

+ "encoding/json"

+ "errors"

+ "fmt"

+ "math/big"

+ "sync"

+ "sync/atomic"

+ "time"

+

+ "github.com/ava-labs/coreth"

+ "github.com/ava-labs/coreth/core"

+ "github.com/ava-labs/coreth/eth"

+ "github.com/ava-labs/coreth/node"

+

+ "github.com/ava-labs/go-ethereum/common"

+ "github.com/ava-labs/go-ethereum/core/types"

+ "github.com/ava-labs/go-ethereum/rlp"

+ "github.com/ava-labs/go-ethereum/rpc"

+

+ "github.com/ava-labs/gecko/cache"

+ "github.com/ava-labs/gecko/database"

+ "github.com/ava-labs/gecko/ids"

+ "github.com/ava-labs/gecko/snow"

+ "github.com/ava-labs/gecko/snow/choices"

+ "github.com/ava-labs/gecko/snow/consensus/snowman"

+ "github.com/ava-labs/gecko/utils/timer"

+

+ commonEng "github.com/ava-labs/gecko/snow/engine/common"

+)

+

+const (

+ lastAcceptedKey = "snowman_lastAccepted"

+)

+

+const (

+ minBlockTime = 250 * time.Millisecond

+ maxBlockTime = 1000 * time.Millisecond

+ batchSize = 250

+)

+

+const (

+ bdTimerStateMin = iota

+ bdTimerStateMax

+ bdTimerStateLong

+)

+

+var (

+ errEmptyBlock = errors.New("empty block")

+ errCreateBlock = errors.New("couldn't create block")

+ errUnknownBlock = errors.New("unknown block")

+ errBlockFrequency = errors.New("too frequent block issuance")

+ errUnsupportedFXs = errors.New("unsupported feature extensions")

+)

+

+func maxDuration(x, y time.Duration) time.Duration {

+ if x > y {

+ return x

+ }

+ return y

+}

+

+// VM implements the snowman.ChainVM interface

+type VM struct {

+ ctx *snow.Context

+

+ chainID *big.Int

+ networkID uint64

+ chain *coreth.ETHChain

+ chaindb Database

+ newBlockChan chan *Block

+ networkChan chan<- commonEng.Message

+ newTxPoolHeadChan chan core.NewTxPoolHeadEvent

+

+ txPoolStabilizedHead common.Hash

+ txPoolStabilizedOk chan struct{}

+ txPoolStabilizedLock sync.Mutex

+

+ metalock sync.Mutex

+ blockCache, blockStatusCache cache.LRU

+ lastAccepted *Block

+ writingMetadata uint32

+

+ bdlock sync.Mutex

+ blockDelayTimer *timer.Timer

+ bdTimerState int8

+ bdGenWaitFlag bool

+ bdGenFlag bool

+

+ genlock sync.Mutex

+ txSubmitChan <-chan struct{}

+}

+

+/*

+ ******************************************************************************

+ ********************************* Snowman API ********************************

+ ******************************************************************************

+ */

+

+// Initialize implements the snowman.ChainVM interface

+func (vm *VM) Initialize(

+ ctx *snow.Context,

+ db database.Database,

+ b []byte,

+ toEngine chan<- commonEng.Message,

+ fxs []*commonEng.Fx,

+) error {

+ if len(fxs) > 0 {

+ return errUnsupportedFXs

+ }

+

+ vm.ctx = ctx

+ vm.chaindb = Database{db}

+ g := new(core.Genesis)

+ err := json.Unmarshal(b, g)

+ if err != nil {

+ return err

+ }

+

+ vm.chainID = g.Config.ChainID

+

+ config := eth.DefaultConfig

+ config.ManualCanonical = true

+ config.Genesis = g

+ config.Miner.ManualMining = true

+ config.Miner.DisableUncle = true

+ if err := config.SetGCMode("archive"); err != nil {

+ panic(err)

+ }

+ nodecfg := node.Config{NoUSB: true}

+ chain := coreth.NewETHChain(&config, &nodecfg, nil, vm.chaindb)

+ vm.chain = chain

+ vm.networkID = config.NetworkId

+ chain.SetOnHeaderNew(func(header *types.Header) {

+ hid := make([]byte, 32)

+ _, err := rand.Read(hid)

+ if err != nil {

+ panic("cannot generate hid")

+ }

+ header.Extra = append(header.Extra, hid...)

+ })

+ chain.SetOnSeal(func(block *types.Block) error {

+ if len(block.Transactions()) == 0 {

+ // this could happen due to the async logic of geth tx pool

+ vm.newBlockChan <- nil

+ return errEmptyBlock

+ }

+ return nil

+ })

+ chain.SetOnSealFinish(func(block *types.Block) error {

+ vm.ctx.Log.Verbo("EVM sealed a block")

+

+ blk := &Block{

+ id: ids.NewID(block.Hash()),

+ ethBlock: block,

+ vm: vm,

+ }

+ vm.newBlockChan <- blk

+ vm.updateStatus(ids.NewID(block.Hash()), choices.Processing)

+ vm.txPoolStabilizedLock.Lock()

+ vm.txPoolStabilizedHead = block.Hash()

+ vm.txPoolStabilizedLock.Unlock()

+ return nil

+ })

+ chain.SetOnQueryAcceptedBlock(func() *types.Block {

+ return vm.getLastAccepted().ethBlock

+ })

+ vm.blockCache = cache.LRU{Size: 2048}

+ vm.blockStatusCache = cache.LRU{Size: 1024}

+ vm.newBlockChan = make(chan *Block)

+ vm.networkChan = toEngine

+ vm.blockDelayTimer = timer.NewTimer(func() {

+ vm.bdlock.Lock()

+ switch vm.bdTimerState {

+ case bdTimerStateMin:

+ vm.bdTimerState = bdTimerStateMax

+ vm.blockDelayTimer.SetTimeoutIn(maxDuration(maxBlockTime-minBlockTime, 0))

+ case bdTimerStateMax:

+ vm.bdTimerState = bdTimerStateLong

+ }

+ tryAgain := vm.bdGenWaitFlag

+ vm.bdlock.Unlock()

+ if tryAgain {

+ vm.tryBlockGen()

+ }

+ })

+ go ctx.Log.RecoverAndPanic(vm.blockDelayTimer.Dispatch)

+

+ vm.bdTimerState = bdTimerStateLong

+ vm.bdGenWaitFlag = true

+ vm.newTxPoolHeadChan = make(chan core.NewTxPoolHeadEvent, 1)

+ vm.txPoolStabilizedOk = make(chan struct{}, 1)

+ chain.GetTxPool().SubscribeNewHeadEvent(vm.newTxPoolHeadChan)

+ // TODO: shutdown this go routine

+ go ctx.Log.RecoverAndPanic(func() {

+ for {

+ select {

+ case h := <-vm.newTxPoolHeadChan:

+ vm.txPoolStabilizedLock.Lock()

+ if vm.txPoolStabilizedHead == h.Block.Hash() {

+ vm.txPoolStabilizedOk <- struct{}{}

+ vm.txPoolStabilizedHead = common.Hash{}

+ }

+ vm.txPoolStabilizedLock.Unlock()

+ }

+ }

+ })

+ chain.Start()

+

+ var lastAccepted *types.Block

+ if b, err := vm.chaindb.Get([]byte(lastAcceptedKey)); err == nil {

+ var hash common.Hash

+ if err = rlp.DecodeBytes(b, &hash); err == nil {

+ if block := chain.GetBlockByHash(hash); block == nil {

+ vm.ctx.Log.Debug("lastAccepted block not found in chaindb")

+ } else {

+ lastAccepted = block

+ }

+ }

+ }

+ if lastAccepted == nil {

+ vm.ctx.Log.Debug("lastAccepted is unavailable, setting to the genesis block")

+ lastAccepted = chain.GetGenesisBlock()

+ }

+ vm.lastAccepted = &Block{

+ id: ids.NewID(lastAccepted.Hash()),

+ ethBlock: lastAccepted,

+ vm: vm,

+ }

+ vm.ctx.Log.Info(fmt.Sprintf("lastAccepted = %s", vm.lastAccepted.ethBlock.Hash().Hex()))

+

+ // TODO: shutdown this go routine

+ go vm.ctx.Log.RecoverAndPanic(func() {

+ vm.txSubmitChan = vm.chain.GetTxSubmitCh()

+ for {

+ select {

+ case <-vm.txSubmitChan:

+ vm.ctx.Log.Verbo("New tx detected, trying to generate a block")

+ vm.tryBlockGen()

+ case <-time.After(5 * time.Second):

+ vm.tryBlockGen()

+ }

+ }

+ })

+

+ return nil

+}

+

+// Shutdown implements the snowman.ChainVM interface

+func (vm *VM) Shutdown() {

+ if vm.ctx == nil {

+ return

+ }

+

+ vm.writeBackMetadata()

+ vm.chain.Stop()

+}

+

+// BuildBlock implements the snowman.ChainVM interface

+func (vm *VM) BuildBlock() (snowman.Block, error) {

+ vm.chain.GenBlock()

+ block := <-vm.newBlockChan

+ if block == nil {

+ return nil, errCreateBlock

+ }

+ // reset the min block time timer

+ vm.bdlock.Lock()

+ vm.bdTimerState = bdTimerStateMin

+ vm.bdGenWaitFlag = false

+ vm.bdGenFlag = false

+ vm.blockDelayTimer.SetTimeoutIn(minBlockTime)

+ vm.bdlock.Unlock()

+

+ vm.ctx.Log.Debug("built block 0x%x", block.ID().Bytes())

+ // make sure Tx Pool is updated

+ <-vm.txPoolStabilizedOk

+ return block, nil

+}

+

+// ParseBlock implements the snowman.ChainVM interface

+func (vm *VM) ParseBlock(b []byte) (snowman.Block, error) {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+

+ ethBlock := new(types.Block)

+ if err := rlp.DecodeBytes(b, ethBlock); err != nil {

+ return nil, err

+ }

+ block := &Block{

+ id: ids.NewID(ethBlock.Hash()),

+ ethBlock: ethBlock,

+ vm: vm,

+ }

+ vm.blockCache.Put(block.ID(), block)

+ return block, nil

+}

+

+// GetBlock implements the snowman.ChainVM interface

+func (vm *VM) GetBlock(id ids.ID) (snowman.Block, error) {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+

+ block := vm.getBlock(id)

+ if block == nil {

+ return nil, errUnknownBlock

+ }

+ return block, nil

+}

+

+// SetPreference sets what the current tail of the chain is

+func (vm *VM) SetPreference(blkID ids.ID) {

+ err := vm.chain.SetTail(blkID.Key())

+ vm.ctx.Log.AssertNoError(err)

+}

+

+// LastAccepted returns the ID of the block that was last accepted

+func (vm *VM) LastAccepted() ids.ID {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+

+ return vm.lastAccepted.ID()

+}

+

+// CreateHandlers makes new http handlers that can handle API calls

+func (vm *VM) CreateHandlers() map[string]*commonEng.HTTPHandler {

+ handler := vm.chain.NewRPCHandler()

+ vm.chain.AttachEthService(handler, []string{"eth", "personal", "txpool"})

+ handler.RegisterName("net", &NetAPI{vm})

+ handler.RegisterName("snowman", &SnowmanAPI{vm})

+ handler.RegisterName("web3", &Web3API{})

+ handler.RegisterName("debug", &DebugAPI{vm})

+

+ return map[string]*commonEng.HTTPHandler{

+ "/rpc": &commonEng.HTTPHandler{LockOptions: commonEng.NoLock, Handler: handler},

+ "/ws": &commonEng.HTTPHandler{LockOptions: commonEng.NoLock, Handler: handler.WebsocketHandler([]string{"*"})},

+ }

+}

+

+// CreateStaticHandlers makes new http handlers that can handle API calls

+func (vm *VM) CreateStaticHandlers() map[string]*commonEng.HTTPHandler {

+ handler := rpc.NewServer()

+ handler.RegisterName("static", &StaticService{})

+ return map[string]*commonEng.HTTPHandler{

+ "/rpc": &commonEng.HTTPHandler{LockOptions: commonEng.NoLock, Handler: handler},

+ "/ws": &commonEng.HTTPHandler{LockOptions: commonEng.NoLock, Handler: handler.WebsocketHandler([]string{"*"})},

+ }

+}

+

+/*

+ ******************************************************************************

+ *********************************** Helpers **********************************

+ ******************************************************************************

+ */

+

+func (vm *VM) updateStatus(blockID ids.ID, status choices.Status) {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+

+ if status == choices.Accepted {

+ vm.lastAccepted = vm.getBlock(blockID)

+ // TODO: improve this naive implementation

+ if atomic.SwapUint32(&vm.writingMetadata, 1) == 0 {

+ go vm.ctx.Log.RecoverAndPanic(vm.writeBackMetadata)

+ }

+ }

+ vm.blockStatusCache.Put(blockID, status)

+}

+

+func (vm *VM) getCachedBlock(blockID ids.ID) *types.Block {

+ return vm.chain.GetBlockByHash(blockID.Key())

+}

+

+func (vm *VM) tryBlockGen() error {

+ vm.bdlock.Lock()

+ defer vm.bdlock.Unlock()

+ if vm.bdGenFlag {

+ // skip if one call already generates a block in this round

+ return nil

+ }

+ vm.bdGenWaitFlag = true

+

+ vm.genlock.Lock()

+ defer vm.genlock.Unlock()

+ // get pending size

+ size, err := vm.chain.PendingSize()

+ if err != nil {

+ return err

+ }

+ if size == 0 {

+ return nil

+ }

+

+ switch vm.bdTimerState {

+ case bdTimerStateMin:

+ return nil

+ case bdTimerStateMax:

+ if size < batchSize {

+ return nil

+ }

+ case bdTimerStateLong:

+ // timeout; go ahead and generate a new block anyway

+ }

+ select {

+ case vm.networkChan <- commonEng.PendingTxs:

+ // successfully push out the notification; this round ends

+ vm.bdGenFlag = true

+ default:

+ return errBlockFrequency

+ }

+ return nil

+}

+

+func (vm *VM) getCachedStatus(blockID ids.ID) choices.Status {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+ status := choices.Processing

+

+ if statusIntf, ok := vm.blockStatusCache.Get(blockID); ok {

+ status = statusIntf.(choices.Status)

+ } else {

+ blk := vm.chain.GetBlockByHash(blockID.Key())

+ if blk == nil {

+ return choices.Unknown

+ }

+ acceptedBlk := vm.lastAccepted.ethBlock

+

+ // TODO: There must be a better way of doing this.

+ // Traverse up the chain from the lower block until the indices match

+ highBlock := blk

+ lowBlock := acceptedBlk

+ if highBlock.Number().Cmp(lowBlock.Number()) < 0 {

+ highBlock, lowBlock = lowBlock, highBlock

+ }

+ for highBlock.Number().Cmp(lowBlock.Number()) > 0 {

+ highBlock = vm.chain.GetBlockByHash(highBlock.ParentHash())

+ }

+

+ if highBlock.Hash() == lowBlock.Hash() { // on the same branch

+ if blk.Number().Cmp(acceptedBlk.Number()) <= 0 {

+ status = choices.Accepted

+ }

+ } else { // on different branches

+ status = choices.Rejected

+ }

+ }

+

+ vm.blockStatusCache.Put(blockID, status)

+ return status

+}

+

+func (vm *VM) getBlock(id ids.ID) *Block {

+ if blockIntf, ok := vm.blockCache.Get(id); ok {

+ return blockIntf.(*Block)

+ }

+ ethBlock := vm.getCachedBlock(id)

+ if ethBlock == nil {

+ return nil

+ }

+ block := &Block{

+ id: ids.NewID(ethBlock.Hash()),

+ ethBlock: ethBlock,

+ vm: vm,

+ }

+ vm.blockCache.Put(id, block)

+ return block

+}

+

+func (vm *VM) issueRemoteTxs(txs []*types.Transaction) error {

+ errs := vm.chain.AddRemoteTxs(txs)

+ for _, err := range errs {

+ if err != nil {

+ return err

+ }

+ }

+ return vm.tryBlockGen()

+}

+

+func (vm *VM) writeBackMetadata() {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+

+ b, err := rlp.EncodeToBytes(vm.lastAccepted.ethBlock.Hash())

+ if err != nil {

+ vm.ctx.Log.Error("snowman-eth: error while writing back metadata")

+ return

+ }

+ vm.ctx.Log.Debug("writing back metadata")

+ vm.chaindb.Put([]byte(lastAcceptedKey), b)

+ atomic.StoreUint32(&vm.writingMetadata, 0)

+}

+

+func (vm *VM) getLastAccepted() *Block {

+ vm.metalock.Lock()

+ defer vm.metalock.Unlock()

+

+ return vm.lastAccepted

+}

+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.

+// See the file LICENSE for licensing terms.

+

+package evm

+

+import (

+ "encoding/json"

+ "testing"

+

+ "github.com/ava-labs/coreth/core"

+)

+

+func TestParseGenesis(t *testing.T) {

+ genesis := []byte(`{"config":{"chainId":43110,"homesteadBlock":0,"daoForkBlock":0,"daoForkSupport":true,"eip150Block":0,"eip150Hash":"0x2086799aeebeae135c246c65021c82b4e15a2c451340993aacfd2751886514f0","eip155Block":0,"eip158Block":0,"byzantiumBlock":0,"constantinopleBlock":0,"petersburgBlock":0},"nonce":"0x0","timestamp":"0x0","extraData":"0x00","gasLimit":"0x5f5e100","difficulty":"0x0","mixHash":"0x0000000000000000000000000000000000000000000000000000000000000000","coinbase":"0x0000000000000000000000000000000000000000","alloc":{"751a0b96e1042bee789452ecb20253fba40dbe85":{"balance":"0x33b2e3c9fd0804000000000"}},"number":"0x0","gasUsed":"0x0","parentHash":"0x0000000000000000000000000000000000000000000000000000000000000000"}`)

+

+ genesisBlock := new(core.Genesis)

+ err := json.Unmarshal(genesis, genesisBlock)

+ if err != nil {

+ t.Fatal(err)

+ }

+

+ marshalledBytes, err := json.Marshal(genesisBlock)

+ if err != nil {

+ t.Fatal(err)

+ }

+

+ secondGenesisBlock := new(core.Genesis)

+ err = json.Unmarshal(marshalledBytes, secondGenesisBlock)

+ if err != nil {

+ t.Fatal(err)

+ }

+}

+package main

+

+import (

+ "github.com/hashicorp/go-plugin"

+

+ "github.com/ava-labs/gecko/vms/rpcchainvm"

+

+ "github.com/ava-labs/coreth/plugin/evm"

+)

+

+func main() {

+ plugin.Serve(&plugin.ServeConfig{

+ HandshakeConfig: rpcchainvm.Handshake,

+ Plugins: map[string]plugin.Plugin{

+ "vm": rpcchainvm.New(&evm.VM{}),

+ },

+

+ // A non-nil value here enables gRPC serving for this plugin...

+ GRPCServer: plugin.DefaultGRPCServer,

+ })

+}