1 files changed, 301 insertions, 0 deletions
diff --git a/accounts/keystore/account_cache.go b/accounts/keystore/account_cache.go
new file mode 100644
index 0000000..2067ccb
--- /dev/null
+++ b/accounts/keystore/account_cache.go
@@ -0,0 +1,301 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package keystore
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/ava-labs/coreth/accounts"
+	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ava-labs/go-ethereum/log"
+	mapset "github.com/deckarep/golang-set"
+)
+
+// Minimum amount of time between cache reloads. This limit applies if the platform does
+// not support change notifications. It also applies if the keystore directory does not
+// exist yet, the code will attempt to create a watcher at most this often.
+const minReloadInterval = 2 * time.Second
+
+type accountsByURL []accounts.Account
+
+func (s accountsByURL) Len() int           { return len(s) }
+func (s accountsByURL) Less(i, j int) bool { return s[i].URL.Cmp(s[j].URL) < 0 }
+func (s accountsByURL) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
+// AmbiguousAddrError is returned when attempting to unlock
+// an address for which more than one file exists.
+type AmbiguousAddrError struct {
+	Addr    common.Address
+	Matches []accounts.Account
+}
+
+func (err *AmbiguousAddrError) Error() string {
+	files := ""
+	for i, a := range err.Matches {
+		files += a.URL.Path
+		if i < len(err.Matches)-1 {
+			files += ", "
+		}
+	}
+	return fmt.Sprintf("multiple keys match address (%s)", files)
+}
+
+// accountCache is a live index of all accounts in the keystore.
+type accountCache struct {
+	keydir   string
+	watcher  *watcher
+	mu       sync.Mutex
+	all      accountsByURL
+	byAddr   map[common.Address][]accounts.Account
+	throttle *time.Timer
+	notify   chan struct{}
+	fileC    fileCache
+}
+
+func newAccountCache(keydir string) (*accountCache, chan struct{}) {
+	ac := &accountCache{
+		keydir: keydir,
+		byAddr: make(map[common.Address][]accounts.Account),
+		notify: make(chan struct{}, 1),
+		fileC:  fileCache{all: mapset.NewThreadUnsafeSet()},
+	}
+	ac.watcher = newWatcher(ac)
+	return ac, ac.notify
+}
+
+func (ac *accountCache) accounts() []accounts.Account {
+	ac.maybeReload()
+	ac.mu.Lock()
+	defer ac.mu.Unlock()
+	cpy := make([]accounts.Account, len(ac.all))
+	copy(cpy, ac.all)
+	return cpy
+}
+
+func (ac *accountCache) hasAddress(addr common.Address) bool {
+	ac.maybeReload()
+	ac.mu.Lock()
+	defer ac.mu.Unlock()
+	return len(ac.byAddr[addr]) > 0
+}
+
+func (ac *accountCache) add(newAccount accounts.Account) {
+	ac.mu.Lock()
+	defer ac.mu.Unlock()
+
+	i := sort.Search(len(ac.all), func(i int) bool { return ac.all[i].URL.Cmp(newAccount.URL) >= 0 })
+	if i < len(ac.all) && ac.all[i] == newAccount {
+		return
+	}
+	// newAccount is not in the cache.
+	ac.all = append(ac.all, accounts.Account{})
+	copy(ac.all[i+1:], ac.all[i:])
+	ac.all[i] = newAccount
+	ac.byAddr[newAccount.Address] = append(ac.byAddr[newAccount.Address], newAccount)
+}
+
+// note: removed needs to be unique here (i.e. both File and Address must be set).
+func (ac *accountCache) delete(removed accounts.Account) {
+	ac.mu.Lock()
+	defer ac.mu.Unlock()
+
+	ac.all = removeAccount(ac.all, removed)
+	if ba := removeAccount(ac.byAddr[removed.Address], removed); len(ba) == 0 {
+		delete(ac.byAddr, removed.Address)
+	} else {
+		ac.byAddr[removed.Address] = ba
+	}
+}
+
+// deleteByFile removes an account referenced by the given path.
+func (ac *accountCache) deleteByFile(path string) {
+	ac.mu.Lock()
+	defer ac.mu.Unlock()
+	i := sort.Search(len(ac.all), func(i int) bool { return ac.all[i].URL.Path >= path })
+
+	if i < len(ac.all) && ac.all[i].URL.Path == path {
+		removed := ac.all[i]
+		ac.all = append(ac.all[:i], ac.all[i+1:]...)
+		if ba := removeAccount(ac.byAddr[removed.Address], removed); len(ba) == 0 {
+			delete(ac.byAddr, removed.Address)
+		} else {
+			ac.byAddr[removed.Address] = ba
+		}
+	}
+}
+
+func removeAccount(slice []accounts.Account, elem accounts.Account) []accounts.Account {
+	for i := range slice {
+		if slice[i] == elem {
+			return append(slice[:i], slice[i+1:]...)
+		}
+	}
+	return slice
+}
+
+// find returns the cached account for address if there is a unique match.
+// The exact matching rules are explained by the documentation of accounts.Account.
+// Callers must hold ac.mu.
+func (ac *accountCache) find(a accounts.Account) (accounts.Account, error) {
+	// Limit search to address candidates if possible.
+	matches := ac.all
+	if (a.Address != common.Address{}) {
+		matches = ac.byAddr[a.Address]
+	}
+	if a.URL.Path != "" {
+		// If only the basename is specified, complete the path.
+		if !strings.ContainsRune(a.URL.Path, filepath.Separator) {
+			a.URL.Path = filepath.Join(ac.keydir, a.URL.Path)
+		}
+		for i := range matches {
+			if matches[i].URL == a.URL {
+				return matches[i], nil
+			}
+		}
+		if (a.Address == common.Address{}) {
+			return accounts.Account{}, ErrNoMatch
+		}
+	}
+	switch len(matches) {
+	case 1:
+		return matches[0], nil
+	case 0:
+		return accounts.Account{}, ErrNoMatch
+	default:
+		err := &AmbiguousAddrError{Addr: a.Address, Matches: make([]accounts.Account, len(matches))}
+		copy(err.Matches, matches)
+		sort.Sort(accountsByURL(err.Matches))
+		return accounts.Account{}, err
+	}
+}
+
+func (ac *accountCache) maybeReload() {
+	ac.mu.Lock()
+
+	if ac.watcher.running {
+		ac.mu.Unlock()
+		return // A watcher is running and will keep the cache up-to-date.
+	}
+	if ac.throttle == nil {
+		ac.throttle = time.NewTimer(0)
+	} else {
+		select {
+		case <-ac.throttle.C:
+		default:
+			ac.mu.Unlock()
+			return // The cache was reloaded recently.
+		}
+	}
+	// No watcher running, start it.
+	ac.watcher.start()
+	ac.throttle.Reset(minReloadInterval)
+	ac.mu.Unlock()
+	ac.scanAccounts()
+}
+
+func (ac *accountCache) close() {
+	ac.mu.Lock()
+	ac.watcher.close()
+	if ac.throttle != nil {
+		ac.throttle.Stop()
+	}
+	if ac.notify != nil {
+		close(ac.notify)
+		ac.notify = nil
+	}
+	ac.mu.Unlock()
+}
+
+// scanAccounts checks if any changes have occurred on the filesystem, and
+// updates the account cache accordingly
+func (ac *accountCache) scanAccounts() error {
+	// Scan the entire folder metadata for file changes
+	creates, deletes, updates, err := ac.fileC.scan(ac.keydir)
+	if err != nil {
+		log.Debug("Failed to reload keystore contents", "err", err)
+		return err
+	}
+	if creates.Cardinality() == 0 && deletes.Cardinality() == 0 && updates.Cardinality() == 0 {
+		return nil
+	}
+	// Create a helper method to scan the contents of the key files
+	var (
+		buf = new(bufio.Reader)
+		key struct {
+			Address string `json:"address"`
+		}
+	)
+	readAccount := func(path string) *accounts.Account {
+		fd, err := os.Open(path)
+		if err != nil {
+			log.Trace("Failed to open keystore file", "path", path, "err", err)
+			return nil
+		}
+		defer fd.Close()
+		buf.Reset(fd)
+		// Parse the address.
+		key.Address = ""
+		err = json.NewDecoder(buf).Decode(&key)
+		addr := common.HexToAddress(key.Address)
+		switch {
+		case err != nil:
+			log.Debug("Failed to decode keystore key", "path", path, "err", err)
+		case (addr == common.Address{}):
+			log.Debug("Failed to decode keystore key", "path", path, "err", "missing or zero address")
+		default:
+			return &accounts.Account{
+				Address: addr,
+				URL:     accounts.URL{Scheme: KeyStoreScheme, Path: path},
+			}
+		}
+		return nil
+	}
+	// Process all the file diffs
+	start := time.Now()
+
+	for _, p := range creates.ToSlice() {
+		if a := readAccount(p.(string)); a != nil {
+			ac.add(*a)
+		}
+	}
+	for _, p := range deletes.ToSlice() {
+		ac.deleteByFile(p.(string))
+	}
+	for _, p := range updates.ToSlice() {
+		path := p.(string)
+		ac.deleteByFile(path)
+		if a := readAccount(path); a != nil {
+			ac.add(*a)
+		}
+	}
+	end := time.Now()
+
+	select {
+	case ac.notify <- struct{}{}:
+	default:
+	}
+	log.Trace("Handled keystore changes", "time", end.Sub(start))
+	return nil
+}