WIP: random failure test (with emulated storage)

1 files changed, 117 insertions, 0 deletions

diff --git a/tests/common/mod.rs b/tests/common/mod.rs
new file mode 100644
index 0000000..fd98539
--- /dev/null
+++ b/tests/common/mod.rs
@@ -0,0 +1,117 @@
+#[cfg(test)]
+#[allow(dead_code)]
+
+extern crate growthring;
+use growthring::wal::{WALFile, WALStore, WALPos, WALBytes};
+use std::collections::{HashMap, hash_map::Entry};
+use std::cell::RefCell;
+use std::rc::Rc;
+
+/*
+thread_local! {
+    //pub static RNG: RefCell<rand::rngs::StdRng> = RefCell::new(<rand::rngs::StdRng as rand::SeedableRng>::from_seed([0; 32]));
+    pub static RNG: RefCell<rand::rngs::ThreadRng> = RefCell::new(rand::thread_rng());
+}
+
+pub fn gen_rand_letters(i: usize) -> String {
+    //let mut rng = rand::thread_rng();
+    RNG.with(|rng| {
+        (0..i).map(|_| (rng.borrow_mut().gen::<u8>() % 26 + 'a' as u8) as char).collect()
+    })
+}
+*/
+
+struct FileContentEmul(RefCell<Vec<u8>>);
+
+impl FileContentEmul {
+    pub fn new() -> Self { FileContentEmul(RefCell::new(Vec::new())) }
+}
+
+impl std::ops::Deref for FileContentEmul {
+    type Target = RefCell<Vec<u8>>;
+    fn deref(&self) -> &Self::Target {&self.0}
+}
+
+/// Emulate the a virtual file handle.
+pub struct WALFileEmul {
+    file: Rc<FileContentEmul>
+}
+
+impl WALFile for WALFileEmul {
+    fn allocate(&self, offset: WALPos, length: usize) -> Result<(), ()> {
+        let offset = offset as usize;
+        if offset + length > self.file.borrow().len() {
+            self.file.borrow_mut().resize(offset + length, 0)
+        }
+        for v in &mut self.file.borrow_mut()[offset..offset + length] { *v = 0 }
+        Ok(())
+    }
+
+    fn truncate(&self, length: usize) -> Result<(), ()> {
+        self.file.borrow_mut().resize(length, 0);
+        Ok(())
+    }
+
+    fn write(&self, offset: WALPos, data: WALBytes) {
+        let offset = offset as usize;
+        &self.file.borrow_mut()[offset..offset + data.len()].copy_from_slice(&data);
+    }
+
+    fn read(&self, offset: WALPos, length: usize) -> Option<WALBytes> {
+        let offset = offset as usize;
+        let file = self.file.borrow();
+        if offset + length > file.len() { None }
+        else {
+            Some((&file[offset..offset + length]).to_vec().into_boxed_slice())
+        }
+    }
+}
+
+pub struct WALStoreEmulState{
+    files: HashMap<String, Rc<FileContentEmul>>,
+}
+
+impl WALStoreEmulState {
+    pub fn new() -> Self { WALStoreEmulState { files: HashMap::new() } }
+}
+
+/// Emulate the persistent storage state.
+pub struct WALStoreEmul<'a>(&'a mut WALStoreEmulState);
+
+impl<'a> WALStoreEmul<'a> {
+    pub fn new(state: &'a mut WALStoreEmulState) -> Self {
+        WALStoreEmul(state)
+    }
+}
+
+impl<'a> WALStore for WALStoreEmul<'a> {
+    type FileNameIter = std::vec::IntoIter<String>;
+
+    fn open_file(&mut self, filename: &str, touch: bool) -> Option<Box<dyn WALFile>> {
+        match self.0.files.entry(filename.to_string()) {
+            Entry::Occupied(e) => Some(Box::new(WALFileEmul { file: e.get().clone() })),
+            Entry::Vacant(e) => if touch {
+                Some(Box::new(
+                    WALFileEmul { file: e.insert(Rc::new(FileContentEmul::new())).clone() }))
+            } else {
+                None
+            }
+        }
+    }
+
+    fn remove_file(&mut self, filename: &str) -> Result<(), ()> {
+        self.0.files.remove(filename).ok_or(()).and_then(|_| Ok(()))
+    }
+
+    fn enumerate_files(&self) -> Self::FileNameIter {
+        let mut logfiles = Vec::new();
+        for (fname, _) in self.0.files.iter() {
+            logfiles.push(fname.clone())
+        }
+        logfiles.into_iter()
+    }
+
+    fn apply_payload(&mut self, payload: WALBytes) {
+        println!("apply_payload(payload={})", std::str::from_utf8(&payload).unwrap())
+    }
+}