Merge pull request #343 from matthiasbeyer/libimagstorestdhook/flock

Libimagstorestdhook/flock

libimagstorestdhook/Cargo.toml

@@ -6,6 +6,7 @@ authors = ["Matthias Beyer <mail@beyermatthias.de>"]
 [dependencies]
 toml = "0.1.25"
 log = "0.3.5"
+fs2 = "0.2.3"
 
 [dependencies.libimagstore]
 path = "../libimagstore"

libimagstorestdhook/src/flock.rs

@@ -0,0 +1,127 @@
+use std::io::Result as IoResult;
+use std::path::PathBuf;
+
+use toml::Value;
+
+use fs2::FileExt;
+
+use libimagstore::hook::Hook;
+use libimagstore::hook::accessor::HookDataAccessor as HDA;
+use libimagstore::hook::accessor::HookDataAccessorProvider;
+use libimagstore::hook::accessor::StoreIdAccessor;
+use libimagstore::hook::accessor::MutableHookDataAccessor;
+use libimagstore::hook::accessor::NonMutableHookDataAccessor;
+use libimagstore::hook::result::HookResult;
+use libimagstore::hook::error::{HookError, HookErrorKind};
+use libimagstore::storeid::StoreId;
+use libimagstore::store::FileLockEntry;
+use libimagstore::store::Entry;
+
+trait EntryFlock {
+    fn lock(&self, store_location: &PathBuf) -> IoResult<()>;
+    fn unlock(&self, store_location: &PathBuf) -> IoResult<()>;
+}
+
+impl EntryFlock for Entry {
+
+    fn lock(&self, store_location: &PathBuf) -> IoResult<()> {
+        use std::fs::File;
+
+        let mut location = store_location.clone();
+        location.push(self.get_location());
+
+        File::open(location).and_then(|file| file.lock_exclusive())
+    }
+
+    fn unlock(&self, store_location: &PathBuf) -> IoResult<()> {
+        use std::fs::File;
+
+        let mut location = store_location.clone();
+        location.push(self.get_location());
+
+        File::open(location).and_then(|file| file.unlock())
+    }
+
+}
+
+#[derive(PartialEq, Eq, Debug, Clone)]
+pub enum Action {
+    Lock,
+    Unlock
+}
+
+fn action_to_str(a: &Action) -> &'static str {
+    match a {
+        &Action::Lock   => "lock",
+        &Action::Unlock => "unlock",
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct FlockUpdateHook {
+    action: Action,
+    store_location: PathBuf,
+}
+
+impl FlockUpdateHook {
+
+    pub fn new(action: Action, store_location: PathBuf) -> FlockUpdateHook {
+        FlockUpdateHook {
+            action: action,
+            store_location: store_location,
+        }
+    }
+
+}
+
+impl Hook for FlockUpdateHook {
+
+    fn name(&self) -> &'static str {
+        "stdhook_flock_update"
+    }
+
+    fn set_config(&mut self, _: &Value) {
+        () // We are not configurable here.
+    }
+
+}
+
+impl HookDataAccessorProvider for FlockUpdateHook {
+
+    fn accessor(&self) -> HDA {
+        HDA::StoreIdAccess(self)
+    }
+
+}
+
+impl StoreIdAccessor for FlockUpdateHook {
+
+    fn access(&self, id: &StoreId) -> HookResult<()> {
+        debug!("[FLOCK HOOK][{}] {:?}", action_to_str(&self.action), id);
+        Ok(())
+    }
+
+}
+
+impl MutableHookDataAccessor for FlockUpdateHook {
+
+    fn access_mut(&self, fle: &mut FileLockEntry) -> HookResult<()> {
+        debug!("[FLOCK HOOK][{}] {:?}", action_to_str(&self.action), fle.get_location());
+        fle.lock(&self.store_location)
+            .map_err(|e| HookError::new(HookErrorKind::HookExecutionError, Some(Box::new(e))))
+            .map(|_| ())
+    }
+
+}
+
+impl NonMutableHookDataAccessor for FlockUpdateHook {
+
+    fn access(&self, fle: &FileLockEntry) -> HookResult<()> {
+        debug!("[FLOCK HOOK][{}] {:?}", action_to_str(&self.action), fle.get_location());
+        fle.unlock(&self.store_location)
+            .map_err(|e| HookError::new(HookErrorKind::HookExecutionError, Some(Box::new(e))))
+            .map(|_| ())
+    }
+
+}
+

libimagstorestdhook/src/lib.rs

@@ -16,8 +16,10 @@
 
 #[macro_use] extern crate log;
 extern crate toml;
+extern crate fs2;
 
 extern crate libimagstore;
 
 pub mod debug;
+pub mod flock;