1 files changed, 367 insertions, 0 deletions
diff --git a/toolkit/components/kvstore/src/lib.rs b/toolkit/components/kvstore/src/lib.rs
new file mode 100644
index 0000000000..5601ecb12a
--- /dev/null
+++ b/toolkit/components/kvstore/src/lib.rs
@@ -0,0 +1,367 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+extern crate atomic_refcell;
+extern crate crossbeam_utils;
+#[macro_use]
+extern crate cstr;
+extern crate libc;
+extern crate log;
+extern crate moz_task;
+extern crate nserror;
+extern crate nsstring;
+extern crate rkv;
+extern crate storage_variant;
+extern crate tempfile;
+extern crate thin_vec;
+extern crate thiserror;
+extern crate xpcom;
+
+mod error;
+mod owned_value;
+mod task;
+
+use atomic_refcell::AtomicRefCell;
+use error::KeyValueError;
+use libc::c_void;
+use moz_task::{create_background_task_queue, DispatchOptions, TaskRunnable};
+use nserror::{nsresult, NS_ERROR_FAILURE, NS_OK};
+use nsstring::{nsACString, nsCString};
+use owned_value::{owned_to_variant, variant_to_owned};
+use rkv::backend::{SafeModeDatabase, SafeModeEnvironment};
+use rkv::OwnedValue;
+use std::{
+    ptr,
+    sync::{Arc, RwLock},
+    vec::IntoIter,
+};
+use task::{
+    ClearTask, DeleteTask, EnumerateTask, GetOrCreateTask, GetTask, HasTask, PutTask, WriteManyTask,
+};
+use thin_vec::ThinVec;
+use xpcom::{
+    getter_addrefs,
+    interfaces::{
+        nsIKeyValueDatabaseCallback, nsIKeyValueEnumeratorCallback, nsIKeyValuePair,
+        nsIKeyValueVariantCallback, nsIKeyValueVoidCallback, nsISerialEventTarget, nsIVariant,
+    },
+    nsIID, xpcom, xpcom_method, RefPtr,
+};
+
+type Rkv = rkv::Rkv<SafeModeEnvironment>;
+type SingleStore = rkv::SingleStore<SafeModeDatabase>;
+type KeyValuePairResult = Result<(String, OwnedValue), KeyValueError>;
+
+#[no_mangle]
+pub unsafe extern "C" fn nsKeyValueServiceConstructor(
+    iid: &nsIID,
+    result: *mut *mut c_void,
+) -> nsresult {
+    *result = ptr::null_mut();
+
+    let service = KeyValueService::new();
+    service.QueryInterface(iid, result)
+}
+
+// For each public XPCOM method in the nsIKeyValue* interfaces, we implement
+// a pair of Rust methods:
+//
+//   1. a method named after the XPCOM (as modified by the XPIDL parser, i.e.
+//      by capitalization of its initial letter) that returns an nsresult;
+//
+//   2. a method with a Rust-y name that returns a Result<(), KeyValueError>.
+//
+// XPCOM calls the first method, which is only responsible for calling
+// the second one and converting its Result to an nsresult (logging errors
+// in the process).  The second method is responsible for doing the work.
+//
+// For example, given an XPCOM method FooBar, we implement a method FooBar
+// that calls a method foo_bar.  foo_bar returns a Result<(), KeyValueError>,
+// and FooBar converts that to an nsresult.
+//
+// This design allows us to use Rust idioms like the question mark operator
+// to simplify the implementation in the second method while returning XPCOM-
+// compatible nsresult values to XPCOM callers.
+//
+// The XPCOM methods are implemented using the xpcom_method! declarative macro
+// from the xpcom crate.
+
+#[xpcom(implement(nsIKeyValueService), atomic)]
+pub struct KeyValueService {}
+
+impl KeyValueService {
+    fn new() -> RefPtr<KeyValueService> {
+        KeyValueService::allocate(InitKeyValueService {})
+    }
+
+    xpcom_method!(
+        get_or_create => GetOrCreate(
+            callback: *const nsIKeyValueDatabaseCallback,
+            path: *const nsACString,
+            name: *const nsACString
+        )
+    );
+
+    fn get_or_create(
+        &self,
+        callback: &nsIKeyValueDatabaseCallback,
+        path: &nsACString,
+        name: &nsACString,
+    ) -> Result<(), nsresult> {
+        let task = Box::new(GetOrCreateTask::new(
+            RefPtr::new(callback),
+            nsCString::from(path),
+            nsCString::from(name),
+        ));
+
+        TaskRunnable::new("KVService::GetOrCreate", task)?
+            .dispatch_background_task_with_options(DispatchOptions::default().may_block(true))
+    }
+}
+
+#[xpcom(implement(nsIKeyValueDatabase), atomic)]
+pub struct KeyValueDatabase {
+    rkv: Arc<RwLock<Rkv>>,
+    store: SingleStore,
+    queue: RefPtr<nsISerialEventTarget>,
+}
+
+impl KeyValueDatabase {
+    fn new(
+        rkv: Arc<RwLock<Rkv>>,
+        store: SingleStore,
+    ) -> Result<RefPtr<KeyValueDatabase>, KeyValueError> {
+        let queue = create_background_task_queue(cstr!("KeyValueDatabase"))?;
+        Ok(KeyValueDatabase::allocate(InitKeyValueDatabase {
+            rkv,
+            store,
+            queue,
+        }))
+    }
+
+    xpcom_method!(
+        put => Put(
+            callback: *const nsIKeyValueVoidCallback,
+            key: *const nsACString,
+            value: *const nsIVariant
+        )
+    );
+
+    fn put(
+        &self,
+        callback: &nsIKeyValueVoidCallback,
+        key: &nsACString,
+        value: &nsIVariant,
+    ) -> Result<(), nsresult> {
+        let value = variant_to_owned(value)?.ok_or(KeyValueError::UnexpectedValue)?;
+
+        let task = Box::new(PutTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+            nsCString::from(key),
+            value,
+        ));
+
+        TaskRunnable::dispatch(TaskRunnable::new("KVDatabase::Put", task)?, &self.queue)
+    }
+
+    xpcom_method!(
+        write_many => WriteMany(
+            callback: *const nsIKeyValueVoidCallback,
+            pairs: *const ThinVec<Option<RefPtr<nsIKeyValuePair>>>
+        )
+    );
+
+    fn write_many(
+        &self,
+        callback: &nsIKeyValueVoidCallback,
+        pairs: &ThinVec<Option<RefPtr<nsIKeyValuePair>>>,
+    ) -> Result<(), nsresult> {
+        let mut entries = Vec::with_capacity(pairs.len());
+
+        for pair in pairs {
+            let pair = pair
+                .as_ref()
+                .ok_or(nsresult::from(KeyValueError::UnexpectedValue))?;
+
+            let mut key = nsCString::new();
+            unsafe { pair.GetKey(&mut *key) }.to_result()?;
+            if key.is_empty() {
+                return Err(nsresult::from(KeyValueError::UnexpectedValue));
+            }
+
+            let val: RefPtr<nsIVariant> = getter_addrefs(|p| unsafe { pair.GetValue(p) })?;
+            let value = variant_to_owned(&val)?;
+            entries.push((key, value));
+        }
+
+        let task = Box::new(WriteManyTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+            entries,
+        ));
+
+        TaskRunnable::dispatch(
+            TaskRunnable::new("KVDatabase::WriteMany", task)?,
+            &self.queue,
+        )
+    }
+
+    xpcom_method!(
+        get => Get(
+            callback: *const nsIKeyValueVariantCallback,
+            key: *const nsACString,
+            default_value: *const nsIVariant
+        )
+    );
+
+    fn get(
+        &self,
+        callback: &nsIKeyValueVariantCallback,
+        key: &nsACString,
+        default_value: &nsIVariant,
+    ) -> Result<(), nsresult> {
+        let task = Box::new(GetTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+            nsCString::from(key),
+            variant_to_owned(default_value)?,
+        ));
+
+        TaskRunnable::dispatch(TaskRunnable::new("KVDatabase::Get", task)?, &self.queue)
+    }
+
+    xpcom_method!(
+        has => Has(callback: *const nsIKeyValueVariantCallback, key: *const nsACString)
+    );
+
+    fn has(&self, callback: &nsIKeyValueVariantCallback, key: &nsACString) -> Result<(), nsresult> {
+        let task = Box::new(HasTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+            nsCString::from(key),
+        ));
+
+        TaskRunnable::dispatch(TaskRunnable::new("KVDatabase::Has", task)?, &self.queue)
+    }
+
+    xpcom_method!(
+        delete => Delete(callback: *const nsIKeyValueVoidCallback, key: *const nsACString)
+    );
+
+    fn delete(&self, callback: &nsIKeyValueVoidCallback, key: &nsACString) -> Result<(), nsresult> {
+        let task = Box::new(DeleteTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+            nsCString::from(key),
+        ));
+
+        TaskRunnable::dispatch(TaskRunnable::new("KVDatabase::Delete", task)?, &self.queue)
+    }
+
+    xpcom_method!(
+        clear => Clear(callback: *const nsIKeyValueVoidCallback)
+    );
+
+    fn clear(&self, callback: &nsIKeyValueVoidCallback) -> Result<(), nsresult> {
+        let task = Box::new(ClearTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+        ));
+
+        TaskRunnable::dispatch(TaskRunnable::new("KVDatabase::Clear", task)?, &self.queue)
+    }
+
+    xpcom_method!(
+        enumerate => Enumerate(
+            callback: *const nsIKeyValueEnumeratorCallback,
+            from_key: *const nsACString,
+            to_key: *const nsACString
+        )
+    );
+
+    fn enumerate(
+        &self,
+        callback: &nsIKeyValueEnumeratorCallback,
+        from_key: &nsACString,
+        to_key: &nsACString,
+    ) -> Result<(), nsresult> {
+        let task = Box::new(EnumerateTask::new(
+            RefPtr::new(callback),
+            Arc::clone(&self.rkv),
+            self.store,
+            nsCString::from(from_key),
+            nsCString::from(to_key),
+        ));
+
+        TaskRunnable::dispatch(
+            TaskRunnable::new("KVDatabase::Enumerate", task)?,
+            &self.queue,
+        )
+    }
+}
+
+#[xpcom(implement(nsIKeyValueEnumerator), atomic)]
+pub struct KeyValueEnumerator {
+    iter: AtomicRefCell<IntoIter<KeyValuePairResult>>,
+}
+
+impl KeyValueEnumerator {
+    fn new(pairs: Vec<KeyValuePairResult>) -> RefPtr<KeyValueEnumerator> {
+        KeyValueEnumerator::allocate(InitKeyValueEnumerator {
+            iter: AtomicRefCell::new(pairs.into_iter()),
+        })
+    }
+
+    xpcom_method!(has_more_elements => HasMoreElements() -> bool);
+
+    fn has_more_elements(&self) -> Result<bool, KeyValueError> {
+        Ok(!self.iter.borrow().as_slice().is_empty())
+    }
+
+    xpcom_method!(get_next => GetNext() -> *const nsIKeyValuePair);
+
+    fn get_next(&self) -> Result<RefPtr<nsIKeyValuePair>, KeyValueError> {
+        let mut iter = self.iter.borrow_mut();
+        let (key, value) = iter
+            .next()
+            .ok_or_else(|| KeyValueError::from(NS_ERROR_FAILURE))??;
+
+        // We fail on retrieval of the key/value pair if the key isn't valid
+        // UTF-*, if the value is unexpected, or if we encountered a store error
+        // while retrieving the pair.
+        Ok(RefPtr::new(
+            KeyValuePair::new(key, value).coerce::<nsIKeyValuePair>(),
+        ))
+    }
+}
+
+#[xpcom(implement(nsIKeyValuePair), atomic)]
+pub struct KeyValuePair {
+    key: String,
+    value: OwnedValue,
+}
+
+impl KeyValuePair {
+    fn new(key: String, value: OwnedValue) -> RefPtr<KeyValuePair> {
+        KeyValuePair::allocate(InitKeyValuePair { key, value })
+    }
+
+    xpcom_method!(get_key => GetKey() -> nsACString);
+    xpcom_method!(get_value => GetValue() -> *const nsIVariant);
+
+    fn get_key(&self) -> Result<nsCString, KeyValueError> {
+        Ok(nsCString::from(&self.key))
+    }
+
+    fn get_value(&self) -> Result<RefPtr<nsIVariant>, KeyValueError> {
+        Ok(owned_to_variant(self.value.clone())?)
+    }
+}