Blob support for IDB [Chromium]

content/browser/indexed_db/indexed_db_transaction.cc

Index: content/browser/indexed_db/indexed_db_transaction.cc
diff --git a/content/browser/indexed_db/indexed_db_transaction.cc b/content/browser/indexed_db/indexed_db_transaction.cc
index 28f8378f54dfc022e126cbb8897491509dca52c1..5dc02bc2c7b2547e0f23332a002a1ec043685c51 100644
--- a/content/browser/indexed_db/indexed_db_transaction.cc
+++ b/content/browser/indexed_db/indexed_db_transaction.cc
@@ -60,6 +60,7 @@ IndexedDBTransaction::IndexedDBTransaction(
       used_(false),
       state_(CREATED),
       commit_pending_(false),
+      blob_write_success_(false),
       callbacks_(callbacks),
       database_(database),
       transaction_(database->backing_store()),
@@ -95,7 +96,7 @@ void IndexedDBTransaction::ScheduleTask(Operation task, Operation abort_task) {
 
 void IndexedDBTransaction::ScheduleTask(IndexedDBDatabase::TaskType type,
                                         Operation task) {
-  if (state_ == FINISHED)
+  if (IsStatePastRunning())
     return;
 
   used_ = true;
@@ -206,13 +207,37 @@ void IndexedDBTransaction::Start() {
   RunTasksIfStarted();
 }
 
+class BlobWriteCallbackImpl : public IndexedDBBackingStore::BlobWriteCallback {
+ public:
+  BlobWriteCallbackImpl(scoped_refptr<IndexedDBTransaction> transaction)
+      : transaction_(transaction) {}
+  virtual ~BlobWriteCallbackImpl() {}
+  virtual void didSucceed() { transaction_->BlobWriteComplete(true); }

[jsbell, 2013/12/20 00:44:20]

Nit: Chromium naming style

[ericu, 2014/02/20 00:50:29]

Done.

+  virtual void didFail() { transaction_->BlobWriteComplete(false); }
+
+ private:
+  scoped_refptr<IndexedDBTransaction> transaction_;
+};
+
+void IndexedDBTransaction::BlobWriteComplete(bool success) {
+  IDB_TRACE("IndexedDBTransaction::BlobWriteComplete");
+  if (state_ == FINISHED)  // aborted
+    return;
+  DCHECK_EQ(state_, COMMITTING);
+  if (success)
+    CommitPhaseTwo();
+  else
+    Abort(IndexedDBDatabaseError(blink::WebIDBDatabaseExceptionDataError,
+                                 "Failed to write blobs."));
+}
+
 void IndexedDBTransaction::Commit() {
   IDB_TRACE("IndexedDBTransaction::Commit");
 
   // In multiprocess ports, front-end may have requested a commit but
   // an abort has already been initiated asynchronously by the
   // back-end.
-  if (state_ == FINISHED)
+  if (IsStatePastRunning())

[jsbell, 2013/12/20 00:44:20]

Can state_ ever be COMMITTING here? The DCHECK(!used_ || state_ == STARTED)
(below) implies it can't. Commit() should get called:

(1) when the front end signals (exactly once) to commit this transaction - state
should be STARTED or FINISHED (if aborted)

(2) there were pending tasks (i.e. index population), which caused a commit
request from the front end to bail (see HasPendingTasks() call)

[ericu, 2014/02/20 00:50:29]

You're right that it shouldn't ever happen.  However, we could get here if a
malicious or malfunctioning renderer sent an extra commit during blob write. 
Returning seems like the safe thing to do; I'll add an extra DCHECK to make it
clear that state_ should be FINISHED.

     return;
 
   DCHECK(!used_ || state_ == STARTED);
@@ -224,6 +249,24 @@ void IndexedDBTransaction::Commit() {
   if (HasPendingTasks())
     return;
 
+  state_ = COMMITTING;
+
+  if (!used_)
+    CommitPhaseTwo();
+  else {
+    scoped_refptr<IndexedDBBackingStore::BlobWriteCallback> callback(
+        new BlobWriteCallbackImpl(this));
+    // CommitPhaseOne will call the callback synchronously if there are no blobs
+    // to write.
+    if (!transaction_.CommitPhaseOne(callback))
+      Abort(IndexedDBDatabaseError(blink::WebIDBDatabaseExceptionDataError,
+                                   "Error processing blob journal."));
+  }
+}
+
+void IndexedDBTransaction::CommitPhaseTwo() {
+  DCHECK_EQ(state_, COMMITTING);
+
   // The last reference to this object may be released while performing the
   // commit steps below. We therefore take a self reference to keep ourselves
   // alive while executing this method.
@@ -234,7 +277,7 @@ void IndexedDBTransaction::Commit() {
 
   state_ = FINISHED;
 
-  bool committed = !used_ || transaction_.Commit();
+  bool committed = !used_ || transaction_.CommitPhaseTwo();
 
   // Backing store resources (held via cursors) must be released
   // before script callbacks are fired, as the script callbacks may
@@ -286,8 +329,8 @@ void IndexedDBTransaction::ProcessTaskQueue() {
 
   TaskQueue* task_queue =
       pending_preemptive_events_ ? &preemptive_task_queue_ : &task_queue_;
-  while (!task_queue->empty() && state_ != FINISHED) {
-    DCHECK_EQ(STARTED, state_);
+  while (!task_queue->empty() && !IsStatePastRunning()) {
+    DCHECK_EQ(state_, STARTED);
     Operation task(task_queue->pop());
     task.Run(this);
     if (!pending_preemptive_events_) {
@@ -302,7 +345,7 @@ void IndexedDBTransaction::ProcessTaskQueue() {
 
   // If there are no pending tasks, we haven't already committed/aborted,
   // and the front-end requested a commit, it is now safe to do so.
-  if (!HasPendingTasks() && state_ != FINISHED && commit_pending_)
+  if (!HasPendingTasks() && !IsStatePastRunning() && commit_pending_)

[jsbell, 2013/12/20 00:44:20]

FYI, if you rebase, a test will appear below this line: if (state_ == FINISHED)
return; that should probably change to IsStatePastRunning() too.

[ericu, 2014/02/20 00:50:29]

Hmm...I'm not sure about that one.  It looks like a check for "did we abort",
which would only be FINISHED.  Is there a way to start committing while
processing the task queue?

[jsbell, 2014/02/20 22:55:50]

There shouldn't be; commit_pending_ should only be settable via IPC from the
renderer to the IDB thread, which must wait 'til this returns to the message
loop.

     Commit();
 }