Add synchronous callback support to important_file_writer.cc

base/files/important_file_writer_unittest.cc

Index: base/files/important_file_writer_unittest.cc
diff --git a/base/files/important_file_writer_unittest.cc b/base/files/important_file_writer_unittest.cc
index 43e051ebcfadf108e3a244420c5a01d5397396a9..058ec1773e6ac22ee833c35cdd68b6fef3175b9e 100644
--- a/base/files/important_file_writer_unittest.cc
+++ b/base/files/important_file_writer_unittest.cc
@@ -71,7 +71,7 @@ class SuccessfulWriteObserver {
 
 void SuccessfulWriteObserver::ObserveNextSuccessfulWrite(
     ImportantFileWriter* writer) {
-  writer->RegisterOnNextSuccessfulWriteCallback(base::Bind(
+  writer->RegisterOnNextSuccessfulWriteReply(base::Bind(
       &SuccessfulWriteObserver::on_successful_write, base::Unretained(this)));
 }
 
@@ -81,6 +81,54 @@ bool SuccessfulWriteObserver::GetAndResetObservationState() {
   return was_successful_write_observed;
 }
 
+enum WriteCallbackObservationState {
+  NOT_CALLED,
+  CALLED_WITH_ERROR,
+  CALLED_WITH_SUCCESS,
+};
+
+class SynchronousWriteCallbackObserver {
+ public:
+  SynchronousWriteCallbackObserver()
+      : write_callback_observed_(false), write_callback_success_value_(false) {}
+
+  // Register on_write() to be called on the next write of |writer|.
+  void ObserveNextWriteCallback(ImportantFileWriter* writer);
+
+  // Returns true if a write was observed via on_write()
+  // and resets the observation state to false regardless.
+  WriteCallbackObservationState GetAndResetObservationState();
+
+ private:
+  void on_write(bool success) {
+    EXPECT_FALSE(write_callback_observed_);
+    write_callback_observed_ = true;
+    write_callback_success_value_ = success;
+  }
+
+  bool write_callback_observed_;
+  bool write_callback_success_value_;

[gab, 2016/09/01 19:59:53]

Use WriteCallbackObservationState here instead of two bools

[proberge, 2016/09/07 19:07:15]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(SynchronousWriteCallbackObserver);
+};
+
+void SynchronousWriteCallbackObserver::ObserveNextWriteCallback(
+    ImportantFileWriter* writer) {
+  writer->RegisterOnNextWriteSynchronousCallback(base::Bind(
+      &SynchronousWriteCallbackObserver::on_write, base::Unretained(this)));
+}
+
+WriteCallbackObservationState
+SynchronousWriteCallbackObserver::GetAndResetObservationState() {
+  if (write_callback_observed_) {
+    write_callback_observed_ = false;
+    return write_callback_success_value_ ? CALLED_WITH_SUCCESS
+                                         : CALLED_WITH_ERROR;
+  } else {
+    return NOT_CALLED;
+  }
+}
+
 }  // namespace
 
 class ImportantFileWriterTest : public testing::Test {
@@ -93,6 +141,7 @@ class ImportantFileWriterTest : public testing::Test {
 
  protected:
   SuccessfulWriteObserver successful_write_observer_;
+  SynchronousWriteCallbackObserver write_callback_observer_;
   FilePath file_;
   MessageLoop loop_;
 
@@ -104,48 +153,81 @@ TEST_F(ImportantFileWriterTest, Basic) {
   ImportantFileWriter writer(file_, ThreadTaskRunnerHandle::Get());
   EXPECT_FALSE(PathExists(writer.path()));
   EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
   writer.WriteNow(WrapUnique(new std::string("foo")));
   RunLoop().RunUntilIdle();
 
   EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
   ASSERT_TRUE(PathExists(writer.path()));
   EXPECT_EQ("foo", GetFileContent(writer.path()));
 }
 
-TEST_F(ImportantFileWriterTest, BasicWithSuccessfulWriteObserver) {
+TEST_F(ImportantFileWriterTest, BasicWithWriteObservers) {
   ImportantFileWriter writer(file_, ThreadTaskRunnerHandle::Get());
   EXPECT_FALSE(PathExists(writer.path()));
   EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
   successful_write_observer_.ObserveNextSuccessfulWrite(&writer);
+  write_callback_observer_.ObserveNextWriteCallback(&writer);
   writer.WriteNow(WrapUnique(new std::string("foo")));
   RunLoop().RunUntilIdle();
 
-  // Confirm that the observer is invoked.
+  // Confirm that the observers are invoked.
   EXPECT_TRUE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(CALLED_WITH_SUCCESS,
+            write_callback_observer_.GetAndResetObservationState());
   ASSERT_TRUE(PathExists(writer.path()));
   EXPECT_EQ("foo", GetFileContent(writer.path()));
 
-  // Confirm that re-installing the observer works for another write.
+  // Confirm that re-installing the observers works for another write.
   EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
   successful_write_observer_.ObserveNextSuccessfulWrite(&writer);
+  write_callback_observer_.ObserveNextWriteCallback(&writer);
   writer.WriteNow(WrapUnique(new std::string("bar")));
   RunLoop().RunUntilIdle();
 
   EXPECT_TRUE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(CALLED_WITH_SUCCESS,
+            write_callback_observer_.GetAndResetObservationState());
   ASSERT_TRUE(PathExists(writer.path()));
   EXPECT_EQ("bar", GetFileContent(writer.path()));
 
-  // Confirm that writing again without re-installing the observer doesn't
+  // Confirm that writing again without re-installing the observers doesn't
   // result in a notification.
   EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
   writer.WriteNow(WrapUnique(new std::string("baz")));
   RunLoop().RunUntilIdle();
 
   EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
   ASSERT_TRUE(PathExists(writer.path()));
   EXPECT_EQ("baz", GetFileContent(writer.path()));
 }
 
+TEST_F(ImportantFileWriterTest, FailedWriteWithWriteObservers) {
+  // Use an invalid file path to get a FILE_ERROR_ACCESS_DENIED error when
+  // trying to write the file.
+  ImportantFileWriter writer(FilePath().AppendASCII("bad/../path"),
+                             ThreadTaskRunnerHandle::Get());
+  EXPECT_FALSE(PathExists(writer.path()));
+  EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(NOT_CALLED, write_callback_observer_.GetAndResetObservationState());
+  successful_write_observer_.ObserveNextSuccessfulWrite(&writer);
+  write_callback_observer_.ObserveNextWriteCallback(&writer);
+  writer.WriteNow(WrapUnique(new std::string("foo")));
+  RunLoop().RunUntilIdle();
+
+  // Confirm that the successful write observer was not invoked, and that the
+  // write observer was invoked with its boolean parameter set to false.
+  EXPECT_FALSE(successful_write_observer_.GetAndResetObservationState());
+  EXPECT_EQ(CALLED_WITH_ERROR,
+            write_callback_observer_.GetAndResetObservationState());
+  EXPECT_FALSE(PathExists(writer.path()));
+}
+
 TEST_F(ImportantFileWriterTest, ScheduleWrite) {
   ImportantFileWriter writer(file_,
                              ThreadTaskRunnerHandle::Get(),