Cache feedback reports to disk in case of send failure.

chrome/browser/feedback/feedback_report.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/feedback/feedback_report.h"
+
+#include "base/file_util.h"
+#include "base/files/file_enumerator.h"
+#include "base/files/important_file_writer.h"
+#include "base/guid.h"
+#include "base/strings/string_number_conversions.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/base/directory_lister.h"
+
+using content::BrowserThread;
+
+namespace {
+
+const base::FilePath::CharType kFeedbackReportPath[] =
+    FILE_PATH_LITERAL("Feedback Reports");
+const base::FilePath::CharType kFeedbackReportFilenameWildcard[] =
+    FILE_PATH_LITERAL("Feedback Report.*");
+
+const char kFeedbackReportFilenamePrefix[] = "Feedback Report.";
+
+base::FilePath GetFeedbackReportsPath(content::BrowserContext* context) {
+  if (!context)
+    return base::FilePath();
+  return context->GetPath().Append(kFeedbackReportPath);
+}
+
+}  // namespace
+
+namespace feedback {
+
+FeedbackReport::FeedbackReport(content::BrowserContext* context,
+                               const base::Time& upload_at,
+                               const std::string& data)
+    : upload_at_(upload_at),
+      data_(data) {
+  reports_path_ = GetFeedbackReportsPath(context);
+  if (reports_path_.empty())
+    return;
+  file_ = reports_path_.AppendASCII(
+      kFeedbackReportFilenamePrefix + base::GenerateGUID());

[Lei Zhang, 2014/02/01 01:37:22]

Consider using file_util::GetUniquePathNumber() instead of GenerateGUID().

[rkc, 2014/02/03 22:13:11]

That would involve moving getting the filename onto the blocking pool (since
GetUniquePathNumber interacts with the file system). I really want to have the
filename here itself and using GenerateGUID does the job.

+  BrowserThread::PostBlockingPoolTask(FROM_HERE, base::Bind(
+      &FeedbackReport::WriteReportOnBlockingPool, this));
+}
+
+FeedbackReport::~FeedbackReport() {}
+
+void FeedbackReport::DeleteReportOnDisk() {
+  BrowserThread::PostBlockingPoolTask(FROM_HERE, base::Bind(
+      &FeedbackReport::DeleteReportOnBlockingPool, this));
+}
+
+void FeedbackReport::WriteReportOnBlockingPool() {
+  base::AutoLock locker(file_access_lock_);
+  if (file_.empty())
+    return;
+
+  if (!base::DirectoryExists(reports_path_)) {
+    base::File::Error error;
+    if (!base::CreateDirectoryAndGetError(reports_path_, &error))
+      return;
+  }
+  base::ImportantFileWriter::WriteFileAtomically(file_, data_);
+}
+
+void FeedbackReport::DeleteReportOnBlockingPool() {
+  base::AutoLock locker(file_access_lock_);

[Lei Zhang, 2014/02/01 01:37:22]

You shouldn't need a lock. Instead, get a SequenceToken and use that token
whenever you PostTask() to the blocking pool.

[rkc, 2014/02/03 22:13:11]

Done.

+  DeleteFile(file_, false);
+  file_.clear();
+}
+
+// static
+void FeedbackReport::LoadReportsAndQueue(
+    content::BrowserContext* context, QueueCallback callback) {
+  base::FilePath reports_path = GetFeedbackReportsPath(context);
+  if (reports_path.empty())
+    return;
+
+  base::FileEnumerator enumerator(reports_path,
+                                  false,
+                                  base::FileEnumerator::FILES,
+                                  kFeedbackReportFilenameWildcard);
+  for (base::FilePath name = enumerator.Next();
+       !name.empty();
+       name = enumerator.Next()) {
+    std::string data;
+    if (ReadFileToString(name, &data))
+      BrowserThread::PostTask(
+          BrowserThread::UI, FROM_HERE, base::Bind(callback, data));
+    base::DeleteFile(name, false);
+  }
+}
+
+}  // namespace feedback