1 files changed, 130 insertions, 0 deletions
diff --git a/chrome/common/json_pref_store.cc b/chrome/common/json_pref_store.cc
new file mode 100644
index 0000000..9acfcb2
--- /dev/null
+++ b/chrome/common/json_pref_store.cc
@@ -0,0 +1,130 @@
+// Copyright (c) 2010 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/common/json_pref_store.h"
+
+#include <algorithm>
+
+#include "base/file_util.h"
+#include "base/values.h"
+#include "chrome/common/json_value_serializer.h"
+
+namespace {
+
+// Some extensions we'll tack on to copies of the Preferences files.
+const FilePath::CharType* kBadExtension = FILE_PATH_LITERAL("bad");
+
+}  // namespace
+
+JsonPrefStore::JsonPrefStore(const FilePath& filename,
+                             base::MessageLoopProxy* file_message_loop_proxy)
+    : path_(filename),
+      prefs_(new DictionaryValue()),
+      read_only_(false),
+      writer_(filename, file_message_loop_proxy) {
+}
+
+JsonPrefStore::~JsonPrefStore() {
+  if (writer_.HasPendingWrite() && !read_only_)
+    writer_.DoScheduledWrite();
+}
+
+PrefStore::PrefReadError JsonPrefStore::ReadPrefs() {
+  JSONFileValueSerializer serializer(path_);
+
+  int error_code = 0;
+  std::string error_msg;
+  scoped_ptr<Value> value(serializer.Deserialize(&error_code, &error_msg));
+  if (!value.get()) {
+#if defined(GOOGLE_CHROME_BUILD)
+    // This log could be used for more detailed client-side error diagnosis,
+    // but since this triggers often with unit tests, we need to disable it
+    // in non-official builds.
+    PLOG(ERROR) << "Error reading Preferences: " << error_msg << " " <<
+        path_.value();
+#endif
+    PrefReadError error;
+    switch (error_code) {
+      case JSONFileValueSerializer::JSON_ACCESS_DENIED:
+        // If the file exists but is simply unreadable, put the file into a
+        // state where we don't try to save changes.  Otherwise, we could
+        // clobber the existing prefs.
+        error = PREF_READ_ERROR_ACCESS_DENIED;
+        read_only_ = true;
+        break;
+      case JSONFileValueSerializer::JSON_CANNOT_READ_FILE:
+        error = PREF_READ_ERROR_FILE_OTHER;
+        read_only_ = true;
+        break;
+      case JSONFileValueSerializer::JSON_FILE_LOCKED:
+        error = PREF_READ_ERROR_FILE_LOCKED;
+        read_only_ = true;
+        break;
+      case JSONFileValueSerializer::JSON_NO_SUCH_FILE:
+        // If the file just doesn't exist, maybe this is first run.  In any case
+        // there's no harm in writing out default prefs in this case.
+        error = PREF_READ_ERROR_NO_FILE;
+        break;
+      default:
+        error = PREF_READ_ERROR_JSON_PARSE;
+        // JSON errors indicate file corruption of some sort.
+        // Since the file is corrupt, move it to the side and continue with
+        // empty preferences.  This will result in them losing their settings.
+        // We keep the old file for possible support and debugging assistance
+        // as well as to detect if they're seeing these errors repeatedly.
+        // TODO(erikkay) Instead, use the last known good file.
+        FilePath bad = path_.ReplaceExtension(kBadExtension);
+
+        // If they've ever had a parse error before, put them in another bucket.
+        // TODO(erikkay) if we keep this error checking for very long, we may
+        // want to differentiate between recent and long ago errors.
+        if (file_util::PathExists(bad))
+          error = PREF_READ_ERROR_JSON_REPEAT;
+        file_util::Move(path_, bad);
+        break;
+    }
+    return error;
+  }
+
+  // Preferences should always have a dictionary root.
+  if (!value->IsType(Value::TYPE_DICTIONARY)) {
+    // See comment for the default case above.
+    read_only_ = true;
+    return PREF_READ_ERROR_JSON_TYPE;
+  }
+
+  prefs_.reset(static_cast<DictionaryValue*>(value.release()));
+
+  return PREF_READ_ERROR_NONE;
+}
+
+bool JsonPrefStore::WritePrefs() {
+  std::string data;
+  if (!SerializeData(&data))
+    return false;
+
+  // Lie about our ability to save.
+  if (read_only_)
+    return true;
+
+  writer_.WriteNow(data);
+  return true;
+}
+
+void JsonPrefStore::ScheduleWritePrefs() {
+  if (read_only_)
+    return;
+
+  writer_.ScheduleWrite(this);
+}
+
+bool JsonPrefStore::SerializeData(std::string* output) {
+  // TODO(tc): Do we want to prune webkit preferences that match the default
+  // value?
+  JSONStringValueSerializer serializer(output);
+  serializer.set_pretty_print(true);
+  scoped_ptr<DictionaryValue> copy(prefs_->DeepCopyWithoutEmptyChildren());
+  return serializer.Serialize(*(copy.get()));
+}
+