Android WebView save/restoreState and backForardList Part 1

android_webview/native/state_serializer.cc

+// Copyright (c) 2012 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 "android_webview/native/state_serializer.h"
+
+#include <string>
+
+#include "base/memory/scoped_vector.h"
+#include "base/pickle.h"
+#include "base/time.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/navigation_entry.h"
+#include "content/public/browser/web_contents.h"
+
+// Reasons for not re-using TabNavigation under chrome/ as of 20121116:
+// * Android WebView has different requirements for fields to store since
+//   we are the only ones using values like BaseURLForDataURL.
+// * TabNavigation does unnecessary copying of data, which in Android
+//   WebView case, is undesired since save/restore is called in Android
+//   very frequently.
+// * TabNavigation is tightly integrated with the rest of chrome session
+//   restore and sync code, and has other purpose in addition to serializing
+//   NavigationEntry.
+
+using std::string;
+
+namespace android_webview {
+
+namespace {
+
+// Sanity check value that we are restoring from a valid pickle.
+// This can potentially used as an actual serialization version number in the
+// future if we ever decide to support restoring from older versions.
+const uint32 AW_STATE_VERSION = 20121116;
+
+}  // namespace
+
+bool WriteToPickle(const content::WebContents& web_contents,
+                   Pickle* pickle) {
+  DCHECK(pickle);
+
+  if (!internal::WriteHeaderToPickle(pickle))
+    return false;
+
+  const content::NavigationController& controller =
+      web_contents.GetController();
+  const int entry_count = controller.GetEntryCount();
+  const int selected_entry = controller.GetCurrentEntryIndex();
+  DCHECK(entry_count >= 0);
+  DCHECK(selected_entry >= -1);  // -1 is valid
+  DCHECK(selected_entry < entry_count);
+
+  if (!pickle->WriteInt(entry_count))
+    return false;
+
+  if (!pickle->WriteInt(selected_entry))
+    return false;
+
+  for (int i = 0; i < entry_count; ++i) {
+    if (!internal::WriteNavigationEntryToPickle(*controller.GetEntryAtIndex(i),
+                                                pickle))
+      return false;
+  }
+
+  // Please update AW_STATE_VERSION if serialization format is changed.
+
+  return true;
+}
+
+bool RestoreFromPickle(PickleIterator* iterator,
+                       content::WebContents* web_contents) {
+  DCHECK(iterator);
+  DCHECK(web_contents);
+
+  if (!internal::RestoreHeaderFromPickle(iterator))
+    return false;
+
+  int entry_count = -1;
+  int selected_entry = -2;  // -1 is a valid value
+
+  if (!iterator->ReadInt(&entry_count))
+    return false;
+
+  if (!iterator->ReadInt(&selected_entry))
+    return false;
+
+  if (entry_count < 0)
+    return false;
+  if (selected_entry < -1)
+    return false;
+  if (selected_entry >= entry_count)
+    return false;
+
+  ScopedVector<content::NavigationEntry> restored_entries;
+  for (int i = 0; i < entry_count; ++i) {
+    restored_entries.push_back(content::NavigationEntry::Create());
+    if (!internal::RestoreNavigationEntryFromPickle(iterator,
+                                                    restored_entries[i]))
+      return false;
+  }
+
+  // |web_contents| takes ownership of these entries after this call.
+  web_contents->GetController().Restore(
+      selected_entry,
+      content::NavigationController::RESTORE_LAST_SESSION_EXITED_CLEANLY,
+      &restored_entries.get());
+  DCHECK_EQ(0u, restored_entries.size());
+
+  return true;
+}
+
+namespace internal {
+
+bool WriteHeaderToPickle(Pickle* pickle) {
+  return pickle->WriteUInt32(AW_STATE_VERSION);
+}
+
+bool RestoreHeaderFromPickle(PickleIterator* iterator) {
+  uint32 state_version = -1;
+  if (!iterator->ReadUInt32(&state_version))
+    return false;
+
+  if (AW_STATE_VERSION != state_version)
+    return false;
+
+  return true;
+}
+
+bool WriteNavigationEntryToPickle(const content::NavigationEntry& entry,
+                                  Pickle* pickle) {
+  if (!pickle->WriteString(entry.GetURL().spec()))
+    return false;
+
+  if (!pickle->WriteString(entry.GetVirtualURL().spec()))
+    return false;
+
+  const content::Referrer& referrer = entry.GetReferrer();
+  if (!pickle->WriteString(referrer.url.spec()))
+    return false;
+  if (!pickle->WriteInt(static_cast<int>(referrer.policy)))
+    return false;
+
+  if (!pickle->WriteString16(entry.GetTitle()))
+    return false;
+
+  if (!pickle->WriteString(entry.GetContentState()))
+    return false;
+
+  if (!pickle->WriteBool(static_cast<int>(entry.GetHasPostData())))
+    return false;
+
+  if (!pickle->WriteString(entry.GetOriginalRequestURL().spec()))
+    return false;
+
+  if (!pickle->WriteBool(static_cast<int>(entry.GetIsOverridingUserAgent())))
+    return false;
+
+  if (!pickle->WriteInt64(entry.GetTimestamp().ToInternalValue()))
+    return false;
+
+  // Please update AW_STATE_VERSION if serialization format is changed.
+
+  return true;
+}
+
+bool RestoreNavigationEntryFromPickle(PickleIterator* iterator,
+                                      content::NavigationEntry* entry) {
+  {
+    string url;
+    if (!iterator->ReadString(&url))
+      return false;
+    entry->SetURL(GURL(url));
+  }
+
+  {
+    string virtual_url;
+    if (!iterator->ReadString(&virtual_url))
+      return false;
+    entry->SetVirtualURL(GURL(virtual_url));
+  }
+
+  {
+    content::Referrer referrer;
+    string referrer_url;
+    int policy;
+
+    if (!iterator->ReadString(&referrer_url))
+      return false;
+    if (!iterator->ReadInt(&policy))
+      return false;
+
+    referrer.url = GURL(referrer_url);
+    referrer.policy = static_cast<WebKit::WebReferrerPolicy>(policy);
+    entry->SetReferrer(referrer);
+  }
+
+  {
+    string16 title;
+    if (!iterator->ReadString16(&title))
+      return false;
+    entry->SetTitle(title);
+  }
+
+  {
+    string content_state;
+    if (!iterator->ReadString(&content_state))
+      return false;
+    entry->SetContentState(content_state);
+  }
+
+  {
+    bool has_post_data;
+    if (!iterator->ReadBool(&has_post_data))
+      return false;
+    entry->SetHasPostData(has_post_data);
+  }
+
+  {
+    string original_request_url;
+    if (!iterator->ReadString(&original_request_url))
+      return false;
+    entry->SetOriginalRequestURL(GURL(original_request_url));
+  }
+
+  {
+    bool is_overriding_user_agent;
+    if (!iterator->ReadBool(&is_overriding_user_agent))
+      return false;
+    entry->SetIsOverridingUserAgent(is_overriding_user_agent);
+  }
+
+  {
+    int64 timestamp;
+    if (!iterator->ReadInt64(&timestamp))
+      return false;
+    entry->SetTimestamp(base::Time::FromInternalValue(timestamp));
+  }
+
+  return true;
+}
+
+}  // namespace internal
+
+}  // namespace android_webview