Original patch by rlarocque@chromium.org at http://codereview.chromium.org/7633077/

chrome/browser/sync/internal_api/write_node.cc

+// Copyright (c) 2011 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/sync/internal_api/write_node.h"
+
+#include "base/json/json_writer.h"
+#include "base/utf_string_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/sync/engine/nigori_util.h"
+#include "chrome/browser/sync/engine/syncapi_internal.h"
+#include "chrome/browser/sync/internal_api/base_transaction.h"
+#include "chrome/browser/sync/internal_api/write_transaction.h"
+#include "chrome/browser/sync/protocol/app_specifics.pb.h"
+#include "chrome/browser/sync/protocol/autofill_specifics.pb.h"
+#include "chrome/browser/sync/protocol/bookmark_specifics.pb.h"
+#include "chrome/browser/sync/protocol/extension_specifics.pb.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+#include "chrome/browser/sync/protocol/session_specifics.pb.h"
+#include "chrome/browser/sync/protocol/theme_specifics.pb.h"
+#include "chrome/browser/sync/protocol/typed_url_specifics.pb.h"
+#include "chrome/browser/sync/syncable/syncable.h"
+#include "chrome/browser/sync/util/cryptographer.h"
+
+using browser_sync::Cryptographer;
+using std::string;
+using std::vector;
+using syncable::kEncryptedString;
+using syncable::SPECIFICS;
+
+namespace sync_api {
+
+static const char kDefaultNameForNewNodes[] = " ";
+
+//////////////////////////////////////////////////////////////////////////
+// Static helper functions.
+
+// When taking a name from the syncapi, append a space if it matches the
+// pattern of a server-illegal name followed by zero or more spaces.
+static void SyncAPINameToServerName(const std::wstring& sync_api_name,
+                                    std::string* out) {
+  *out = WideToUTF8(sync_api_name);
+  if (IsNameServerIllegalAfterTrimming(*out))
+    out->append(" ");
+}
+
+bool WriteNode::UpdateEntryWithEncryption(
+    browser_sync::Cryptographer* cryptographer,
+    const sync_pb::EntitySpecifics& new_specifics,
+    syncable::MutableEntry* entry) {
+  syncable::ModelType type = syncable::GetModelTypeFromSpecifics(new_specifics);
+  DCHECK_GE(type, syncable::FIRST_REAL_MODEL_TYPE);
+  syncable::ModelTypeSet encrypted_types = cryptographer->GetEncryptedTypes();
+
+  sync_pb::EntitySpecifics generated_specifics;
+  if (type == syncable::PASSWORDS ||        // Has own encryption scheme.
+      type == syncable::NIGORI ||           // Encrypted separately.
+      encrypted_types.count(type) == 0 ||
+      new_specifics.has_encrypted()) {
+    // No encryption required.
+    generated_specifics.CopyFrom(new_specifics);
+  } else {
+    // Encrypt new_specifics into generated_specifics.
+    if (VLOG_IS_ON(2)) {
+      scoped_ptr<DictionaryValue> value(entry->ToValue());
+      std::string info;
+      base::JSONWriter::Write(value.get(), true, &info);
+      VLOG(2) << "Encrypting specifics of type "
+              << syncable::ModelTypeToString(type)
+              << " with content: "
+              << info;
+    }
+    if (!cryptographer->is_initialized())
+      return false;
+    syncable::AddDefaultExtensionValue(type, &generated_specifics);
+    if (!cryptographer->Encrypt(new_specifics,
+                                generated_specifics.mutable_encrypted())) {
+      NOTREACHED() << "Could not encrypt data for node of type "
+                   << syncable::ModelTypeToString(type);
+      return false;
+    }
+  }
+
+  const sync_pb::EntitySpecifics& old_specifics = entry->Get(SPECIFICS);
+  if (AreSpecificsEqual(cryptographer, old_specifics, generated_specifics)) {
+    // Even if the data is the same but the old specifics are encrypted with an
+    // old key, we should go ahead and re-encrypt with the new key.
+    if ((!old_specifics.has_encrypted() &&
+         !generated_specifics.has_encrypted()) ||
+         cryptographer->CanDecryptUsingDefaultKey(old_specifics.encrypted())) {
+      VLOG(2) << "Specifics of type " << syncable::ModelTypeToString(type)
+              << " already match, dropping change.";
+      return true;
+    }
+    // TODO(zea): Add some way to keep track of how often we're reencrypting
+    // because of a passphrase change.
+  }
+
+  if (generated_specifics.has_encrypted()) {
+    // Overwrite the possibly sensitive non-specifics data.
+    entry->Put(syncable::NON_UNIQUE_NAME, kEncryptedString);
+    // For bookmarks we actually put bogus data into the unencrypted specifics,
+    // else the server will try to do it for us.
+    if (type == syncable::BOOKMARKS) {
+      sync_pb::BookmarkSpecifics* bookmark_specifics =
+          generated_specifics.MutableExtension(sync_pb::bookmark);
+      if (!entry->Get(syncable::IS_DIR))
+        bookmark_specifics->set_url(kEncryptedString);
+      bookmark_specifics->set_title(kEncryptedString);
+    }
+  }
+  entry->Put(syncable::SPECIFICS, generated_specifics);
+  syncable::MarkForSyncing(entry);
+  return true;
+}
+
+void WriteNode::SetIsFolder(bool folder) {
+  if (entry_->Get(syncable::IS_DIR) == folder)
+    return;  // Skip redundant changes.
+
+  entry_->Put(syncable::IS_DIR, folder);
+  MarkForSyncing();
+}
+
+void WriteNode::SetTitle(const std::wstring& title) {
+  std::string server_legal_name;
+  SyncAPINameToServerName(title, &server_legal_name);
+
+  string old_name = entry_->Get(syncable::NON_UNIQUE_NAME);
+
+  if (server_legal_name == old_name)
+    return;  // Skip redundant changes.
+
+  // Only set NON_UNIQUE_NAME to the title if we're not encrypted.
+  if (GetEntitySpecifics().has_encrypted())
+    entry_->Put(syncable::NON_UNIQUE_NAME, kEncryptedString);
+  else
+    entry_->Put(syncable::NON_UNIQUE_NAME, server_legal_name);
+
+  // For bookmarks, we also set the title field in the specifics.
+  // TODO(zea): refactor bookmarks to not need this functionality.
+  if (GetModelType() == syncable::BOOKMARKS) {
+    sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
+    new_value.set_title(server_legal_name);
+    SetBookmarkSpecifics(new_value);  // Does it's own encryption checking.
+  }
+
+  MarkForSyncing();
+}
+
+void WriteNode::SetURL(const GURL& url) {
+  sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
+  new_value.set_url(url.spec());
+  SetBookmarkSpecifics(new_value);
+}
+
+void WriteNode::SetAppSpecifics(
+    const sync_pb::AppSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::app)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetAutofillSpecifics(
+    const sync_pb::AutofillSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::autofill)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetAutofillProfileSpecifics(
+    const sync_pb::AutofillProfileSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::autofill_profile)->
+      CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetBookmarkSpecifics(
+    const sync_pb::BookmarkSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::bookmark)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetNigoriSpecifics(
+    const sync_pb::NigoriSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::nigori)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetPasswordSpecifics(
+    const sync_pb::PasswordSpecificsData& data) {
+  DCHECK_EQ(syncable::PASSWORDS, GetModelType());
+
+  Cryptographer* cryptographer = GetTransaction()->GetCryptographer();
+
+  // Idempotency check to prevent unnecessary syncing: if the plaintexts match
+  // and the old ciphertext is encrypted with the most current key, there's
+  // nothing to do here.  Because each encryption is seeded with a different
+  // random value, checking for equivalence post-encryption doesn't suffice.
+  const sync_pb::EncryptedData& old_ciphertext =
+      GetEntry()->Get(SPECIFICS).GetExtension(sync_pb::password).encrypted();
+  scoped_ptr<sync_pb::PasswordSpecificsData> old_plaintext(
+      DecryptPasswordSpecifics(GetEntry()->Get(SPECIFICS), cryptographer));
+  if (old_plaintext.get() &&
+      old_plaintext->SerializeAsString() == data.SerializeAsString() &&
+      cryptographer->CanDecryptUsingDefaultKey(old_ciphertext)) {
+    return;
+  }
+
+  sync_pb::PasswordSpecifics new_value;
+  if (!cryptographer->Encrypt(data, new_value.mutable_encrypted())) {
+    NOTREACHED() << "Failed to encrypt password, possibly due to sync node "
+                 << "corruption";
+    return;
+  }
+
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::password)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetThemeSpecifics(
+    const sync_pb::ThemeSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::theme)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetSessionSpecifics(
+    const sync_pb::SessionSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::session)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetEntitySpecifics(
+    const sync_pb::EntitySpecifics& new_value) {
+  syncable::ModelType new_specifics_type =
+      syncable::GetModelTypeFromSpecifics(new_value);
+  DCHECK_NE(new_specifics_type, syncable::UNSPECIFIED);
+  VLOG(1) << "Writing entity specifics of type "
+          << syncable::ModelTypeToString(new_specifics_type);
+  // GetModelType() can be unspecified if this is the first time this
+  // node is being initialized (see PutModelType()).  Otherwise, it
+  // should match |new_specifics_type|.
+  if (GetModelType() != syncable::UNSPECIFIED) {
+    DCHECK_EQ(new_specifics_type, GetModelType());
+  }
+  browser_sync::Cryptographer* cryptographer =
+      GetTransaction()->GetCryptographer();
+
+  // Preserve unknown fields.
+  const sync_pb::EntitySpecifics& old_specifics = entry_->Get(SPECIFICS);
+  sync_pb::EntitySpecifics new_specifics;
+  new_specifics.CopyFrom(new_value);
+  new_specifics.mutable_unknown_fields()->MergeFrom(
+      old_specifics.unknown_fields());
+
+  // Will update the entry if encryption was necessary.
+  if (!UpdateEntryWithEncryption(cryptographer, new_specifics, entry_)) {
+    return;
+  }
+  if (entry_->Get(SPECIFICS).has_encrypted()) {
+    // EncryptIfNecessary already updated the entry for us and marked for
+    // syncing if it was needed. Now we just make a copy of the unencrypted
+    // specifics so that if this node is updated, we do not have to decrypt the
+    // old data. Note that this only modifies the node's local data, not the
+    // entry itself.
+    SetUnencryptedSpecifics(new_value);
+  }
+
+  DCHECK_EQ(new_specifics_type, GetModelType());
+}
+
+void WriteNode::ResetFromSpecifics() {
+  SetEntitySpecifics(GetEntitySpecifics());
+}
+
+void WriteNode::SetTypedUrlSpecifics(
+    const sync_pb::TypedUrlSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::typed_url)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetExtensionSpecifics(
+    const sync_pb::ExtensionSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.MutableExtension(sync_pb::extension)->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
+void WriteNode::SetExternalId(int64 id) {
+  if (GetExternalId() != id)
+    entry_->Put(syncable::LOCAL_EXTERNAL_ID, id);
+}
+
+WriteNode::WriteNode(WriteTransaction* transaction)
+    : entry_(NULL), transaction_(transaction) {
+  DCHECK(transaction);
+}
+
+WriteNode::~WriteNode() {
+  delete entry_;
+}
+
+// Find an existing node matching the ID |id|, and bind this WriteNode to it.
+// Return true on success.
+bool WriteNode::InitByIdLookup(int64 id) {
+  DCHECK(!entry_) << "Init called twice";
+  DCHECK_NE(id, kInvalidId);
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_HANDLE, id);
+  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
+          DecryptIfNecessary());
+}
+
+// Find a node by client tag, and bind this WriteNode to it.
+// Return true if the write node was found, and was not deleted.
+// Undeleting a deleted node is possible by ClientTag.
+bool WriteNode::InitByClientTagLookup(syncable::ModelType model_type,
+                                      const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+
+  const std::string hash = GenerateSyncableHash(model_type, tag);
+
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_CLIENT_TAG, hash);
+  return (entry_->good() && !entry_->Get(syncable::IS_DEL) &&
+          DecryptIfNecessary());
+}
+
+bool WriteNode::InitByTagLookup(const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+  if (tag.empty())
+    return false;
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::GET_BY_SERVER_TAG, tag);
+  if (!entry_->good())
+    return false;
+  if (entry_->Get(syncable::IS_DEL))
+    return false;
+  syncable::ModelType model_type = GetModelType();
+  DCHECK_EQ(syncable::NIGORI, model_type);
+  return true;
+}
+
+void WriteNode::PutModelType(syncable::ModelType model_type) {
+  // Set an empty specifics of the appropriate datatype.  The presence
+  // of the specific extension will identify the model type.
+  DCHECK(GetModelType() == model_type ||
+         GetModelType() == syncable::UNSPECIFIED);  // Immutable once set.
+
+  sync_pb::EntitySpecifics specifics;
+  syncable::AddDefaultExtensionValue(model_type, &specifics);
+  SetEntitySpecifics(specifics);
+}
+
+// Create a new node with default properties, and bind this WriteNode to it.
+// Return true on success.
+bool WriteNode::InitByCreation(syncable::ModelType model_type,
+                               const BaseNode& parent,
+                               const BaseNode* predecessor) {
+  DCHECK(!entry_) << "Init called twice";
+  // |predecessor| must be a child of |parent| or NULL.
+  if (predecessor && predecessor->GetParentId() != parent.GetId()) {
+    DCHECK(false);
+    return false;
+  }
+
+  syncable::Id parent_id = parent.GetEntry()->Get(syncable::ID);
+
+  // Start out with a dummy name.  We expect
+  // the caller to set a meaningful name after creation.
+  string dummy(kDefaultNameForNewNodes);
+
+  entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                      syncable::CREATE, parent_id, dummy);
+
+  if (!entry_->good())
+    return false;
+
+  // Entries are untitled folders by default.
+  entry_->Put(syncable::IS_DIR, true);
+
+  PutModelType(model_type);
+
+  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
+  PutPredecessor(predecessor);
+
+  return true;
+}
+
+// Create a new node with default properties and a client defined unique tag,
+// and bind this WriteNode to it.
+// Return true on success. If the tag exists in the database, then
+// we will attempt to undelete the node.
+// TODO(chron): Code datatype into hash tag.
+// TODO(chron): Is model type ever lost?
+bool WriteNode::InitUniqueByCreation(syncable::ModelType model_type,
+                                     const BaseNode& parent,
+                                     const std::string& tag) {
+  DCHECK(!entry_) << "Init called twice";
+
+  const std::string hash = GenerateSyncableHash(model_type, tag);
+
+  syncable::Id parent_id = parent.GetEntry()->Get(syncable::ID);
+
+  // Start out with a dummy name.  We expect
+  // the caller to set a meaningful name after creation.
+  string dummy(kDefaultNameForNewNodes);
+
+  // Check if we have this locally and need to undelete it.
+  scoped_ptr<syncable::MutableEntry> existing_entry(
+      new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                 syncable::GET_BY_CLIENT_TAG, hash));
+
+  if (existing_entry->good()) {
+    if (existing_entry->Get(syncable::IS_DEL)) {
+      // Rules for undelete:
+      // BASE_VERSION: Must keep the same.
+      // ID: Essential to keep the same.
+      // META_HANDLE: Must be the same, so we can't "split" the entry.
+      // IS_DEL: Must be set to false, will cause reindexing.
+      //         This one is weird because IS_DEL is true for "update only"
+      //         items. It should be OK to undelete an update only.
+      // MTIME/CTIME: Seems reasonable to just leave them alone.
+      // IS_UNSYNCED: Must set this to true or face database insurrection.
+      //              We do this below this block.
+      // IS_UNAPPLIED_UPDATE: Either keep it the same or also set BASE_VERSION
+      //                      to SERVER_VERSION. We keep it the same here.
+      // IS_DIR: We'll leave it the same.
+      // SPECIFICS: Reset it.
+
+      existing_entry->Put(syncable::IS_DEL, false);
+
+      // Client tags are immutable and must be paired with the ID.
+      // If a server update comes down with an ID and client tag combo,
+      // and it already exists, always overwrite it and store only one copy.
+      // We have to undelete entries because we can't disassociate IDs from
+      // tags and updates.
+
+      existing_entry->Put(syncable::NON_UNIQUE_NAME, dummy);
+      existing_entry->Put(syncable::PARENT_ID, parent_id);
+      entry_ = existing_entry.release();
+    } else {
+      return false;
+    }
+  } else {
+    entry_ = new syncable::MutableEntry(transaction_->GetWrappedWriteTrans(),
+                                        syncable::CREATE, parent_id, dummy);
+    if (!entry_->good()) {
+      return false;
+    }
+
+    // Only set IS_DIR for new entries. Don't bitflip undeleted ones.
+    entry_->Put(syncable::UNIQUE_CLIENT_TAG, hash);
+  }
+
+  // We don't support directory and tag combinations.
+  entry_->Put(syncable::IS_DIR, false);
+
+  // Will clear specifics data.
+  PutModelType(model_type);
+
+  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
+  PutPredecessor(NULL);
+
+  return true;
+}
+
+bool WriteNode::SetPosition(const BaseNode& new_parent,
+                            const BaseNode* predecessor) {
+  // |predecessor| must be a child of |new_parent| or NULL.
+  if (predecessor && predecessor->GetParentId() != new_parent.GetId()) {
+    DCHECK(false);
+    return false;
+  }
+
+  syncable::Id new_parent_id = new_parent.GetEntry()->Get(syncable::ID);
+
+  // Filter out redundant changes if both the parent and the predecessor match.
+  if (new_parent_id == entry_->Get(syncable::PARENT_ID)) {
+    const syncable::Id& old = entry_->Get(syncable::PREV_ID);
+    if ((!predecessor && old.IsRoot()) ||
+        (predecessor && (old == predecessor->GetEntry()->Get(syncable::ID)))) {
+      return true;
+    }
+  }
+
+  // Atomically change the parent. This will fail if it would
+  // introduce a cycle in the hierarchy.
+  if (!entry_->Put(syncable::PARENT_ID, new_parent_id))
+    return false;
+
+  // Now set the predecessor, which sets IS_UNSYNCED as necessary.
+  PutPredecessor(predecessor);
+
+  return true;
+}
+
+const syncable::Entry* WriteNode::GetEntry() const {
+  return entry_;
+}
+
+const BaseTransaction* WriteNode::GetTransaction() const {
+  return transaction_;
+}
+
+void WriteNode::Remove() {
+  entry_->Put(syncable::IS_DEL, true);
+  MarkForSyncing();
+}
+
+void WriteNode::PutPredecessor(const BaseNode* predecessor) {
+  syncable::Id predecessor_id = predecessor ?
+      predecessor->GetEntry()->Get(syncable::ID) : syncable::Id();
+  entry_->PutPredecessor(predecessor_id);
+  // Mark this entry as unsynced, to wake up the syncer.
+  MarkForSyncing();
+}
+
+void WriteNode::SetFaviconBytes(const vector<unsigned char>& bytes) {
+  sync_pb::BookmarkSpecifics new_value = GetBookmarkSpecifics();
+  new_value.set_favicon(bytes.empty() ? NULL : &bytes[0], bytes.size());
+  SetBookmarkSpecifics(new_value);
+}
+
+void WriteNode::MarkForSyncing() {
+  syncable::MarkForSyncing(entry_);
+}
+
+} // namespace sync_api