Refactor syncapi.h

chrome/browser/sync/internal_api/sync_manager.h

+// 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.
+
+#ifndef CHROME_BROWSER_SYNC_INTERNAL_API_SYNC_MANAGER_H_
+#define CHROME_BROWSER_SYNC_INTERNAL_API_SYNC_MANAGER_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/callback_old.h"
+#include "base/memory/linked_ptr.h"
+#include "chrome/browser/sync/engine/configure_reason.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+#include "chrome/browser/sync/syncable/model_type.h"
+#include "chrome/browser/sync/weak_handle.h"
+#include "chrome/common/net/gaia/google_service_auth_error.h"
+
+class FilePath;
+
+namespace base {
+class DictionaryValue;
+}  // namespace base
+
+namespace browser_sync {
+class JsBackend;
+class JsEventHandler;
+class ModelSafeWorkerRegistrar;
+
+namespace sessions {
+struct SyncSessionSnapshot;
+}  // namespace sessions
+}  // namespace browser_sync
+
+namespace sync_notifier {
+class SyncNotifier;
+}  // namespace sync_notifier
+
+namespace sync_pb {
+class PasswordSpecificsData;
+}  // namespace sync_pb
+
+namespace sync_api {
+
+class BaseTransaction;
+class HttpPostProviderFactory;
+class UserShare;
+
+// Reasons due to which browser_sync::Cryptographer might require a passphrase.
+enum PassphraseRequiredReason {
+  REASON_PASSPHRASE_NOT_REQUIRED = 0,  // Initial value.
+  REASON_ENCRYPTION = 1,               // The cryptographer requires a
+                                       // passphrase for its first attempt at
+                                       // encryption. Happens only during
+                                       // migration or upgrade.
+  REASON_DECRYPTION = 2,               // The cryptographer requires a
+                                       // passphrase for its first attempt at
+                                       // decryption.
+  REASON_SET_PASSPHRASE_FAILED = 3,    // The cryptographer requires a new
+                                       // passphrase because its attempt at
+                                       // decryption with the cached passphrase
+                                       // was unsuccessful.
+};
+
+// Contains everything needed to talk to and identify a user account.
+struct SyncCredentials {
+  std::string email;
+  std::string sync_token;
+};
+
+// SyncManager encapsulates syncable::DirectoryManager and serves as the parent
+// of all other objects in the sync API.  SyncManager is thread-safe.  If
+// multiple threads interact with the same local sync repository (i.e. the
+// same sqlite database), they should share a single SyncManager instance.  The
+// caller should typically create one SyncManager for the lifetime of a user
+// session.
+class SyncManager {
+ public:
+  // SyncInternal contains the implementation of SyncManager, while abstracting
+  // internal types from clients of the interface.
+  class SyncInternal;
+
+  // TODO(zea): One day get passwords playing nicely with the rest of encryption
+  // and get rid of this.
+  class ExtraPasswordChangeRecordData {
+   public:
+    ExtraPasswordChangeRecordData();
+    explicit ExtraPasswordChangeRecordData(
+        const sync_pb::PasswordSpecificsData& data);
+    virtual ~ExtraPasswordChangeRecordData();
+
+    // Transfers ownership of the DictionaryValue to the caller.
+    virtual base::DictionaryValue* ToValue() const;
+
+    const sync_pb::PasswordSpecificsData& unencrypted() const;
+   private:
+    sync_pb::PasswordSpecificsData unencrypted_;
+  };
+
+  // ChangeRecord indicates a single item that changed as a result of a sync
+  // operation.  This gives the sync id of the node that changed, and the type
+  // of change.  To get the actual property values after an ADD or UPDATE, the
+  // client should get the node with InitByIdLookup(), using the provided id.
+  struct ChangeRecord {
+    enum Action {
+      ACTION_ADD,
+      ACTION_DELETE,
+      ACTION_UPDATE,
+    };
+    ChangeRecord();
+    ~ChangeRecord();
+
+    // Transfers ownership of the DictionaryValue to the caller.
+    base::DictionaryValue* ToValue(const BaseTransaction* trans) const;
+
+    int64 id;
+    Action action;
+    sync_pb::EntitySpecifics specifics;
+    linked_ptr<ExtraPasswordChangeRecordData> extra;
+  };
+
+  // Status encapsulates detailed state about the internals of the SyncManager.
+  struct Status {
+    // Summary is a distilled set of important information that the end-user may
+    // wish to be informed about (through UI, for example). Note that if a
+    // summary state requires user interaction (such as auth failures), more
+    // detailed information may be contained in additional status fields.
+    enum Summary {
+      // The internal instance is in an unrecognizable state. This should not
+      // happen.
+      INVALID = 0,
+      // Can't connect to server, but there are no pending changes in
+      // our local cache.
+      OFFLINE,
+      // Can't connect to server, and there are pending changes in our
+      // local cache.
+      OFFLINE_UNSYNCED,
+      // Connected and syncing.
+      SYNCING,
+      // Connected, no pending changes.
+      READY,
+      // Internal sync error.
+      CONFLICT,
+      // Can't connect to server, and we haven't completed the initial
+      // sync yet.  So there's nothing we can do but wait for the server.
+      OFFLINE_UNUSABLE,
+
+      SUMMARY_STATUS_COUNT,
+    };
+
+    Status();
+    ~Status();
+
+    Summary summary;
+    bool authenticated;      // Successfully authenticated via GAIA.
+    bool server_up;          // True if we have received at least one good
+                             // reply from the server.
+    bool server_reachable;   // True if we received any reply from the server.
+    bool server_broken;      // True of the syncer is stopped because of server
+                             // issues.
+    bool notifications_enabled;  // True only if subscribed for notifications.
+
+    // Notifications counters updated by the actions in synapi.
+    int notifications_received;
+    int notifiable_commits;
+
+    // The max number of consecutive errors from any component.
+    int max_consecutive_errors;
+
+    int unsynced_count;
+
+    int conflicting_count;
+    bool syncing;
+    // True after a client has done a first sync.
+    bool initial_sync_ended;
+    // True if any syncer is stuck.
+    bool syncer_stuck;
+
+    // Total updates available.  If zero, nothing left to download.
+    int64 updates_available;
+    // Total updates received by the syncer since browser start.
+    int updates_received;
+
+    // Of updates_received, how many were tombstones.
+    int tombstone_updates_received;
+    bool disk_full;
+
+    // Total number of overwrites due to conflict resolver since browser start.
+    int num_local_overwrites_total;
+    int num_server_overwrites_total;
+
+    // Count of empty and non empty getupdates;
+    int nonempty_get_updates;
+    int empty_get_updates;
+
+    // Count of useless and useful syncs we perform.
+    int useless_sync_cycles;
+    int useful_sync_cycles;
+
+    // Encryption related.
+    syncable::ModelTypeSet encrypted_types;
+    bool cryptographer_ready;
+    bool crypto_has_pending_keys;
+  };
+
+  // An interface the embedding application implements to receive notifications
+  // from the SyncManager.  Register an observer via SyncManager::AddObserver.
+  // This observer is an event driven model as the events may be raised from
+  // different internal threads, and simply providing an "OnStatusChanged" type
+  // notification complicates things such as trying to determine "what changed",
+  // if different members of the Status object are modified from different
+  // threads.  This way, the event is explicit, and it is safe for the Observer
+  // to dispatch to a native thread or synchronize accordingly.
+  class Observer {
+   public:
+    // Notify the observer that changes have been applied to the sync model.
+    //
+    // This will be invoked on the same thread as on which ApplyChanges was
+    // called. |changes| is an array of size |change_count|, and contains the
+    // ID of each individual item that was changed. |changes| exists only for
+    // the duration of the call. If items of multiple data types change at
+    // the same time, this method is invoked once per data type and |changes|
+    // is restricted to items of the ModelType indicated by |model_type|.
+    // Because the observer is passed a |trans|, the observer can assume a
+    // read lock on the sync model that will be released after the function
+    // returns.
+    //
+    // The SyncManager constructs |changes| in the following guaranteed order:
+    //
+    // 1. Deletions, from leaves up to parents.
+    // 2. Updates to existing items with synced parents & predecessors.
+    // 3. New items with synced parents & predecessors.
+    // 4. Items with parents & predecessors in |changes|.
+    // 5. Repeat #4 until all items are in |changes|.
+    //
+    // Thus, an implementation of OnChangesApplied should be able to
+    // process the change records in the order without having to worry about
+    // forward dependencies.  But since deletions come before reparent
+    // operations, a delete may temporarily orphan a node that is
+    // updated later in the list.
+    virtual void OnChangesApplied(syncable::ModelType model_type,
+                                  const BaseTransaction* trans,
+                                  const ChangeRecord* changes,
+                                  int change_count) = 0;
+
+    // OnChangesComplete gets called when the TransactionComplete event is
+    // posted (after OnChangesApplied finishes), after the transaction lock
+    // and the change channel mutex are released.
+    //
+    // The purpose of this function is to support processors that require
+    // split-transactions changes. For example, if a model processor wants to
+    // perform blocking I/O due to a change, it should calculate the changes
+    // while holding the transaction lock (from within OnChangesApplied), buffer
+    // those changes, let the transaction fall out of scope, and then commit
+    // those changes from within OnChangesComplete (postponing the blocking
+    // I/O to when it no longer holds any lock).
+    virtual void OnChangesComplete(syncable::ModelType model_type) = 0;
+
+    // A round-trip sync-cycle took place and the syncer has resolved any
+    // conflicts that may have arisen.
+    virtual void OnSyncCycleCompleted(
+        const browser_sync::sessions::SyncSessionSnapshot* snapshot) = 0;
+
+    // Called when user interaction may be required due to an auth problem.
+    virtual void OnAuthError(const GoogleServiceAuthError& auth_error) = 0;
+
+    // Called when a new auth token is provided by the sync server.
+    virtual void OnUpdatedToken(const std::string& token) = 0;
+
+    // Called when user interaction is required to obtain a valid passphrase.
+    // - If the passphrase is required for encryption, |reason| will be
+    //   REASON_ENCRYPTION.
+    // - If the passphrase is required for the decryption of data that has
+    //   already been encrypted, |reason| will be REASON_DECRYPTION.
+    // - If the passphrase is required because decryption failed, and a new
+    //   passphrase is required, |reason| will be REASON_SET_PASSPHRASE_FAILED.
+    virtual void OnPassphraseRequired(PassphraseRequiredReason reason) = 0;
+
+    // Called when the passphrase provided by the user has been accepted and is
+    // now used to encrypt sync data.  |bootstrap_token| is an opaque base64
+    // encoded representation of the key generated by the accepted passphrase,
+    // and is provided to the observer for persistence purposes and use in a
+    // future initialization of sync (e.g. after restart).
+    virtual void OnPassphraseAccepted(const std::string& bootstrap_token) = 0;
+
+    // Called when initialization is complete to the point that SyncManager can
+    // process changes. This does not necessarily mean authentication succeeded
+    // or that the SyncManager is online.
+    // IMPORTANT: Creating any type of transaction before receiving this
+    // notification is illegal!
+    // WARNING: Calling methods on the SyncManager before receiving this
+    // message, unless otherwise specified, produces undefined behavior.
+    //
+    // |js_backend| is what about:sync interacts with.  It can emit
+    // the following events:
+
+    /**
+     * @param {{ enabled: boolean }} details A dictionary containing:
+     *     - enabled: whether or not notifications are enabled.
+     */
+    // function onNotificationStateChange(details);
+
+    /**
+     * @param {{ changedTypes: Array.<string> }} details A dictionary
+     *     containing:
+     *     - changedTypes: a list of types (as strings) for which there
+             are new updates.
+     */
+    // function onIncomingNotification(details);
+
+    // Also, it responds to the following messages (all other messages
+    // are ignored):
+
+    /**
+     * Gets the current notification state.
+     *
+     * @param {function(boolean)} callback Called with whether or not
+     *     notifications are enabled.
+     */
+    // function getNotificationState(callback);
+
+    /**
+     * Gets details about the root node.
+     *
+     * @param {function(!Object)} callback Called with details about the
+     *     root node.
+     */
+    // TODO(akalin): Change this to getRootNodeId or eliminate it
+    // entirely.
+    // function getRootNodeDetails(callback);
+
+    /**
+     * Gets summary information for a list of ids.
+     *
+     * @param {Array.<string>} idList List of 64-bit ids in decimal
+     *     string form.
+     * @param {Array.<{id: string, title: string, isFolder: boolean}>}
+     * callback Called with summaries for the nodes in idList that
+     *     exist.
+     */
+    // function getNodeSummariesById(idList, callback);
+
+    /**
+     * Gets detailed information for a list of ids.
+     *
+     * @param {Array.<string>} idList List of 64-bit ids in decimal
+     *     string form.
+     * @param {Array.<!Object>} callback Called with detailed
+     *     information for the nodes in idList that exist.
+     */
+    // function getNodeDetailsById(idList, callback);
+
+    /**
+     * Gets child ids for a given id.
+     *
+     * @param {string} id 64-bit id in decimal string form of the parent
+     *     node.
+     * @param {Array.<string>} callback Called with the (possibly empty)
+     *     list of child ids.
+     */
+    // function getChildNodeIds(id);
+
+    virtual void OnInitializationComplete(
+        const browser_sync::WeakHandle<browser_sync::JsBackend>&
+            js_backend) = 0;
+
+    // We are no longer permitted to communicate with the server. Sync should
+    // be disabled and state cleaned up at once.  This can happen for a number
+    // of reasons, e.g. swapping from a test instance to production, or a
+    // global stop syncing operation has wiped the store.
+    virtual void OnStopSyncingPermanently() = 0;
+
+    // After a request to clear server data, these callbacks are invoked to
+    // indicate success or failure.
+    virtual void OnClearServerDataSucceeded() = 0;
+    virtual void OnClearServerDataFailed() = 0;
+
+    // Called after we finish encrypting all appropriate datatypes.
+    virtual void OnEncryptionComplete(
+        const syncable::ModelTypeSet& encrypted_types) = 0;
+
+   protected:
+    virtual ~Observer();
+  };
+
+  typedef Callback0::Type ModeChangeCallback;
+
+  // Create an uninitialized SyncManager.  Callers must Init() before using.
+  explicit SyncManager(const std::string& name);
+  virtual ~SyncManager();
+
+  // Initialize the sync manager.  |database_location| specifies the path of
+  // the directory in which to locate a sqlite repository storing the syncer
+  // backend state. Initialization will open the database, or create it if it
+  // does not already exist. Returns false on failure.
+  // |event_handler| is the JsEventHandler used to propagate events to
+  // chrome://sync-internals.  |event_handler| may be uninitialized.
+  // |sync_server_and_path| and |sync_server_port| represent the Chrome sync
+  // server to use, and |use_ssl| specifies whether to communicate securely;
+  // the default is false.
+  // |post_factory| will be owned internally and used to create
+  // instances of an HttpPostProvider.
+  // |model_safe_worker| ownership is given to the SyncManager.
+  // |user_agent| is a 7-bit ASCII string suitable for use as the User-Agent
+  // HTTP header. Used internally when collecting stats to classify clients.
+  // |sync_notifier| is owned and used to listen for notifications.
+  bool Init(const FilePath& database_location,
+            const browser_sync::WeakHandle<browser_sync::JsEventHandler>&
+                event_handler,
+            const std::string& sync_server_and_path,
+            int sync_server_port,
+            bool use_ssl,
+            HttpPostProviderFactory* post_factory,
+            browser_sync::ModelSafeWorkerRegistrar* registrar,
+            const std::string& user_agent,
+            const SyncCredentials& credentials,
+            sync_notifier::SyncNotifier* sync_notifier,
+            const std::string& restored_key_for_bootstrapping,
+            bool setup_for_test_mode);
+
+  // Returns the username last used for a successful authentication.
+  // Returns empty if there is no such username.
+  const std::string& GetAuthenticatedUsername();
+
+  // Check if the database has been populated with a full "initial" download of
+  // sync items for each data type currently present in the routing info.
+  // Prerequisite for calling this is that OnInitializationComplete has been
+  // called.
+  bool InitialSyncEndedForAllEnabledTypes();
+
+  // Update tokens that we're using in Sync. Email must stay the same.
+  void UpdateCredentials(const SyncCredentials& credentials);
+
+  // Called when the user disables or enables a sync type.
+  void UpdateEnabledTypes();
+
+  // Put the syncer in normal mode ready to perform nudges and polls.
+  void StartSyncingNormally();
+
+  // Attempt to set the passphrase. If the passphrase is valid,
+  // OnPassphraseAccepted will be fired to notify the ProfileSyncService and the
+  // syncer will be nudged so that any update that was waiting for this
+  // passphrase gets applied as soon as possible.
+  // If the passphrase in invalid, OnPassphraseRequired will be fired.
+  // Calling this metdod again is the appropriate course of action to "retry"
+  // with a new passphrase.
+  // |is_explicit| is true if the call is in response to the user explicitly
+  // setting a passphrase as opposed to implicitly (from the users' perspective)
+  // using their Google Account password.  An implicit SetPassphrase will *not*
+  // *not* override an explicit passphrase set previously.
+  void SetPassphrase(const std::string& passphrase, bool is_explicit);
+
+  // Set the datatypes we want to encrypt and encrypt any nodes as necessary.
+  // Note: |encrypted_types| will be unioned with the current set of encrypted
+  // types, as we do not currently support decrypting datatypes.
+  void EncryptDataTypes(const syncable::ModelTypeSet& encrypted_types);
+
+  // Puts the SyncScheduler into a mode where no normal nudge or poll traffic
+  // will occur, but calls to RequestConfig will be supported.  If |callback|
+  // is provided, it will be invoked (from the internal SyncScheduler) when
+  // the thread has changed to configuration mode.
+  void StartConfigurationMode(ModeChangeCallback* callback);
+
+  // Switches the mode of operation to CONFIGURATION_MODE and
+  // schedules a config task to fetch updates for |types|.
+  void RequestConfig(const syncable::ModelTypeBitSet& types,
+     sync_api::ConfigureReason reason);
+
+  void RequestCleanupDisabledTypes();
+
+  // Request a clearing of all data on the server
+  void RequestClearServerData();
+
+  // Adds a listener to be notified of sync events.
+  // NOTE: It is OK (in fact, it's probably a good idea) to call this before
+  // having received OnInitializationCompleted.
+  void AddObserver(Observer* observer);
+
+  // Remove the given observer.  Make sure to call this if the
+  // Observer is being destroyed so the SyncManager doesn't
+  // potentially dereference garbage.
+  void RemoveObserver(Observer* observer);
+
+  // Status-related getters. Typically GetStatusSummary will suffice, but
+  // GetDetailedSyncStatus can be useful for gathering debug-level details of
+  // the internals of the sync engine.
+  Status::Summary GetStatusSummary() const;
+  Status GetDetailedStatus() const;
+
+  // Whether or not the Nigori node is encrypted using an explicit passphrase.
+  bool IsUsingExplicitPassphrase();
+
+  // Get the internal implementation for use by BaseTransaction, etc.
+  SyncInternal* GetImpl() const;
+
+  // Call periodically from a database-safe thread to persist recent changes
+  // to the syncapi model.
+  void SaveChanges();
+
+  void RequestEarlyExit();
+
+  // Issue a final SaveChanges, close sqlite handles, and stop running threads.
+  // Must be called from the same thread that called Init().
+  void Shutdown();
+
+  UserShare* GetUserShare() const;
+
+  // Inform the cryptographer of the most recent passphrase and set of encrypted
+  // types (from nigori node), then ensure all data that needs encryption is
+  // encrypted with the appropriate passphrase.
+  // Note: opens a transaction and can trigger ON_PASSPHRASE_REQUIRED, so must
+  // only be called after syncapi has been initialized.
+  void RefreshEncryption();
+
+  syncable::ModelTypeSet GetEncryptedDataTypes() const;
+
+  // Uses a read-only transaction to determine if the directory being synced has
+  // any remaining unsynced items.
+  bool HasUnsyncedItems() const;
+
+  // Logs the list of unsynced meta handles.
+  void LogUnsyncedItems(int level) const;
+
+  // Functions used for testing.
+
+  void TriggerOnNotificationStateChangeForTest(
+      bool notifications_enabled);
+
+  void TriggerOnIncomingNotificationForTest(
+      const syncable::ModelTypeBitSet& model_types);
+
+ private:
+  // An opaque pointer to the nested private class.
+  SyncInternal* data_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncManager);
+};
+
+bool InitialSyncEndedForTypes(syncable::ModelTypeSet types, UserShare* share);
+
+// Returns the string representation of a PassphraseRequiredReason value.
+std::string PassphraseRequiredReasonToString(PassphraseRequiredReason reason);
+
+} // namespace sync_api
+
+#endif  // CHROME_BROWSER_SYNC_INTERNAL_API_SYNC_MANAGER_H_