Bug 988301 - Avoid main-thread IO in Sync code. r=Yoric, r=rnewman

services/sync/modules/policies.js

@@ -13,6 +13,8 @@ Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-sync/constants.js");
 Cu.import("resource://services-sync/engines.js");
 Cu.import("resource://services-sync/util.js");
+Cu.import("resource://gre/modules/FileUtils.jsm");
+Cu.import("resource://gre/modules/NetUtil.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "Status",
                                   "resource://services-sync/status.js");

services/sync/modules/util.js

@@ -2,8 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-this.EXPORTED_SYMBOLS = ["XPCOMUtils", "Services", "NetUtil",
-                         "FileUtils", "Utils", "Async", "Svc", "Str"];
+this.EXPORTED_SYMBOLS = ["XPCOMUtils", "Services", "Utils", "Async", "Svc", "Str"];
 
 const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
 
@@ -14,11 +13,11 @@ Cu.import("resource://services-common/utils.js");
 Cu.import("resource://services-common/async.js", this);
 Cu.import("resource://services-crypto/utils.js");
 Cu.import("resource://services-sync/constants.js");
-Cu.import("resource://gre/modules/FileUtils.jsm", this);
-Cu.import("resource://gre/modules/NetUtil.jsm", this);
 Cu.import("resource://gre/modules/Preferences.jsm");
 Cu.import("resource://gre/modules/Services.jsm", this);
 Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
+Cu.import("resource://gre/modules/osfile.jsm", this);
+Cu.import("resource://gre/modules/Task.jsm", this);
 
 /*
  * Utility functions
@@ -337,41 +336,28 @@ this.Utils = {
    *        Function to process json object as its first argument. If the file
    *        could not be loaded, the first argument will be undefined.
    */
-  jsonLoad: function jsonLoad(filePath, that, callback) {
-    let path = "weave/" + filePath + ".json";
+  jsonLoad: Task.async(function*(filePath, that, callback) {
+    let path = OS.Path.join(OS.Constants.Path.profileDir, "weave", filePath + ".json");
 
     if (that._log) {
       that._log.trace("Loading json from disk: " + filePath);
     }
 
-    let file = FileUtils.getFile("ProfD", path.split("/"), true);
-    if (!file.exists()) {
-      callback.call(that);
-      return;
+    let json;
+
+    try {
+      json = yield CommonUtils.readJSON(path);
+    } catch (e if e instanceof OS.File.Error && e.becauseNoSuchFile) {
+      // Ignore non-existent files.
+    } catch (e) {
+      if (that._log) {
+        that._log.debug("Failed to load json: " +
+                        CommonUtils.exceptionStr(e));
+      }
     }
 
-    let channel = NetUtil.newChannel(file);
-    channel.contentType = "application/json";
-
-    NetUtil.asyncFetch(channel, function (is, result) {
-      if (!Components.isSuccessCode(result)) {
-        callback.call(that);
-        return;
-      }
-      let string = NetUtil.readInputStreamToString(is, is.available());
-      is.close();
-      let json;
-      try {
-        json = JSON.parse(string);
-      } catch (ex) {
-        if (that._log) {
-          that._log.debug("Failed to load json: " +
-                          CommonUtils.exceptionStr(ex));
-        }
-      }
-      callback.call(that, json);
-    });
-  },
+    callback.call(that, json);
+  }),
 
   /**
    * Save a json-able object to disk in the profile directory.
@@ -389,25 +375,27 @@ this.Utils = {
    *        constant on error or null if no error was encountered (and
    *        the file saved successfully).
    */
-  jsonSave: function jsonSave(filePath, that, obj, callback) {
-    let path = "weave/" + filePath + ".json";
-    if (that._log) {
-      that._log.trace("Saving json to disk: " + path);
-    }
+  jsonSave: Task.async(function*(filePath, that, obj, callback) {
+    let path = OS.Path.join(OS.Constants.Path.profileDir, "weave",
+                            ...(filePath + ".json").split("/"));
+    let dir = OS.Path.dirname(path);
+    let error = null;
 
-    let file = FileUtils.getFile("ProfD", path.split("/"), true);
-    let json = typeof obj == "function" ? obj.call(that) : obj;
-    let out = JSON.stringify(json);
+    try {
+      yield OS.File.makeDir(dir, { from: OS.Constants.Path.profileDir });
 
-    let fos = FileUtils.openSafeFileOutputStream(file);
-    let is = this._utf8Converter.convertToInputStream(out);
-    NetUtil.asyncCopy(is, fos, function (result) {
-      if (typeof callback == "function") {
-        let error = (result == Cr.NS_OK) ? null : result;
-        callback.call(that, error);
+      if (that._log) {
+        that._log.trace("Saving json to disk: " + path);
       }
-    });
-  },
+
+      let json = typeof obj == "function" ? obj.call(that) : obj;
+
+      yield CommonUtils.writeJSON(json, path);
+    } catch (e) {
+      error = e
+    }
+    callback.call(that, error);
+  }),
 
   getErrorString: function Utils_getErrorString(error, args) {
     try {

services/sync/tests/unit/test_errorhandler.js

@@ -10,6 +10,7 @@ Cu.import("resource://services-sync/service.js");
 Cu.import("resource://services-sync/status.js");
 Cu.import("resource://services-sync/util.js");
 Cu.import("resource://testing-common/services/sync/utils.js");
+Cu.import("resource://gre/modules/FileUtils.jsm");
 
 const FAKE_SERVER_URL = "http://dummy:9000/";
 const logsdir = FileUtils.getDir("ProfD", ["weave", "logs"], true);

services/sync/tests/unit/test_errorhandler_filelog.js

@@ -5,6 +5,8 @@ Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-common/utils.js");
 Cu.import("resource://services-sync/service.js");
 Cu.import("resource://services-sync/util.js");
+Cu.import("resource://gre/modules/FileUtils.jsm");
+Cu.import("resource://gre/modules/NetUtil.jsm");
 
 const logsdir            = FileUtils.getDir("ProfD", ["weave", "logs"], true);
 const LOG_PREFIX_SUCCESS = "success-";