Bug 1368567 - Remove useless main-thread IO from XUL store; r=florian

toolkit/components/xulstore/XULStore.js

@@ -65,10 +65,11 @@ XULStore.prototype = {
     this._storeFile = Services.dirsvc.get("ProfD", Ci.nsIFile);
     this._storeFile.append(STOREDB_FILENAME);
 
-    if (!this._storeFile.exists()) {
-      this.import();
-    } else {
+    try {
       this.readFile();
+    } catch (e) {
+      // If readFile() throws, it means that the file didn't exist.
+      this.import();
     }
   },
 
@@ -93,9 +94,6 @@ XULStore.prototype = {
     let localStoreFile = Services.dirsvc.get("ProfD", Ci.nsIFile);
 
     localStoreFile.append("localstore.rdf");
-    if (!localStoreFile.exists()) {
-      return;
-    }
 
     const RDF = Cc["@mozilla.org/rdf/rdf-service;1"].getService(Ci.nsIRDFService);
     const persistKey = RDF.GetResource("http://home.netscape.com/NC-rdf#persist");
@@ -153,7 +151,9 @@ XULStore.prototype = {
       this._data = json.decodeFromStream(stream, stream.available());
     } catch (e) {
       this.log("Error reading JSON: " + e);
-      // Ignore problem, we'll just continue on with an empty dataset.
+      if (e.result == Cr.NS_ERROR_FILE_NOT_FOUND) {
+        throw e; // Let the caller handle it!
+      }
     } finally {
       stream.close();
     }

toolkit/components/xulstore/tests/xpcshell/head.js

@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/◦
+*/
+
+"use strict"
+
+function checkValue(uri, id, attr, reference) {
+  let value = XULStore.getValue(uri, id, attr);
+  do_check_eq(value, reference);
+}
+
+function checkValueExists(uri, id, attr, exists) {
+  do_check_eq(XULStore.hasValue(uri, id, attr), exists);
+}
+
+function getIDs(uri) {
+  let it = XULStore.getIDsEnumerator(uri);
+  let result = [];
+
+  while (it.hasMore()) {
+    let value = it.getNext();
+    result.push(value);
+  }
+
+  result.sort();
+  return result;
+}
+
+function getAttributes(uri, id) {
+  let it = XULStore.getAttributeEnumerator(uri, id);
+
+  let result = [];
+
+  while (it.hasMore()) {
+    let value = it.getNext();
+    result.push(value);
+  }
+
+  result.sort();
+  return result;
+}
+
+function checkArrays(a, b) {
+  a.sort();
+  b.sort();
+  do_check_true(a.toString() == b.toString());
+}
+

toolkit/components/xulstore/tests/xpcshell/test_XULStore.js

@@ -20,48 +20,6 @@ function run_test() {
   run_next_test();
 }
 
-function checkValue(uri, id, attr, reference) {
-  let value = XULStore.getValue(uri, id, attr);
-  do_check_true(value === reference);
-}
-
-function checkValueExists(uri, id, attr, exists) {
-  do_check_eq(XULStore.hasValue(uri, id, attr), exists);
-}
-
-function getIDs(uri) {
-  let it = XULStore.getIDsEnumerator(uri);
-  let result = [];
-
-  while (it.hasMore()) {
-    let value = it.getNext();
-    result.push(value);
-  }
-
-  result.sort();
-  return result;
-}
-
-function getAttributes(uri, id) {
-  let it = XULStore.getAttributeEnumerator(uri, id);
-
-  let result = [];
-
-  while (it.hasMore()) {
-    let value = it.getNext();
-    result.push(value);
-  }
-
-  result.sort();
-  return result;
-}
-
-function checkArrays(a, b) {
-  a.sort();
-  b.sort();
-  do_check_true(a.toString() == b.toString());
-}
-
 function checkOldStore() {
   checkArrays(["addon-bar", "main-window", "sidebar-title"], getIDs(browserURI));
   checkArrays(["collapsed"], getAttributes(browserURI, "addon-bar"));

toolkit/components/xulstore/tests/xpcshell/test_XULStoreImportWithoutPreExistingLocalStoreRDF.js

@@ -0,0 +1,50 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/◦
+*/
+
+"use strict"
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+const Cr = Components.results;
+
+Cu.import("resource://gre/modules/osfile.jsm")
+
+var XULStore = null;
+var browserURI = "chrome://browser/content/browser.xul";
+var aboutURI = "about:config";
+
+function run_test() {
+  do_get_profile();
+  run_next_test();
+}
+
+function checkOldStore() {
+  checkArrays([], getIDs(browserURI));
+  checkArrays([], getAttributes(browserURI, "addon-bar"));
+  checkArrays([],
+              getAttributes(browserURI, "main-window"));
+  checkArrays([], getAttributes(browserURI, "sidebar-title"));
+
+  checkValue(browserURI, "addon-bar", "collapsed", "");
+  checkValue(browserURI, "main-window", "width", "");
+  checkValue(browserURI, "main-window", "height", "");
+  checkValue(browserURI, "main-window", "screenX", "");
+  checkValue(browserURI, "main-window", "screenY", "");
+  checkValue(browserURI, "main-window", "sizemode", "");
+  checkValue(browserURI, "sidebar-title", "value", "");
+
+  checkArrays([], getIDs(aboutURI));
+  checkArrays([], getAttributes(aboutURI, "lockCol"));
+  checkArrays([], getAttributes(aboutURI, "prefCol"));
+
+  checkValue(aboutURI, "prefCol", "ordinal", "");
+  checkValue(aboutURI, "prefCol", "sortDirection", "");
+  checkValue(aboutURI, "lockCol", "ordinal", "");
+}
+
+add_task(async function testImportWithoutPreExistingLocalStoreRDF() {
+  XULStore = Cc["@mozilla.org/xul/xulstore;1"].getService(Ci.nsIXULStore);
+  checkOldStore();
+});

toolkit/components/xulstore/tests/xpcshell/xpcshell.ini

@@ -1,6 +1,8 @@
 [DEFAULT]
+head = head.js
 skip-if = toolkit == 'android'
 support-files =
   localstore.rdf
 
 [test_XULStore.js]
+[test_XULStoreImportWithoutPreExistingLocalStoreRDF.js]