feat(caching): #630 replace data when ready as opposed to invalidatin…

…g first

lib/ActivityStreams.js

@@ -187,7 +187,6 @@ ActivityStreams.prototype = {
     /* note: this will execute for each of the 3 notifications that occur
      * when adding a visit: frecency:-1, frecency: real frecency, title */
     if (!this._populatingCache.places) {
-      this._invalidatePlacesCache();
       this._asyncBuildPlacesCache();
     }
 
@@ -300,13 +299,14 @@ ActivityStreams.prototype = {
     if (simplePrefs.prefs["query.cache"]) {
       if (!this._populatingCache.places) {
         this._populatingCache.places = true;
+        let opt = {replace: true};
         yield Promise.all([
-            this._memoized.getTopFrecentSites(),
-            this._memoized.getRecentBookmarks(),
-            this._memoized.getRecentLinks(),
-            this._memoized.getHighlightsLinks(),
-            this._memoized.getHistorySize(),
-            this._memoized.getBookmarksSize(),
+            this._memoized.getTopFrecentSites(opt),
+            this._memoized.getRecentBookmarks(opt),
+            this._memoized.getRecentLinks(opt),
+            this._memoized.getHighlightsLinks(opt),
+            this._memoized.getHistorySize(opt),
+            this._memoized.getBookmarksSize(opt),
         ]);
         this._populatingCache.places = false;
         Services.obs.notifyObservers(null, "activity-streams-places-cache-complete", null);
@@ -360,20 +360,6 @@ ActivityStreams.prototype = {
     }
   },
 
-  /**
-   * Invalidates the places pageload cache
-   */
-  _invalidatePlacesCache() {
-    this._memoizer.invalidateMemos([
-        "getTopFrecentSites",
-        "getRecentBookmarks",
-        "getRecentLinks",
-        "getHighlightsLinks",
-        "getHistorySize",
-        "getBookmarksSize",
-    ]);
-  },
-
   /**
    * Sets up communications with the pages and manages the lifecycle of workers
    */

lib/Memoizer.js

@@ -35,10 +35,21 @@ Memoizer.prototype = {
    */
   memoize(key, func) {
     return (...args) => {
+
+      // figure out if we need to replace the cache for this query
+      let replace = false;
+      args = args.filter(arg => {
+        if (typeof arg === "object" && "replace" in arg) {
+          replace = arg.replace;
+          return false;
+        }
+        return true;
+      });
+
       // allow object params to be passed, as is expected of query functions
       let repr = this._makeRepr(args);
 
-      if (this._cacheEnabled && this.hasRepr(key, repr)) {
+      if (this._cacheEnabled && !replace && this.hasRepr(key, repr)) {
         Services.obs.notifyObservers(null, `${key}-cache`, "hit");
         return new Promise(resolve => resolve(this.getData(key, repr)));
       } else {

test/test-Memoizer.js

@@ -29,6 +29,48 @@ exports.test_memoizer = function*(assert) {
   assert.equal(result, 2, "cached result is obtained");
 };
 
+exports.test_memoizer_replace_opt = function*(assert) {
+  let count = 0;
+  let testFunc = () => {
+    return ++count;
+  };
+  let func = gMemoizer.memoize("testKey", testFunc);
+  let result;
+
+  result = yield func();
+  assert.equal(result, 1, "test function executes");
+
+  result = yield func();
+  assert.equal(result, 1, "cached result is obtained");
+
+  result = yield func({replace: true});
+  assert.equal(result, 2, "test function executes");
+
+  result = yield func();
+  assert.equal(result, 2, "cached result is obtained");
+};
+
+exports.test_memoizer_replace_opt_sub_key = function*(assert) {
+  let count = 0;
+  let testFunc = () => {
+    return ++count;
+  };
+  let func = gMemoizer.memoize("testKey", testFunc);
+  let result;
+
+  result = yield func("sub-key");
+  assert.equal(result, 1, "test function executes");
+
+  result = yield func("sub-key");
+  assert.equal(result, 1, "cached result is obtained");
+
+  result = yield func("sub-key", {replace: true});
+  assert.equal(result, 2, "test function executes");
+
+  result = yield func("sub-key");
+  assert.equal(result, 2, "cached result is obtained");
+};
+
 exports.test_memoizer_prefs = function*(assert) {
   simplePrefs.prefs["query.cache"] = false;
   let count = 0;