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Issue 29338442: Issue 3815 - Fix TabAllocator. Now it returns tab with initialized outerWindowID (Closed)
Patch Set: eliminate race conditions Created April 11, 2016, 3:06 p.m.
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1 /* 1 /*
2 * This Source Code is subject to the terms of the Mozilla Public License 2 * This Source Code is subject to the terms of the Mozilla Public License
3 * version 2.0 (the "License"). You can obtain a copy of the License at 3 * version 2.0 (the "License"). You can obtain a copy of the License at
4 * http://mozilla.org/MPL/2.0/. 4 * http://mozilla.org/MPL/2.0/.
5 */ 5 */
6 6
7 /** 7 /**
8 * @module crawler 8 * @module crawler
9 */ 9 */
10 10
11 Cu.import("resource://gre/modules/Services.jsm"); 11 Cu.import("resource://gre/modules/Services.jsm");
12 Cu.import("resource://gre/modules/Task.jsm"); 12 Cu.import("resource://gre/modules/Task.jsm");
13 Cu.import("resource://gre/modules/Promise.jsm"); 13 Cu.import("resource://gre/modules/Promise.jsm");
14 14
15 function abprequire(module) 15 function abprequire(module)
16 { 16 {
17 let result = {}; 17 let result = {};
18 result.wrappedJSObject = result; 18 result.wrappedJSObject = result;
19 Services.obs.notifyObservers(result, "adblockplus-require", module); 19 Services.obs.notifyObservers(result, "adblockplus-require", module);
20 return result.exports; 20 return result.exports;
21 } 21 }
22 22
23 let {RequestNotifier} = abprequire("requestNotifier"); 23 let {RequestNotifier} = abprequire("requestNotifier");
24 let {FilterNotifier} = abprequire("filterNotifier"); 24 let {FilterNotifier} = abprequire("filterNotifier");
25 let {FilterStorage} = abprequire("filterStorage"); 25 let {FilterStorage} = abprequire("filterStorage");
26 26
27 /** 27 /**
28 * Creates a pool of tabs and allocates them to tasks on request. 28 * Allocates tabs on request but not more than maxtabs at the same time.
29 * 29 *
30 * @param {tabbrowser} browser 30 * @param {tabbrowser} browser
31 * The tabbed browser where tabs should be created 31 * The tabbed browser where tabs should be created
32 * @param {int} maxtabs 32 * @param {int} maxtabs
33 * The maximum number of tabs to be allocated 33 * The maximum number of tabs to be allocated
34 * @constructor 34 * @constructor
35 */ 35 */
36 function TabAllocator(browser, maxtabs) 36 function TabAllocator(browser, maxtabs)
37 { 37 {
38 browser.removeAllTabsBut(browser.tabs[0]) 38 this._browser = browser;
39 39 this._tabs = 0;
40 this._tabs = []; 40 this._maxtabs = maxtabs;
41 for (let i = 0; i < maxtabs; i++) 41 // The queue containing resolve functions of promises waiting for a tab.
42 this._tabs.push(browser.addTab("about:blank")); 42 this._resolvers = [];
43 43 // Keep at least one tab alive to prevent browser from closing itself.
44 browser.removeTab(browser.tabs[0]); 44 let tabToRemove = this._browser.tabs[0];
45 45 this._browser.removeAllTabsBut(tabToRemove);
46 this._deferred = []; 46 // this._tab is a keep alive tab
47 this._tab = this._createTab().then(tab =>
48 {
49 // Starting from Firefox 48 (nightly) the sequence of calls addTab and
50 // removeTab can cause a closing of the browser because a new tab is still
51 // not here. Because of that we need to remove the previous tab only after
52 // the new tab is ready.
53 this._browser.removeTab(tabToRemove);
54 return tab;
55 });
Wladimir Palant 2016/09/14 15:00:13 There is little point pre-allocating a tab, you ca
sergei 2016/09/15 15:33:27 Done.
47 } 56 }
48 TabAllocator.prototype = { 57 TabAllocator.prototype = {
49 /** 58 /**
50 * Returns a promise that will resolve into a tab once a tab can be allocated. 59 * Creates a blank tab in this._browser.
60 *
61 * @return {Promise.<tab>} promise which resolves once the tab is fully initia lized.
62 */
63 _createTab: function()
64 {
65 this._tabs++;
66 let tab = this._browser.addTab("about:blank");
67 if (tab.linkedBrowser.outerWindowID)
68 return Promise.resolve(tab);
69 return new Promise((resolve, reject) =>
70 {
71 let onBrowserInit = (msg) =>
72 {
73 // https://bugzilla.mozilla.org/show_bug.cgi?id=1256602#c1
Wladimir Palant 2016/09/14 15:00:13 Please don't use URL-only comments, it should be o
sergei 2016/09/15 15:33:27 Done.
74 tab.linkedBrowser.messageManager.removeMessageListener("Browser:Init", o nBrowserInit);
75 resolve(tab);
76 };
77 tab.linkedBrowser.messageManager.addMessageListener("Browser:Init", onBrow serInit);
78 });
79 },
80
81 /**
82 * Returns a promise that will resolve into a tab once a tab is allocated.
51 * The tab cannot be used by other tasks until releaseTab() is called. 83 * The tab cannot be used by other tasks until releaseTab() is called.
52 * 84 *
53 * @result {Promise} 85 * @result {Promise.<tab>}
54 */ 86 */
55 getTab: function() 87 getTab: function()
56 { 88 {
57 if (this._tabs.length) 89 if (this._tab)
58 return this._tabs.shift();
59 else
60 { 90 {
61 let deferred = Promise.defer(); 91 let tab = this._tab;
62 this._deferred.push(deferred); 92 delete this._tab;
63 return deferred.promise; 93 return tab;
64 } 94 }
95 if (this._tabs < this._maxtabs)
96 return this._createTab();
97 return new Promise((resolve, reject) => this._resolvers.push(resolve));
65 }, 98 },
66 99
67 /** 100 /**
68 * Adds a tab back to the pool so that it can be used by other tasks. 101 * Adds a tab back to the pool so that it can be used by other tasks.
69 * 102 *
70 * @param {tab} tab 103 * @param {tab} tab
71 */ 104 */
72 releaseTab: function(tab) 105 releaseTab: function(tab)
73 { 106 {
74 let browser = tab.parentNode.tabbrowser; 107 // If we are about to close last tab don't close it immediately rather
75 browser.removeTab(tab); 108 // allocate a new blank tab and close the current one afterwards.
76 tab = browser.addTab("about:blank"); 109 if (this._tabs == 1)
110 {
111 this._tab = this._createTab().then((resultTab) =>
112 {
113 this.releaseTab(tab);
114 return resultTab;
115 });
116 return;
117 }
77 118
78 if (this._deferred.length) 119 this._browser.removeTab(tab);
79 this._deferred.shift().resolve(tab); 120 this._tabs--;
80 else 121 if (this._resolvers.length)
81 this._tabs.push(tab); 122 {
82 } 123 if (this._tab)
124 {
125 this._resolvers.shift()(this._tab);
126 delete this._tab;
127 }
128 else if (this._tabs < this._maxtabs)
129 {
130 this._resolvers.shift()(this._createTab());
131 }
132 }
133 },
83 }; 134 };
84 135
85 /** 136 /**
86 * Observes page loads in a particular tabbed browser. 137 * Observes page loads in a particular tabbed browser.
87 * 138 *
88 * @param {tabbrowser} browser 139 * @param {tabbrowser} browser
89 * The tabbed browser to be observed 140 * The tabbed browser to be observed
90 * @param {int} timeout 141 * @param {int} timeout
91 * Load timeout in milliseconds 142 * Load timeout in milliseconds
92 * @constructor 143 * @constructor
(...skipping 131 matching lines...) Expand 10 before | Expand all | Expand 10 after
224 resolve(); 275 resolve();
225 } 276 }
226 }; 277 };
227 FilterNotifier.addListener(onFiltersLoaded); 278 FilterNotifier.addListener(onFiltersLoaded);
228 }).then(() => crawl_urls(window, urls, timeout, maxtabs, targetURL, onDone)) 279 }).then(() => crawl_urls(window, urls, timeout, maxtabs, targetURL, onDone))
229 .catch(reportException); 280 .catch(reportException);
230 } 281 }
231 exports.run = run; 282 exports.run = run;
232 283
233 /** 284 /**
234 * Spawns a {Task} task to crawl each url from `urls` argument and calls 285 * Spawns a {Task} task to crawl each url from urls argument and calls
235 * `onDone` when all tasks are finished. 286 * onDone when all tasks are finished.
236 * @param {Window} window 287 * @param {Window} window
237 * The browser window we're operating in 288 * The browser window we're operating in
238 * @param {String[]} urls 289 * @param {String[]} urls
239 * URLs to be crawled 290 * URLs to be crawled
240 * @param {int} timeout 291 * @param {int} timeout
241 * Load timeout in milliseconds 292 * Load timeout in milliseconds
242 * @param {int} maxtabs 293 * @param {int} maxtabs
243 * Maximum number of tabs to be opened 294 * Maximum number of tabs to be opened
244 * @param {String} targetURL 295 * @param {String} targetURL
245 * URL that should receive the results 296 * URL that should receive the results
(...skipping 110 matching lines...) Expand 10 before | Expand all | Expand 10 after
356 407
357 function reportException(e) 408 function reportException(e)
358 { 409 {
359 let stack = ""; 410 let stack = "";
360 if (e && typeof e == "object" && "stack" in e) 411 if (e && typeof e == "object" && "stack" in e)
361 stack = e.stack + "\n"; 412 stack = e.stack + "\n";
362 413
363 Cu.reportError(e); 414 Cu.reportError(e);
364 dump(e + "\n" + stack + "\n"); 415 dump(e + "\n" + stack + "\n");
365 } 416 }
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