michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0: * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0: * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["SessionHistory"];
michael@0: 
michael@0: const Cu = Components.utils;
michael@0: const Cc = Components.classes;
michael@0: const Ci = Components.interfaces;
michael@0: 
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: 
michael@0: XPCOMUtils.defineLazyModuleGetter(this, "Utils",
michael@0:   "resource:///modules/sessionstore/Utils.jsm");
michael@0: 
michael@0: function debug(msg) {
michael@0:   Services.console.logStringMessage("SessionHistory: " + msg);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * The external API exported by this module.
michael@0:  */
michael@0: this.SessionHistory = Object.freeze({
michael@0:   isEmpty: function (docShell) {
michael@0:     return SessionHistoryInternal.isEmpty(docShell);
michael@0:   },
michael@0: 
michael@0:   collect: function (docShell) {
michael@0:     return SessionHistoryInternal.collect(docShell);
michael@0:   },
michael@0: 
michael@0:   restore: function (docShell, tabData) {
michael@0:     SessionHistoryInternal.restore(docShell, tabData);
michael@0:   }
michael@0: });
michael@0: 
michael@0: /**
michael@0:  * The internal API for the SessionHistory module.
michael@0:  */
michael@0: let SessionHistoryInternal = {
michael@0:   /**
michael@0:    * Returns whether the given docShell's session history is empty.
michael@0:    *
michael@0:    * @param docShell
michael@0:    *        The docShell that owns the session history.
michael@0:    */
michael@0:   isEmpty: function (docShell) {
michael@0:     let webNavigation = docShell.QueryInterface(Ci.nsIWebNavigation);
michael@0:     let history = webNavigation.sessionHistory;
michael@0:     if (!webNavigation.currentURI) {
michael@0:       return true;
michael@0:     }
michael@0:     let uri = webNavigation.currentURI.spec;
michael@0:     return uri == "about:blank" && history.count == 0;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Collects session history data for a given docShell.
michael@0:    *
michael@0:    * @param docShell
michael@0:    *        The docShell that owns the session history.
michael@0:    */
michael@0:   collect: function (docShell) {
michael@0:     let data = {entries: []};
michael@0:     let isPinned = docShell.isAppTab;
michael@0:     let webNavigation = docShell.QueryInterface(Ci.nsIWebNavigation);
michael@0:     let history = webNavigation.sessionHistory;
michael@0: 
michael@0:     if (history && history.count > 0) {
michael@0:       let oldest;
michael@0:       let maxSerializeBack =
michael@0:         Services.prefs.getIntPref("browser.sessionstore.max_serialize_back");
michael@0:       if (maxSerializeBack >= 0) {
michael@0:         oldest = Math.max(0, history.index - maxSerializeBack);
michael@0:       } else { // History.getEntryAtIndex(0, ...) is the oldest.
michael@0:         oldest = 0;
michael@0:       }
michael@0: 
michael@0:       let newest;
michael@0:       let maxSerializeFwd =
michael@0:         Services.prefs.getIntPref("browser.sessionstore.max_serialize_forward");
michael@0:       if (maxSerializeFwd >= 0) {
michael@0:         newest = Math.min(history.count - 1, history.index + maxSerializeFwd);
michael@0:       } else { // History.getEntryAtIndex(history.count - 1, ...) is the newest.
michael@0:         newest = history.count - 1;
michael@0:       }
michael@0: 
michael@0:       try {
michael@0:         for (let i = oldest; i <= newest; i++) {
michael@0:           let shEntry = history.getEntryAtIndex(i, false);
michael@0:           let entry = this.serializeEntry(shEntry, isPinned);
michael@0:           data.entries.push(entry);
michael@0:         }
michael@0:       } catch (ex) {
michael@0:         // In some cases, getEntryAtIndex will throw. This seems to be due to
michael@0:         // history.count being higher than it should be. By doing this in a
michael@0:         // try-catch, we'll update history to where it breaks, print an error
michael@0:         // message, and still save sessionstore.js.
michael@0:         debug("SessionStore failed gathering complete history " +
michael@0:               "for the focused window/tab. See bug 669196.");
michael@0:       }
michael@0: 
michael@0:       // Set the one-based index of the currently active tab,
michael@0:       // ensuring it isn't out of bounds if an exception was thrown above.
michael@0:       data.index = Math.min(history.index - oldest + 1, data.entries.length);
michael@0:     }
michael@0: 
michael@0:     // If either the session history isn't available yet or doesn't have any
michael@0:     // valid entries, make sure we at least include the current page.
michael@0:     if (data.entries.length == 0) {
michael@0:       let uri = webNavigation.currentURI.spec;
michael@0:       let body = webNavigation.document.body;
michael@0:       // We landed here because the history is inaccessible or there are no
michael@0:       // history entries. In that case we should at least record the docShell's
michael@0:       // current URL as a single history entry. If the URL is not about:blank
michael@0:       // or it's a blank tab that was modified (like a custom newtab page),
michael@0:       // record it. For about:blank we explicitly want an empty array without
michael@0:       // an 'index' property to denote that there are no history entries.
michael@0:       if (uri != "about:blank" || (body && body.hasChildNodes())) {
michael@0:         data.entries.push({ url: uri });
michael@0:         data.index = 1;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return data;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Determines whether a given session history entry has been added dynamically.
michael@0:    *
michael@0:    * @param shEntry
michael@0:    *        The session history entry.
michael@0:    * @return bool
michael@0:    */
michael@0:   isDynamic: function (shEntry) {
michael@0:     // shEntry.isDynamicallyAdded() is true for dynamically added
michael@0:     // <iframe> and <frameset>, but also for <html> (the root of the
michael@0:     // document) so we use shEntry.parent to ensure that we're not looking
michael@0:     // at the root of the document
michael@0:     return shEntry.parent && shEntry.isDynamicallyAdded();
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Get an object that is a serialized representation of a History entry.
michael@0:    *
michael@0:    * @param shEntry
michael@0:    *        nsISHEntry instance
michael@0:    * @param isPinned
michael@0:    *        The tab is pinned and should be treated differently for privacy.
michael@0:    * @return object
michael@0:    */
michael@0:   serializeEntry: function (shEntry, isPinned) {
michael@0:     let entry = { url: shEntry.URI.spec };
michael@0: 
michael@0:     // Save some bytes and don't include the title property
michael@0:     // if that's identical to the current entry's URL.
michael@0:     if (shEntry.title && shEntry.title != entry.url) {
michael@0:       entry.title = shEntry.title;
michael@0:     }
michael@0:     if (shEntry.isSubFrame) {
michael@0:       entry.subframe = true;
michael@0:     }
michael@0: 
michael@0:     let cacheKey = shEntry.cacheKey;
michael@0:     if (cacheKey && cacheKey instanceof Ci.nsISupportsPRUint32 &&
michael@0:         cacheKey.data != 0) {
michael@0:       // XXXbz would be better to have cache keys implement
michael@0:       // nsISerializable or something.
michael@0:       entry.cacheKey = cacheKey.data;
michael@0:     }
michael@0:     entry.ID = shEntry.ID;
michael@0:     entry.docshellID = shEntry.docshellID;
michael@0: 
michael@0:     // We will include the property only if it's truthy to save a couple of
michael@0:     // bytes when the resulting object is stringified and saved to disk.
michael@0:     if (shEntry.referrerURI)
michael@0:       entry.referrer = shEntry.referrerURI.spec;
michael@0: 
michael@0:     if (shEntry.srcdocData)
michael@0:       entry.srcdocData = shEntry.srcdocData;
michael@0: 
michael@0:     if (shEntry.isSrcdocEntry)
michael@0:       entry.isSrcdocEntry = shEntry.isSrcdocEntry;
michael@0: 
michael@0:     if (shEntry.baseURI)
michael@0:       entry.baseURI = shEntry.baseURI.spec;
michael@0: 
michael@0:     if (shEntry.contentType)
michael@0:       entry.contentType = shEntry.contentType;
michael@0: 
michael@0:     let x = {}, y = {};
michael@0:     shEntry.getScrollPosition(x, y);
michael@0:     if (x.value != 0 || y.value != 0)
michael@0:       entry.scroll = x.value + "," + y.value;
michael@0: 
michael@0:     // Collect owner data for the current history entry.
michael@0:     try {
michael@0:       let owner = this.serializeOwner(shEntry);
michael@0:       if (owner) {
michael@0:         entry.owner_b64 = owner;
michael@0:       }
michael@0:     } catch (ex) {
michael@0:       // Not catching anything specific here, just possible errors
michael@0:       // from writeCompoundObject() and the like.
michael@0:       debug("Failed serializing owner data: " + ex);
michael@0:     }
michael@0: 
michael@0:     entry.docIdentifier = shEntry.BFCacheEntry.ID;
michael@0: 
michael@0:     if (shEntry.stateData != null) {
michael@0:       entry.structuredCloneState = shEntry.stateData.getDataAsBase64();
michael@0:       entry.structuredCloneVersion = shEntry.stateData.formatVersion;
michael@0:     }
michael@0: 
michael@0:     if (!(shEntry instanceof Ci.nsISHContainer)) {
michael@0:       return entry;
michael@0:     }
michael@0: 
michael@0:     if (shEntry.childCount > 0) {
michael@0:       let children = [];
michael@0:       for (let i = 0; i < shEntry.childCount; i++) {
michael@0:         let child = shEntry.GetChildAt(i);
michael@0: 
michael@0:         if (child && !this.isDynamic(child)) {
michael@0:           // Don't try to restore framesets containing wyciwyg URLs.
michael@0:           // (cf. bug 424689 and bug 450595)
michael@0:           if (child.URI.schemeIs("wyciwyg")) {
michael@0:             children.length = 0;
michael@0:             break;
michael@0:           }
michael@0: 
michael@0:           children.push(this.serializeEntry(child, isPinned));
michael@0:         }
michael@0:       }
michael@0: 
michael@0:       if (children.length) {
michael@0:         entry.children = children;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return entry;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Serialize owner data contained in the given session history entry.
michael@0:    *
michael@0:    * @param shEntry
michael@0:    *        The session history entry.
michael@0:    * @return The base64 encoded owner data.
michael@0:    */
michael@0:   serializeOwner: function (shEntry) {
michael@0:     if (!shEntry.owner) {
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     let binaryStream = Cc["@mozilla.org/binaryoutputstream;1"].
michael@0:                        createInstance(Ci.nsIObjectOutputStream);
michael@0:     let pipe = Cc["@mozilla.org/pipe;1"].createInstance(Ci.nsIPipe);
michael@0:     pipe.init(false, false, 0, 0xffffffff, null);
michael@0:     binaryStream.setOutputStream(pipe.outputStream);
michael@0:     binaryStream.writeCompoundObject(shEntry.owner, Ci.nsISupports, true);
michael@0:     binaryStream.close();
michael@0: 
michael@0:     // Now we want to read the data from the pipe's input end and encode it.
michael@0:     let scriptableStream = Cc["@mozilla.org/binaryinputstream;1"].
michael@0:                            createInstance(Ci.nsIBinaryInputStream);
michael@0:     scriptableStream.setInputStream(pipe.inputStream);
michael@0:     let ownerBytes =
michael@0:       scriptableStream.readByteArray(scriptableStream.available());
michael@0: 
michael@0:     // We can stop doing base64 encoding once our serialization into JSON
michael@0:     // is guaranteed to handle all chars in strings, including embedded
michael@0:     // nulls.
michael@0:     return btoa(String.fromCharCode.apply(null, ownerBytes));
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Restores session history data for a given docShell.
michael@0:    *
michael@0:    * @param docShell
michael@0:    *        The docShell that owns the session history.
michael@0:    * @param tabData
michael@0:    *        The tabdata including all history entries.
michael@0:    */
michael@0:   restore: function (docShell, tabData) {
michael@0:     let webNavigation = docShell.QueryInterface(Ci.nsIWebNavigation);
michael@0:     let history = webNavigation.sessionHistory;
michael@0: 
michael@0:     if (history.count > 0) {
michael@0:       history.PurgeHistory(history.count);
michael@0:     }
michael@0:     history.QueryInterface(Ci.nsISHistoryInternal);
michael@0: 
michael@0:     let idMap = { used: {} };
michael@0:     let docIdentMap = {};
michael@0:     for (let i = 0; i < tabData.entries.length; i++) {
michael@0:       //XXXzpao Wallpaper patch for bug 514751
michael@0:       if (!tabData.entries[i].url)
michael@0:         continue;
michael@0:       history.addEntry(this.deserializeEntry(tabData.entries[i],
michael@0:                                              idMap, docIdentMap), true);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Expands serialized history data into a session-history-entry instance.
michael@0:    *
michael@0:    * @param entry
michael@0:    *        Object containing serialized history data for a URL
michael@0:    * @param idMap
michael@0:    *        Hash for ensuring unique frame IDs
michael@0:    * @param docIdentMap
michael@0:    *        Hash to ensure reuse of BFCache entries
michael@0:    * @returns nsISHEntry
michael@0:    */
michael@0:   deserializeEntry: function (entry, idMap, docIdentMap) {
michael@0: 
michael@0:     var shEntry = Cc["@mozilla.org/browser/session-history-entry;1"].
michael@0:                   createInstance(Ci.nsISHEntry);
michael@0: 
michael@0:     shEntry.setURI(Utils.makeURI(entry.url));
michael@0:     shEntry.setTitle(entry.title || entry.url);
michael@0:     if (entry.subframe)
michael@0:       shEntry.setIsSubFrame(entry.subframe || false);
michael@0:     shEntry.loadType = Ci.nsIDocShellLoadInfo.loadHistory;
michael@0:     if (entry.contentType)
michael@0:       shEntry.contentType = entry.contentType;
michael@0:     if (entry.referrer)
michael@0:       shEntry.referrerURI = Utils.makeURI(entry.referrer);
michael@0:     if (entry.isSrcdocEntry)
michael@0:       shEntry.srcdocData = entry.srcdocData;
michael@0:     if (entry.baseURI)
michael@0:       shEntry.baseURI = Utils.makeURI(entry.baseURI);
michael@0: 
michael@0:     if (entry.cacheKey) {
michael@0:       var cacheKey = Cc["@mozilla.org/supports-PRUint32;1"].
michael@0:                      createInstance(Ci.nsISupportsPRUint32);
michael@0:       cacheKey.data = entry.cacheKey;
michael@0:       shEntry.cacheKey = cacheKey;
michael@0:     }
michael@0: 
michael@0:     if (entry.ID) {
michael@0:       // get a new unique ID for this frame (since the one from the last
michael@0:       // start might already be in use)
michael@0:       var id = idMap[entry.ID] || 0;
michael@0:       if (!id) {
michael@0:         for (id = Date.now(); id in idMap.used; id++);
michael@0:         idMap[entry.ID] = id;
michael@0:         idMap.used[id] = true;
michael@0:       }
michael@0:       shEntry.ID = id;
michael@0:     }
michael@0: 
michael@0:     if (entry.docshellID)
michael@0:       shEntry.docshellID = entry.docshellID;
michael@0: 
michael@0:     if (entry.structuredCloneState && entry.structuredCloneVersion) {
michael@0:       shEntry.stateData =
michael@0:         Cc["@mozilla.org/docshell/structured-clone-container;1"].
michael@0:         createInstance(Ci.nsIStructuredCloneContainer);
michael@0: 
michael@0:       shEntry.stateData.initFromBase64(entry.structuredCloneState,
michael@0:                                        entry.structuredCloneVersion);
michael@0:     }
michael@0: 
michael@0:     if (entry.scroll) {
michael@0:       var scrollPos = (entry.scroll || "0,0").split(",");
michael@0:       scrollPos = [parseInt(scrollPos[0]) || 0, parseInt(scrollPos[1]) || 0];
michael@0:       shEntry.setScrollPosition(scrollPos[0], scrollPos[1]);
michael@0:     }
michael@0: 
michael@0:     let childDocIdents = {};
michael@0:     if (entry.docIdentifier) {
michael@0:       // If we have a serialized document identifier, try to find an SHEntry
michael@0:       // which matches that doc identifier and adopt that SHEntry's
michael@0:       // BFCacheEntry.  If we don't find a match, insert shEntry as the match
michael@0:       // for the document identifier.
michael@0:       let matchingEntry = docIdentMap[entry.docIdentifier];
michael@0:       if (!matchingEntry) {
michael@0:         matchingEntry = {shEntry: shEntry, childDocIdents: childDocIdents};
michael@0:         docIdentMap[entry.docIdentifier] = matchingEntry;
michael@0:       }
michael@0:       else {
michael@0:         shEntry.adoptBFCacheEntry(matchingEntry.shEntry);
michael@0:         childDocIdents = matchingEntry.childDocIdents;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     if (entry.owner_b64) {
michael@0:       var ownerInput = Cc["@mozilla.org/io/string-input-stream;1"].
michael@0:                        createInstance(Ci.nsIStringInputStream);
michael@0:       var binaryData = atob(entry.owner_b64);
michael@0:       ownerInput.setData(binaryData, binaryData.length);
michael@0:       var binaryStream = Cc["@mozilla.org/binaryinputstream;1"].
michael@0:                          createInstance(Ci.nsIObjectInputStream);
michael@0:       binaryStream.setInputStream(ownerInput);
michael@0:       try { // Catch possible deserialization exceptions
michael@0:         shEntry.owner = binaryStream.readObject(true);
michael@0:       } catch (ex) { debug(ex); }
michael@0:     }
michael@0: 
michael@0:     if (entry.children && shEntry instanceof Ci.nsISHContainer) {
michael@0:       for (var i = 0; i < entry.children.length; i++) {
michael@0:         //XXXzpao Wallpaper patch for bug 514751
michael@0:         if (!entry.children[i].url)
michael@0:           continue;
michael@0: 
michael@0:         // We're getting sessionrestore.js files with a cycle in the
michael@0:         // doc-identifier graph, likely due to bug 698656.  (That is, we have
michael@0:         // an entry where doc identifier A is an ancestor of doc identifier B,
michael@0:         // and another entry where doc identifier B is an ancestor of A.)
michael@0:         //
michael@0:         // If we were to respect these doc identifiers, we'd create a cycle in
michael@0:         // the SHEntries themselves, which causes the docshell to loop forever
michael@0:         // when it looks for the root SHEntry.
michael@0:         //
michael@0:         // So as a hack to fix this, we restrict the scope of a doc identifier
michael@0:         // to be a node's siblings and cousins, and pass childDocIdents, not
michael@0:         // aDocIdents, to _deserializeHistoryEntry.  That is, we say that two
michael@0:         // SHEntries with the same doc identifier have the same document iff
michael@0:         // they have the same parent or their parents have the same document.
michael@0: 
michael@0:         shEntry.AddChild(this.deserializeEntry(entry.children[i], idMap,
michael@0:                                                childDocIdents), i);
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return shEntry;
michael@0:   },
michael@0: 
michael@0: };