fix for bug #381216:

prevent bookmarks dataloss when a user goes from Firefox 2, Firefox 3 beta, Firefox 2 and then back to Firefox 3.

r=dietrich, a=schrep/beltzner

browser/app/profile/firefox.js

@@ -293,6 +293,10 @@ pref("browser.tabs.selectOwnerOnClose", true);
 pref("browser.bookmarks.sort.direction", "descending");
 pref("browser.bookmarks.sort.resource", "rdf:http://home.netscape.com/NC-rdf#Name");
 
+// By default, do not overwrite bookmarks.html in the profile directory
+// See bug #381216 for details
+pref("browser.bookmarks.overwrite",               false);
+
 // Scripts & Windows prefs
 pref("dom.disable_open_during_load",              true);
 #ifdef DEBUG

browser/components/nsBrowserGlue.js

@@ -359,17 +359,20 @@ BrowserGlue.prototype = {
         prefBranch.setBoolPref("browser.places.importBookmarksHTML", false);
       }
 
-      // backup pre-places bookmarks.html
-      // XXXtodo remove this before betas, after import/export is solid
-      var profDir = dirService.get("ProfD", Ci.nsILocalFile);
-      var bookmarksBackup = profDir.clone();
-      bookmarksBackup.append("bookmarks.preplaces.html");
-      if (!bookmarksBackup.exists()) {
-        // save old bookmarks.html file as bookmarks.preplaces.html
-        try {
-          bookmarksFile.copyTo(profDir, "bookmarks.preplaces.html");
-        } catch(ex) {
-          dump("nsBrowserGlue::_initPlaces(): copy of bookmarks.html to bookmarks.preplaces.html failed: " + ex + "\n");
+      // only back up pre-places bookmarks.html if we plan on overwriting it
+      if (prefBranch.getBoolPref("browser.bookmarks.overwrite")) {
+        // backup pre-places bookmarks.html
+        // XXXtodo remove this before betas, after import/export is solid
+        var profDir = dirService.get("ProfD", Ci.nsILocalFile);
+        var bookmarksBackup = profDir.clone();
+        bookmarksBackup.append("bookmarks.preplaces.html");
+        if (!bookmarksBackup.exists()) {
+          // save old bookmarks.html file as bookmarks.preplaces.html
+          try {
+            bookmarksFile.copyTo(profDir, "bookmarks.preplaces.html");
+          } catch(ex) {
+            dump("nsBrowserGlue::_initPlaces(): copy of bookmarks.html to bookmarks.preplaces.html failed: " + ex + "\n");
+          }
         }
       }
     }

browser/components/places/src/nsPlacesImportExportService.cpp

@@ -2475,17 +2475,33 @@ nsPlacesImportExportService::ExportHTMLToFile(nsILocalFile* aBookmarksFile)
   return rv;
 }
 
+#define BROWSER_BOOKMARKS_OVERWRITE_PREF    "browser.bookmarks.overwrite"
+#define BROWSER_BOOKMARKS_MAX_BACKUPS_PREF  "browser.bookmarks.max_backups"
+#define POSTPLACES_BOOKMARKS_FILE           "bookmarks.postplaces.html"
+
 NS_IMETHODIMP
 nsPlacesImportExportService::BackupBookmarksFile()
 {
   nsresult rv = EnsureServiceState();
   NS_ENSURE_SUCCESS(rv, rv);
 
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+
   // get bookmarks file
   nsCOMPtr<nsIFile> bookmarksFileDir;
   rv = NS_GetSpecialDirectory(NS_APP_BOOKMARKS_50_FILE,
                               getter_AddRefs(bookmarksFileDir));
 
+  PRBool overwriteBookmarks;
+  rv = prefs->GetBoolPref(BROWSER_BOOKMARKS_OVERWRITE_PREF, &overwriteBookmarks);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!overwriteBookmarks) {
+    rv = bookmarksFileDir->SetLeafName(NS_LITERAL_STRING(POSTPLACES_BOOKMARKS_FILE));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
   NS_ENSURE_SUCCESS(rv, rv);
   nsCOMPtr<nsILocalFile> bookmarksFile(do_QueryInterface(bookmarksFileDir));
 
@@ -2503,14 +2519,8 @@ nsPlacesImportExportService::BackupBookmarksFile()
   NS_ENSURE_SUCCESS(rv, rv);
 
   // archive if needed
-  nsCOMPtr<nsIPrefService> prefServ(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
-  NS_ENSURE_SUCCESS(rv, rv);
-  nsCOMPtr<nsIPrefBranch> bookmarksPrefs;
-  rv = prefServ->GetBranch("browser.bookmarks.", getter_AddRefs(bookmarksPrefs));
-  NS_ENSURE_SUCCESS(rv, rv);
-
   PRInt32 numberOfBackups;
-  rv = bookmarksPrefs->GetIntPref("max_backups", &numberOfBackups);
+  rv = prefs->GetIntPref(BROWSER_BOOKMARKS_MAX_BACKUPS_PREF, &numberOfBackups);
   if (NS_FAILED(rv))
     numberOfBackups = 5;
 
@@ -2633,6 +2643,18 @@ nsPlacesImportExportService::ArchiveBookmarksFile(PRInt32 numberOfBackups,
   rv = NS_GetSpecialDirectory(NS_APP_BOOKMARKS_50_FILE,
                               getter_AddRefs(bookmarksFile));
   NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  PRBool overwriteBookmarks;
+  rv = prefs->GetBoolPref(BROWSER_BOOKMARKS_OVERWRITE_PREF, &overwriteBookmarks);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!overwriteBookmarks) {
+    rv = bookmarksFile->SetLeafName(NS_LITERAL_STRING(POSTPLACES_BOOKMARKS_FILE));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
   
   rv = bookmarksFile->CopyTo(bookmarksBackupDir, backupFilenameString);
   // at least dump something out in case this fails in a debug build