Bug 230870 - Cross-Session resumable downloads (resume after quitting firefox). r=sdwilsh, a=mconnor

toolkit/components/downloads/src/nsDownloadManager.cpp

@@ -24,6 +24,7 @@
  *   Ben Goodger <ben@netscape.com> (Original Author)
  *   Shawn Wilsher <me@shawnwilsher.com>
  *   Srirang G Doddihal <brahmana@doddihal.com>
+ *   Edward Lee <edward.lee@engineering.uiuc.edu>
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
@@ -129,16 +130,21 @@ nsDownloadManager::~nsDownloadManager()
 }
 
 nsresult
-nsDownloadManager::CancelAllDownloads()
+nsDownloadManager::RemoveAllDownloads()
 {
   nsresult rv = NS_OK;
   for (PRInt32 i = mCurrentDownloads.Count() - 1; i >= 0; --i) {
     nsRefPtr<nsDownload> dl = mCurrentDownloads[0];
 
-    nsresult result = CancelDownload(dl->mID);
-    // We want to try the rest of them because they should be canceled if they
-    // can be canceled.
-    if (NS_FAILED(result)) rv = result;
+    nsresult result;
+    if (dl->IsRealPaused())
+      result = mCurrentDownloads.RemoveObject(dl);
+    else
+      result = CancelDownload(dl->mID);
+
+    // Track the failure, but don't miss out on other downloads
+    if (NS_FAILED(result))
+      rv = result;
   }
 
   return rv;
@@ -644,6 +650,33 @@ nsDownloadManager::RestoreDatabaseState()
   return NS_OK;
 }
 
+nsresult
+nsDownloadManager::RestoreActiveDownloads()
+{
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mDBConn->CreateStatement(NS_LITERAL_CSTRING(
+    "SELECT id "
+    "FROM moz_downloads "
+    "WHERE state = ?1 "
+      "AND LENGTH(entityID) > 0"), getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->BindInt32Parameter(0, nsIDownloadManager::DOWNLOAD_PAUSED);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  PRBool hasResults;
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResults)) && hasResults) {
+    nsRefPtr<nsDownload> dl;
+    // Keep trying to add even if we fail one, but make sure to return failure.
+    // Additionally, be careful to not call anything that tries to change the
+    // database because we're iterating over a live statement.
+    if (NS_FAILED(GetDownloadFromDB(stmt->AsInt32(0), getter_AddRefs(dl))) ||
+        NS_FAILED(AddToCurrentDownloads(dl)))
+      rv = NS_ERROR_FAILURE;
+  }
+  return rv;
+}
+
 PRInt64
 nsDownloadManager::AddDownloadToDB(const nsAString &aName,
                                    const nsACString &aSource,
@@ -718,6 +751,9 @@ nsDownloadManager::Init()
   rv = RestoreDatabaseState();
   NS_ENSURE_SUCCESS(rv, rv);
 
+  rv = RestoreActiveDownloads();
+  NS_ENSURE_SUCCESS(rv, rv);
+
   nsCOMPtr<nsIStringBundleService> bundleService =
     do_GetService(NS_STRINGBUNDLE_CONTRACTID, &rv);
   NS_ENSURE_SUCCESS(rv, rv);
@@ -1412,7 +1448,11 @@ nsDownloadManager::Observe(nsISupports *aSubject,
                            const char *aTopic,
                            const PRUnichar *aData)
 {
-  PRInt32 currDownloadCount = mCurrentDownloads.Count();
+  // Count active downloads that aren't real-paused
+  PRInt32 currDownloadCount = 0;
+  for (PRInt32 i = mCurrentDownloads.Count() - 1; i >= 0; --i)
+    if (!mCurrentDownloads[i]->IsRealPaused())
+      currDownloadCount++;
 
   nsresult rv;
   if (strcmp(aTopic, "oncancel") == 0) {
@@ -1428,7 +1468,7 @@ nsDownloadManager::Observe(nsISupports *aSubject,
     gStoppingDownloads = PR_TRUE;
 
     if (currDownloadCount)
-      CancelAllDownloads();
+      (void)RemoveAllDownloads();
 
     // Now that active downloads have been canceled, remove all downloads if
     // the user's retention policy specifies it.

toolkit/components/downloads/src/nsDownloadManager.h

@@ -24,6 +24,7 @@
  *   Ben Goodger <ben@netscape.com>
  *   Shawn Wilsher <me@shawnwilsher.com>
  *   Srirang G Doddihal <brahmana@doddihal.com>
+ *   Edward Lee <edward.lee@engineering.uiuc.edu>
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
@@ -99,6 +100,13 @@ protected:
   nsresult CreateTable();
   nsresult ImportDownloadHistory();
   nsresult RestoreDatabaseState();
+
+  /**
+   * Paused downloads that survive across sessions are considered active, so
+   * rebuild the list of these downloads.
+   */
+  nsresult RestoreActiveDownloads();
+
   nsresult GetDownloadFromDB(PRUint32 aID, nsDownload **retVal);
 
   /**
@@ -138,7 +146,14 @@ protected:
                                     nsIDownload *aDownload);
 
   nsDownload *FindDownload(PRUint32 aID);
-  nsresult CancelAllDownloads();
+
+  /**
+   * Stop tracking the active downloads. Only use this when we're about to quit
+   * the download manager because we destroy our list of active downloads to
+   * break the dlmgr<->dl cycle. Active downloads that aren't real-paused will
+   * be canceled.
+   */
+  nsresult RemoveAllDownloads();
 
   /**
    * Removes download from "current downloads".