Add m-esr52 at 52.6.0

1 files changed, 203 insertions, 0 deletions

diff --git a/toolkit/components/jsdownloads/src/DownloadStore.jsm b/toolkit/components/jsdownloads/src/DownloadStore.jsm
new file mode 100644
index 000000000..765a45c5a
--- /dev/null
+++ b/toolkit/components/jsdownloads/src/DownloadStore.jsm
@@ -0,0 +1,203 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Handles serialization of Download objects and persistence into a file, so
+ * that the state of downloads can be restored across sessions.
+ *
+ * The file is stored in JSON format, without indentation.  With indentation
+ * applied, the file would look like this:
+ *
+ * {
+ *   "list": [
+ *     {
+ *       "source": "http://www.example.com/download.txt",
+ *       "target": "/home/user/Downloads/download.txt"
+ *     },
+ *     {
+ *       "source": {
+ *         "url": "http://www.example.com/download.txt",
+ *         "referrer": "http://www.example.com/referrer.html"
+ *       },
+ *       "target": "/home/user/Downloads/download-2.txt"
+ *     }
+ *   ]
+ * }
+ */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = [
+  "DownloadStore",
+];
+
+// Globals
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+const Cr = Components.results;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Downloads",
+                                  "resource://gre/modules/Downloads.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "OS",
+                                  "resource://gre/modules/osfile.jsm")
+XPCOMUtils.defineLazyModuleGetter(this, "Task",
+                                  "resource://gre/modules/Task.jsm");
+
+XPCOMUtils.defineLazyGetter(this, "gTextDecoder", function () {
+  return new TextDecoder();
+});
+
+XPCOMUtils.defineLazyGetter(this, "gTextEncoder", function () {
+  return new TextEncoder();
+});
+
+// DownloadStore
+
+/**
+ * Handles serialization of Download objects and persistence into a file, so
+ * that the state of downloads can be restored across sessions.
+ *
+ * @param aList
+ *        DownloadList object to be populated or serialized.
+ * @param aPath
+ *        String containing the file path where data should be saved.
+ */
+this.DownloadStore = function (aList, aPath)
+{
+  this.list = aList;
+  this.path = aPath;
+}
+
+this.DownloadStore.prototype = {
+  /**
+   * DownloadList object to be populated or serialized.
+   */
+  list: null,
+
+  /**
+   * String containing the file path where data should be saved.
+   */
+  path: "",
+
+  /**
+   * This function is called with a Download object as its first argument, and
+   * should return true if the item should be saved.
+   */
+  onsaveitem: () => true,
+
+  /**
+   * Loads persistent downloads from the file to the list.
+   *
+   * @return {Promise}
+   * @resolves When the operation finished successfully.
+   * @rejects JavaScript exception.
+   */
+  load: function DS_load()
+  {
+    return Task.spawn(function* task_DS_load() {
+      let bytes;
+      try {
+        bytes = yield OS.File.read(this.path);
+      } catch (ex) {
+        if (!(ex instanceof OS.File.Error) || !ex.becauseNoSuchFile) {
+          throw ex;
+        }
+        // If the file does not exist, there are no downloads to load.
+        return;
+      }
+
+      let storeData = JSON.parse(gTextDecoder.decode(bytes));
+
+      // Create live downloads based on the static snapshot.
+      for (let downloadData of storeData.list) {
+        try {
+          let download = yield Downloads.createDownload(downloadData);
+          try {
+            if (!download.succeeded && !download.canceled && !download.error) {
+              // Try to restart the download if it was in progress during the
+              // previous session.  Ignore errors.
+              download.start().catch(() => {});
+            } else {
+              // If the download was not in progress, try to update the current
+              // progress from disk.  This is relevant in case we retained
+              // partially downloaded data.
+              yield download.refresh();
+            }
+          } finally {
+            // Add the download to the list if we succeeded in creating it,
+            // after we have updated its initial state.
+            yield this.list.add(download);
+          }
+        } catch (ex) {
+          // If an item is unrecognized, don't prevent others from being loaded.
+          Cu.reportError(ex);
+        }
+      }
+    }.bind(this));
+  },
+
+  /**
+   * Saves persistent downloads from the list to the file.
+   *
+   * If an error occurs, the previous file is not deleted.
+   *
+   * @return {Promise}
+   * @resolves When the operation finished successfully.
+   * @rejects JavaScript exception.
+   */
+  save: function DS_save()
+  {
+    return Task.spawn(function* task_DS_save() {
+      let downloads = yield this.list.getAll();
+
+      // Take a static snapshot of the current state of all the downloads.
+      let storeData = { list: [] };
+      let atLeastOneDownload = false;
+      for (let download of downloads) {
+        try {
+          if (!this.onsaveitem(download)) {
+            continue;
+          }
+
+          let serializable = download.toSerializable();
+          if (!serializable) {
+            // This item cannot be persisted across sessions.
+            continue;
+          }
+          storeData.list.push(serializable);
+          atLeastOneDownload = true;
+        } catch (ex) {
+          // If an item cannot be converted to a serializable form, don't
+          // prevent others from being saved.
+          Cu.reportError(ex);
+        }
+      }
+
+      if (atLeastOneDownload) {
+        // Create or overwrite the file if there are downloads to save.
+        let bytes = gTextEncoder.encode(JSON.stringify(storeData));
+        yield OS.File.writeAtomic(this.path, bytes,
+                                  { tmpPath: this.path + ".tmp" });
+      } else {
+        // Remove the file if there are no downloads to save at all.
+        try {
+          yield OS.File.remove(this.path);
+        } catch (ex) {
+          if (!(ex instanceof OS.File.Error) ||
+              !(ex.becauseNoSuchFile || ex.becauseAccessDenied)) {
+            throw ex;
+          }
+          // On Windows, we may get an access denied error instead of a no such
+          // file error if the file existed before, and was recently deleted.
+        }
+      }
+    }.bind(this));
+  },
+};