Bug 1790641 - Only delete downloaded files in private browsing if deletePrivate pref is set to true - r=mconley,fluent-reviewers,settings-reviewers,desktop-theme-reviewers,hjones,bolsson,mossop

Differential Revision: https://phabricator.services.mozilla.com/D230168

Author: Rebecca King

browser/components/customizableui/PanelMultiView.sys.mjs

@@ -1100,7 +1100,9 @@ export var PanelMultiView = class extends AssociatedToNode {
 
     // Avoid transforming element if the user has prefers-reduced-motion set
     if (
-      this.window.matchMedia("(prefers-reduced-motion: no-preference)").matches
+      this.window.matchMedia("(prefers-reduced-motion: no-preference)")
+        .matches &&
+      !viewNode.getAttribute("no-panelview-transition")
     ) {
       this._viewStack.style.transform =
         "translateX(" + (moveToLeft ? "" : "-") + deltaX + "px)";

browser/components/downloads/content/downloads.js

@@ -40,6 +40,7 @@ ChromeUtils.defineESModuleGetters(this, {
   FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
   NetUtil: "resource://gre/modules/NetUtil.sys.mjs",
   PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.sys.mjs",
 });
 
 const { Integration } = ChromeUtils.importESModule(
@@ -710,6 +711,24 @@ var DownloadsPanel = {
         if (!this._openedManually) {
           this._delayPopupItems();
         }
+
+        let isPrivate =
+          window && PrivateBrowsingUtils.isContentWindowPrivate(window);
+
+        if (
+          // If private, show message asking whether to delete files at end of session
+          isPrivate &&
+          Services.prefs.getBoolPref(
+            "browser.download.enableDeletePrivate",
+            false
+          ) &&
+          !Services.prefs.getBoolPref(
+            "browser.download.deletePrivate.chosen",
+            false
+          )
+        ) {
+          PrivateDownloadsSubview.openWhenReady();
+        }
       }, console.error);
     }, 0);
   },
@@ -1343,7 +1362,11 @@ var DownloadsViewController = {
   // nsIController
 
   supportsCommand(aCommand) {
-    if (aCommand === "downloadsCmd_clearList") {
+    if (
+      aCommand === "downloadsCmd_clearList" ||
+      aCommand === "downloadsCmd_deletePrivate" ||
+      aCommand === "downloadsCmd_dismissDeletePrivate"
+    ) {
       return true;
     }
     // Firstly, determine if this is a command that we can handle.
@@ -1379,16 +1402,22 @@ var DownloadsViewController = {
 
   isCommandEnabled(aCommand) {
     // Handle commands that are not selection-specific.
-    if (aCommand == "downloadsCmd_clearList") {
-      return DownloadsCommon.getData(window).canRemoveFinished;
+    switch (aCommand) {
+      case "downloadsCmd_clearList": {
+        return DownloadsCommon.getData(window).canRemoveFinished;
+      }
+      case "downloadsCmd_deletePrivate":
+      case "downloadsCmd_dismissDeletePrivate":
+        return true;
+      default: {
+        // Other commands are selection-specific.
+        let element = DownloadsView.richListBox.selectedItem;
+        return (
+          element &&
+          DownloadsView.itemForElement(element).isCommandEnabled(aCommand)
+        );
+      }
     }
-
-    // Other commands are selection-specific.
-    let element = DownloadsView.richListBox.selectedItem;
-    return (
-      element &&
-      DownloadsView.itemForElement(element).isCommandEnabled(aCommand)
-    );
   },
 
   doCommand(aCommand) {
@@ -1427,6 +1456,14 @@ var DownloadsViewController = {
   downloadsCmd_clearList() {
     DownloadsCommon.getData(window).removeFinished();
   },
+
+  downloadsCmd_deletePrivate() {
+    PrivateDownloadsSubview.choose(true /* deletePrivate */);
+  },
+
+  downloadsCmd_dismissDeletePrivate() {
+    PrivateDownloadsSubview.choose(false /* deletePrivate */);
+  },
 };
 
 XPCOMUtils.defineConstant(
@@ -1781,3 +1818,66 @@ XPCOMUtils.defineConstant(
   "DownloadsBlockedSubview",
   DownloadsBlockedSubview
 );
+
+/**
+ * Manages the private browsing downloads subview that appears when you download a file in private browsing mode
+ */
+var PrivateDownloadsSubview = {
+  /**
+   * Slides in the private downloads subview.
+   *
+   * @param element
+   *        The download richlistitem element that was clicked.
+   */
+  openWhenReady() {
+    DownloadsView.subViewOpen = true;
+    DownloadsViewController.updateCommands();
+
+    this.mainView.addEventListener("ViewShown", this, { once: true });
+    this.mainView.toggleAttribute("showing-private-browsing-choice", true);
+  },
+
+  handleEvent(event) {
+    // This is called when the main view is shown or the panel is hidden.
+
+    // Focus the proper element if we're going back to the main panel.
+    if (event.type == "ViewShown") {
+      this.panelMultiView.showSubView(this.subview);
+    }
+  },
+
+  /**
+   * Sets whether to delete files at the end of private download session
+   * Based on user response to download notification prompt
+   *
+   * @param deletePrivate
+   *        True if the user chose to delete files at the end of the session
+   */
+  choose(deletePrivate) {
+    if (deletePrivate) {
+      Services.prefs.setBoolPref("browser.download.deletePrivate", true);
+    }
+    Services.prefs.setBoolPref("browser.download.deletePrivate.chosen", true);
+    DownloadsView.subViewOpen = false;
+    this.mainView.toggleAttribute("showing-private-browsing-choice", false);
+    this.panelMultiView.goBack();
+  },
+};
+
+ChromeUtils.defineLazyGetter(PrivateDownloadsSubview, "panelMultiView", () =>
+  document.getElementById("downloadsPanel-multiView")
+);
+
+ChromeUtils.defineLazyGetter(PrivateDownloadsSubview, "mainView", () =>
+  document.getElementById("downloadsPanel-mainView")
+);
+
+ChromeUtils.defineLazyGetter(PrivateDownloadsSubview, "subview", () =>
+  document.getElementById("downloadsPanel-privateBrowsing")
+);
+
+XPCOMUtils.defineConstant(
+  this,
+  "PrivateDownloadsSubview",
+  PrivateDownloadsSubview
+);

browser/components/downloads/content/downloadsPanel.inc.xhtml

@@ -27,6 +27,8 @@
   <command id="downloadsCmd_alwaysOpenInSystemViewer" />
   <command id="downloadsCmd_alwaysOpenSimilarFiles" />
   <command id="downloadsCmd_deleteFile" />
+  <command id="downloadsCmd_deletePrivate"/>
+  <command id="downloadsCmd_dismissDeletePrivate"/>
 </commandset>
 
 <!-- For accessibility to screen readers, we use a label on the panel instead
@@ -159,6 +161,32 @@
                 default="true"/>
       </html:moz-button-group>
     </panelview>
+
+    <panelview id="downloadsPanel-privateBrowsing"
+               class="PanelUI-subview"
+               data-l10n-id="downloads-private-browsing-details"
+               no-panelview-transition="true"
+               has-custom-header="true"
+               no-back-button="true">
+      <box class="panel-header panel-header-with-additional-element">
+        <html:h1>
+          <html:span/>
+        </html:h1>
+      </box>
+      <vbox class="panel-view-body-unscrollable">
+        <description data-l10n-id="downloads-private-browsing-message"/>
+      </vbox>
+      <html:moz-button-group
+          class="panel-footer">
+        <button class="footer-button secondary"
+                command="downloadsCmd_deletePrivate"
+                data-l10n-id="downloads-private-browsing-delete-button"/>
+        <button class="footer-button primary"
+                default="true"
+                command="downloadsCmd_dismissDeletePrivate"
+                data-l10n-id="downloads-private-browsing-accept-button"/>
+    </html:moz-button-group>
+    </panelview>
   </panelmultiview>
 
 </panel>

browser/components/preferences/main.inc.xhtml

@@ -492,6 +492,9 @@
   <checkbox id="alwaysAsk"
             data-l10n-id="download-always-ask-where"
             preference="browser.download.useDownloadDir"/>
+            <checkbox id="deletePrivate"
+            data-l10n-id="download-private-browsing-delete"
+            preference="browser.download.deletePrivate"/>
 </groupbox>
 
 <groupbox id="applicationsGroup" data-category="paneGeneral" hidden="true">

browser/components/preferences/main.js

@@ -57,6 +57,7 @@ Preferences.addAll([
 
   // Downloads
   { id: "browser.download.useDownloadDir", type: "bool", inverted: true },
+  { id: "browser.download.deletePrivate", type: "bool" },
   { id: "browser.download.always_ask_before_handling_new_types", type: "bool" },
   { id: "browser.download.folderList", type: "int" },
   { id: "browser.download.dir", type: "file" },
@@ -739,6 +740,11 @@ var gMainPane = {
       "command",
       gMainPane.onMigrationButtonCommand
     );
+    setEventListener(
+      "deletePrivate",
+      "command",
+      gMainPane.onDeletePrivateChanged
+    );
 
     document
       .getElementById("migrationWizardDialog")
@@ -1032,6 +1038,11 @@ var gMainPane = {
       () => this.readBrowserContainersCheckbox()
     );
 
+    if (!Services.prefs.getBoolPref("browser.download.enableDeletePrivate")) {
+      let deletePrivateCheckbox = document.getElementById("deletePrivate");
+      deletePrivateCheckbox.hidden = true;
+    }
+
     this.setInitialized();
   },
 
@@ -2453,6 +2464,10 @@ var gMainPane = {
     });
   },
 
+  onDeletePrivateChanged() {
+    Services.prefs.setBoolPref("browser.download.deletePrivate.chosen", true);
+  },
+
   /**
    * Displays the migration wizard dialog in an HTML dialog.
    */
@@ -3667,7 +3682,12 @@ var gMainPane = {
    *   True - Save files directly to the folder configured via the
    *   browser.download.folderList preference.
    *   False - Always ask the user where to save a file and default to
-   *   browser.download.lastDir when displaying a folder picker dialog.
+   *  browser.download.lastDir when displaying a folder picker dialog.
+   *  browser.download.deletePrivate - bool
+   *   True - Delete files that were downloaded in a private browsing session
+   *   on close of the session
+   *   False - Keep files that were downloaded in a private browsing
+   *   session
    * browser.download.always_ask_before_handling_new_types - bool
    *   Defines the default behavior for new file handlers.
    *   True - When downloading a file that doesn't match any existing

browser/locales/en-US/browser/downloads.ftl

@@ -194,6 +194,18 @@ downloads-history =
 downloads-details =
     .title = Download details
 
+## These strings are displayed in the private browsing view of the downloads panel
+
+downloads-private-browsing-details =
+  .title = Files stay on your device
+downloads-private-browsing-message = Anyone using this device can see downloads, even when you close all private windows.
+downloads-private-browsing-delete-button =
+  .label = Delete files automatically
+  .accesskey = D
+downloads-private-browsing-accept-button =
+  .label = Got it
+  .accesskey = G
+
 ## Displayed when a site attempts to automatically download many files.
 ## Variables:
 ##   $num (number) - Number of blocked downloads.

browser/locales/en-US/browser/preferences/preferences.ftl

@@ -408,6 +408,9 @@ download-choose-folder =
 download-always-ask-where =
     .label = Always ask you where to save files
     .accesskey = A
+download-private-browsing-delete =
+    .label = Delete files downloaded in private browsing when all private windows are closed
+    .accesskey = D
 
 applications-header = Applications
 

browser/themes/shared/downloads/downloads.inc.css

@@ -261,3 +261,20 @@
 #downloadsFooterButtons > toolbarseparator {
   margin-inline: 0;
 }
+
+/*** Delete files in private browsing subview ***/
+#downloadsPanel-mainView[showing-private-browsing-choice] > .panel-view-body-unscrollable > #downloadsListBox > richlistitem {
+  display: none;
+}
+
+#downloadsPanel-privateBrowsing {
+  padding-inline-start: var(--space-medium);
+}
+
+#downloadsPanel-privateBrowsing > .panel-header {
+  text-align: start;
+}
+
+#downloadsPanel-privateBrowsing > toolbarseparator {
+  display: none;
+}

modules/libpref/init/StaticPrefList.yaml

@@ -1593,6 +1593,22 @@
   value: false
   mirror: always
 
+# See bug 1790641
+- name: browser.download.enableDeletePrivate
+  type: bool
+  value: false
+  mirror: always
+
+- name: browser.download.deletePrivate
+  type: bool
+  value: false
+  mirror: always
+
+- name: browser.download.deletePrivateChosen
+  type: bool
+  value: false
+  mirror: always
+
 # See bug 1731668
 - name: browser.download.enable_spam_prevention
   type: bool

toolkit/components/downloads/DownloadCore.sys.mjs

@@ -640,8 +640,6 @@ Download.prototype = {
     if (this.launchWhenSucceeded) {
       this.launch().catch(console.error);
 
-      // Always schedule files to be deleted at the end of the private browsing
-      // mode, regardless of the value of the pref.
       if (this.source.isPrivate) {
         lazy.gExternalAppLauncher.deleteTemporaryPrivateFileWhenPossible(
           new lazy.FileUtils.File(this.target.path)
@@ -658,6 +656,19 @@ Download.prototype = {
         );
       }
     }
+
+    if (
+      Services.prefs.getBoolPref(
+        "browser.download.enableDeletePrivate",
+        false
+      ) &&
+      Services.prefs.getBoolPref("browser.download.deletePrivate", false) &&
+      this.source.isPrivate
+    ) {
+      lazy.gExternalAppLauncher.deletePrivateFileWhenPossible(
+        new lazy.FileUtils.File(this.target.path)
+      );
+    }
   },
 
   /**