Add support to launch element picker in embedded frames

Related issue:
- https://github.com/gorhill/uBlock/issues/1744

A new context menu entry, "Block element in frame...", will
be present when right-clicking on a frame element. When
this entry is clicked, uBO's element picker will be
launched from within the embedded frame and function the
same way as when launched from within the page.

platform/chromium/vapi-background.js

@@ -1010,6 +1010,7 @@ vAPI.messaging = {
         case 'extendClient':
             vAPI.tabs.executeScript(tabId, {
                 file: '/js/vapi-client-extra.js',
+                frameId: portDetails.frameId,
             }).then(( ) => {
                 callback();
             });

src/_locales/en/messages.json

@@ -1027,6 +1027,10 @@
     "message": "bytes",
     "description": ""
   },
+  "contextMenuBlockElementInFrame": {
+    "message": "Block element in frame...",
+    "description": "An entry in the browser's contextual menu"
+  },
   "contextMenuTemporarilyAllowLargeMediaElements": {
     "message": "Temporarily allow large media elements",
     "description": "A context menu entry, present when large media elements have been blocked on the current site"

src/css/epicker-ui.css

@@ -15,16 +15,18 @@ html#ublock0-epicker,
 #ublock0-epicker aside {
     background-color: var(--default-surface);
     border: 1px solid var(--default-surface-border);
-    bottom: 4px;
+    bottom: 2px;
     box-sizing: border-box;
     cursor: default;
     display: none;
+    max-height: calc(100vh - 4px);
     max-width: 36rem;
     min-width: 24rem;
+    overflow-y: auto;
     padding: 4px;
     position: fixed;
-    right: 4px;
-    width: calc(40% - 4px);
+    right: 2px;
+    width: calc(40% - 2px);
 }
 #ublock0-epicker.paused:not(.zap) aside {
     display: block;
@@ -89,6 +91,8 @@ html#ublock0-epicker,
     box-sizing: border-box;
     font: 11px monospace;
     height: 8em;
+    max-height: 50vh;
+    min-height: 1em;
     padding: 2px;
     width: 100%;
     }

src/js/commands.js

@@ -165,6 +165,7 @@ vAPI.commands.onCommand.addListener(async command => {
         µb.epickerArgs.mouse = false;
         µb.elementPickerExec(
             tab.id,
+            0,
             undefined,
             command === 'launch-element-zapper'
         );

src/js/contextmenu.js

@@ -58,7 +58,16 @@ const onBlockElement = function(details, tab) {
     }
 
     µBlock.epickerArgs.mouse = true;
-    µBlock.elementPickerExec(tab.id, tagName + '\t' + src);
+    µBlock.elementPickerExec(tab.id, 0, `${tagName}\t${src}`);
+};
+
+/******************************************************************************/
+
+const onBlockElementInFrame = function(details, tab) {
+    if ( tab === undefined ) { return; }
+    if ( /^https?:\/\//.test(details.frameUrl) === false ) { return; }
+    µBlock.epickerArgs.mouse = false;
+    µBlock.elementPickerExec(tab.id, details.frameId);
 };
 
 /******************************************************************************/
@@ -76,6 +85,9 @@ const onEntryClicked = function(details, tab) {
     if ( details.menuItemId === 'uBlock0-blockElement' ) {
         return onBlockElement(details, tab);
     }
+    if ( details.menuItemId === 'uBlock0-blockElementInFrame' ) {
+        return onBlockElementInFrame(details, tab);
+    }
     if ( details.menuItemId === 'uBlock0-temporarilyAllowLargeMediaElements' ) {
         return onTemporarilyAllowLargeMediaElements(details, tab);
     }
@@ -83,18 +95,23 @@ const onEntryClicked = function(details, tab) {
 
 /******************************************************************************/
 
-const menuEntries = [
-    {
+const menuEntries = {
+    blockElement: {
         id: 'uBlock0-blockElement',
         title: vAPI.i18n('pickerContextMenuEntry'),
         contexts: ['all'],
     },
-    {
+    blockElementInFrame: {
+        id: 'uBlock0-blockElementInFrame',
+        title: vAPI.i18n('contextMenuBlockElementInFrame'),
+        contexts: ['frame'],
+    },
+    temporarilyAllowLargeMediaElements: {
         id: 'uBlock0-temporarilyAllowLargeMediaElements',
         title: vAPI.i18n('contextMenuTemporarilyAllowLargeMediaElements'),
         contexts: ['all'],
     }
-];
+};
 
 /******************************************************************************/
 
@@ -115,10 +132,11 @@ const update = function(tabId = undefined) {
     currentBits = newBits;
     let usedEntries = [];
     if ( newBits & 0x01 ) {
-        usedEntries.push(menuEntries[0]);
+        usedEntries.push(menuEntries.blockElement);
+        usedEntries.push(menuEntries.blockElementInFrame);
     }
     if ( newBits & 0x02 ) {
-        usedEntries.push(menuEntries[1]);
+        usedEntries.push(menuEntries.temporarilyAllowLargeMediaElements);
     }
     vAPI.contextMenu.setEntries(usedEntries, onEntryClicked);
 };

src/js/epicker-ui.js

@@ -599,8 +599,8 @@ const onStartMoving = (( ) => {
 
     const move = ( ) => {
         timer = undefined;
-        const r1 = Math.min(Math.max(r0 - mx1 + mx0, 4), rMax);
-        const b1 = Math.min(Math.max(b0 - my1 + my0, 4), bMax);
+        const r1 = Math.min(Math.max(r0 - mx1 + mx0, 2), rMax);
+        const b1 = Math.min(Math.max(b0 - my1 + my0, 2), bMax);
         dialog.style.setProperty('right', `${r1}px`);
         dialog.style.setProperty('bottom', `${b1}px`);
     };
@@ -646,8 +646,8 @@ const onStartMoving = (( ) => {
         r0 = parseInt(style.right, 10);
         b0 = parseInt(style.bottom, 10);
         const rect = dialog.getBoundingClientRect();
-        rMax = pickerRoot.clientWidth - 4 - rect.width ;
-        bMax = pickerRoot.clientHeight - 4 - rect.height;
+        rMax = pickerRoot.clientWidth - 2 - rect.width ;
+        bMax = pickerRoot.clientHeight - 2 - rect.height;
         dialog.classList.add('moving');
         if ( isTouch ) {
             self.addEventListener('touchmove', moveAsync, { capture: true });

src/js/messaging.js

@@ -154,7 +154,7 @@ const onMessage = function(request, sender, callback) {
     case 'launchElementPicker':
         // Launched from some auxiliary pages, clear context menu coords.
         µb.epickerArgs.mouse = false;
-        µb.elementPickerExec(request.tabId, request.targetURL, request.zap);
+        µb.elementPickerExec(request.tabId, 0, request.targetURL, request.zap);
         break;
 
     case 'gotoURL':

src/js/ublock.js

@@ -414,7 +414,12 @@ const matchBucket = function(url, hostname, bucket, start) {
 
 /******************************************************************************/
 
-µBlock.elementPickerExec = async function(tabId, targetElement, zap = false) {
+µBlock.elementPickerExec = async function(
+    tabId,
+    frameId,
+    targetElement,
+    zap = false,
+) {
     if ( vAPI.isBehindTheSceneTabId(tabId) ) { return; }
 
     this.epickerArgs.target = targetElement || '';
@@ -422,13 +427,16 @@ const matchBucket = function(url, hostname, bucket, start) {
 
     // https://github.com/uBlockOrigin/uBlock-issues/issues/40
     //   The element picker needs this library
-    vAPI.tabs.executeScript(tabId, {
-        file: '/lib/diff/swatinem_diff.js',
-        runAt: 'document_end',
-    });
+    if ( zap !== true ) {
+        vAPI.tabs.executeScript(tabId, {
+            file: '/lib/diff/swatinem_diff.js',
+            runAt: 'document_end',
+        });
+    }
 
     await vAPI.tabs.executeScript(tabId, {
         file: '/js/scriptlets/epicker.js',
+        frameId,
         runAt: 'document_end',
     });