1 files changed, 308 insertions, 0 deletions
diff --git a/devtools/client/shared/key-shortcuts.js b/devtools/client/shared/key-shortcuts.js
new file mode 100644
index 0000000000..35905fdc35
--- /dev/null
+++ b/devtools/client/shared/key-shortcuts.js
@@ -0,0 +1,308 @@
+/* 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/. */
+
+"use strict";
+
+const EventEmitter = require("resource://devtools/shared/event-emitter.js");
+const isOSX = Services.appinfo.OS === "Darwin";
+const { KeyCodes } = require("resource://devtools/client/shared/keycodes.js");
+
+// List of electron keys mapped to DOM API (DOM_VK_*) key code
+const ElectronKeysMapping = {
+  F1: "DOM_VK_F1",
+  F2: "DOM_VK_F2",
+  F3: "DOM_VK_F3",
+  F4: "DOM_VK_F4",
+  F5: "DOM_VK_F5",
+  F6: "DOM_VK_F6",
+  F7: "DOM_VK_F7",
+  F8: "DOM_VK_F8",
+  F9: "DOM_VK_F9",
+  F10: "DOM_VK_F10",
+  F11: "DOM_VK_F11",
+  F12: "DOM_VK_F12",
+  F13: "DOM_VK_F13",
+  F14: "DOM_VK_F14",
+  F15: "DOM_VK_F15",
+  F16: "DOM_VK_F16",
+  F17: "DOM_VK_F17",
+  F18: "DOM_VK_F18",
+  F19: "DOM_VK_F19",
+  F20: "DOM_VK_F20",
+  F21: "DOM_VK_F21",
+  F22: "DOM_VK_F22",
+  F23: "DOM_VK_F23",
+  F24: "DOM_VK_F24",
+  Space: "DOM_VK_SPACE",
+  Backspace: "DOM_VK_BACK_SPACE",
+  Delete: "DOM_VK_DELETE",
+  Insert: "DOM_VK_INSERT",
+  Return: "DOM_VK_RETURN",
+  Enter: "DOM_VK_RETURN",
+  Up: "DOM_VK_UP",
+  Down: "DOM_VK_DOWN",
+  Left: "DOM_VK_LEFT",
+  Right: "DOM_VK_RIGHT",
+  Home: "DOM_VK_HOME",
+  End: "DOM_VK_END",
+  PageUp: "DOM_VK_PAGE_UP",
+  PageDown: "DOM_VK_PAGE_DOWN",
+  Escape: "DOM_VK_ESCAPE",
+  Esc: "DOM_VK_ESCAPE",
+  Tab: "DOM_VK_TAB",
+  VolumeUp: "DOM_VK_VOLUME_UP",
+  VolumeDown: "DOM_VK_VOLUME_DOWN",
+  VolumeMute: "DOM_VK_VOLUME_MUTE",
+  PrintScreen: "DOM_VK_PRINTSCREEN",
+};
+
+/**
+ * Helper to listen for keyboard events described in .properties file.
+ *
+ * let shortcuts = new KeyShortcuts({
+ *   window
+ * });
+ * shortcuts.on("Ctrl+F", event => {
+ *   // `event` is the KeyboardEvent which relates to the key shortcuts
+ * });
+ *
+ * @param DOMWindow window
+ *        The window object of the document to listen events from.
+ * @param DOMElement target
+ *        Optional DOM Element on which we should listen events from.
+ *        If omitted, we listen for all events fired on `window`.
+ */
+function KeyShortcuts({ window, target }) {
+  this.window = window;
+  this.target = target || window;
+  this.keys = new Map();
+  this.eventEmitter = new EventEmitter();
+  this.target.addEventListener("keydown", this);
+}
+
+/*
+ * Parse an electron-like key string and return a normalized object which
+ * allow efficient match on DOM key event. The normalized object matches DOM
+ * API.
+ *
+ * @param DOMWindow window
+ *        Any DOM Window object, just to fetch its `KeyboardEvent` object
+ * @param String str
+ *        The shortcut string to parse, following this document:
+ *        https://github.com/electron/electron/blob/master/docs/api/accelerator.md
+ */
+KeyShortcuts.parseElectronKey = function (window, str) {
+  // If a localized string is found but has no value in the properties file,
+  // getStr will return `null`. See Bug 1569572.
+  if (typeof str !== "string") {
+    console.error("Invalid key passed to parseElectronKey, stacktrace below");
+    console.trace();
+
+    return null;
+  }
+
+  const modifiers = str.split("+");
+  let key = modifiers.pop();
+
+  const shortcut = {
+    ctrl: false,
+    meta: false,
+    alt: false,
+    shift: false,
+    // Set for character keys
+    key: undefined,
+    // Set for non-character keys
+    keyCode: undefined,
+  };
+  for (const mod of modifiers) {
+    if (mod === "Alt") {
+      shortcut.alt = true;
+    } else if (["Command", "Cmd"].includes(mod)) {
+      shortcut.meta = true;
+    } else if (["CommandOrControl", "CmdOrCtrl"].includes(mod)) {
+      if (isOSX) {
+        shortcut.meta = true;
+      } else {
+        shortcut.ctrl = true;
+      }
+    } else if (["Control", "Ctrl"].includes(mod)) {
+      shortcut.ctrl = true;
+    } else if (mod === "Shift") {
+      shortcut.shift = true;
+    } else {
+      console.error("Unsupported modifier:", mod, "from key:", str);
+      return null;
+    }
+  }
+
+  // Plus is a special case. It's a character key and shouldn't be matched
+  // against a keycode as it is only accessible via Shift/Capslock
+  if (key === "Plus") {
+    key = "+";
+  }
+
+  if (typeof key === "string" && key.length === 1) {
+    if (shortcut.alt) {
+      // When Alt is involved, some platforms (macOS) give different printable characters
+      // for the `key` value, like `®` for the key `R`.  In this case, prefer matching by
+      // `keyCode` instead.
+      shortcut.keyCode = KeyCodes[`DOM_VK_${key.toUpperCase()}`];
+      shortcut.keyCodeString = key;
+    } else {
+      // Match any single character
+      shortcut.key = key.toLowerCase();
+    }
+  } else if (key in ElectronKeysMapping) {
+    // Maps the others manually to DOM API DOM_VK_*
+    key = ElectronKeysMapping[key];
+    shortcut.keyCode = KeyCodes[key];
+    // Used only to stringify the shortcut
+    shortcut.keyCodeString = key;
+    shortcut.key = key;
+  } else {
+    console.error("Unsupported key:", key);
+    return null;
+  }
+
+  return shortcut;
+};
+
+KeyShortcuts.stringify = function (shortcut) {
+  if (shortcut === null) {
+    // parseElectronKey might return null in several situations.
+    return "";
+  }
+
+  const list = [];
+  if (shortcut.alt) {
+    list.push("Alt");
+  }
+  if (shortcut.ctrl) {
+    list.push("Ctrl");
+  }
+  if (shortcut.meta) {
+    list.push("Cmd");
+  }
+  if (shortcut.shift) {
+    list.push("Shift");
+  }
+  let key;
+  if (shortcut.key) {
+    key = shortcut.key.toUpperCase();
+  } else {
+    key = shortcut.keyCodeString;
+  }
+  list.push(key);
+  return list.join("+");
+};
+
+/*
+ * Parse an xul-like key string and return an electron-like string.
+ */
+KeyShortcuts.parseXulKey = function (modifiers, shortcut) {
+  modifiers = modifiers
+    .split(",")
+    .map(mod => {
+      if (mod == "alt") {
+        return "Alt";
+      } else if (mod == "shift") {
+        return "Shift";
+      } else if (mod == "accel") {
+        return "CmdOrCtrl";
+      }
+      return mod;
+    })
+    .join("+");
+
+  if (shortcut.startsWith("VK_")) {
+    shortcut = shortcut.substr(3);
+  }
+
+  return modifiers + "+" + shortcut;
+};
+
+KeyShortcuts.prototype = {
+  destroy() {
+    this.target.removeEventListener("keydown", this);
+    this.keys.clear();
+  },
+
+  doesEventMatchShortcut(event, shortcut) {
+    if (shortcut.meta != event.metaKey) {
+      return false;
+    }
+    if (shortcut.ctrl != event.ctrlKey) {
+      return false;
+    }
+    if (shortcut.alt != event.altKey) {
+      return false;
+    }
+    if (shortcut.shift != event.shiftKey) {
+      // Check the `keyCode` to see whether it's a character (see also Bug 1493646)
+      const char = String.fromCharCode(event.keyCode);
+      let isAlphabetical = char.length == 1 && char.match(/[a-zA-Z]/);
+
+      // Shift is a special modifier, it may implicitly be required if the expected key
+      // is a special character accessible via shift.
+      if (!isAlphabetical) {
+        isAlphabetical = event.key && event.key.match(/[a-zA-Z]/);
+      }
+
+      // OSX: distinguish cmd+[key] from cmd+shift+[key] shortcuts (Bug 1300458)
+      const cmdShortcut = shortcut.meta && !shortcut.alt && !shortcut.ctrl;
+      if (isAlphabetical || cmdShortcut) {
+        return false;
+      }
+    }
+
+    if (shortcut.keyCode) {
+      return event.keyCode == shortcut.keyCode;
+    } else if (event.key in ElectronKeysMapping) {
+      return ElectronKeysMapping[event.key] === shortcut.key;
+    }
+
+    // get the key from the keyCode if key is not provided.
+    const key = event.key || String.fromCharCode(event.keyCode);
+
+    // For character keys, we match if the final character is the expected one.
+    // But for digits we also accept indirect match to please azerty keyboard,
+    // which requires Shift to be pressed to get digits.
+    return (
+      key.toLowerCase() == shortcut.key ||
+      (shortcut.key.match(/[0-9]/) &&
+        event.keyCode == shortcut.key.charCodeAt(0))
+    );
+  },
+
+  handleEvent(event) {
+    for (const [key, shortcut] of this.keys) {
+      if (this.doesEventMatchShortcut(event, shortcut)) {
+        this.eventEmitter.emit(key, event);
+      }
+    }
+  },
+
+  on(key, listener) {
+    if (typeof listener !== "function") {
+      throw new Error(
+        "KeyShortcuts.on() expects a function as " + "second argument"
+      );
+    }
+    if (!this.keys.has(key)) {
+      const shortcut = KeyShortcuts.parseElectronKey(this.window, key);
+      // The key string is wrong and we were unable to compute the key shortcut
+      if (!shortcut) {
+        return;
+      }
+      this.keys.set(key, shortcut);
+    }
+    this.eventEmitter.on(key, listener);
+  },
+
+  off(key, listener) {
+    this.eventEmitter.off(key, listener);
+  },
+};
+
+module.exports = KeyShortcuts;