1 files changed, 91 insertions, 0 deletions
diff --git a/mobile/android/modules/geckoview/AndroidLog.jsm b/mobile/android/modules/geckoview/AndroidLog.jsm
new file mode 100644
index 0000000000..cbc7087da4
--- /dev/null
+++ b/mobile/android/modules/geckoview/AndroidLog.jsm
@@ -0,0 +1,91 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * 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";
+
+/**
+ * Native Android logging for JavaScript.  Lets you specify a priority and tag
+ * in addition to the message being logged.  Resembles the android.util.Log API
+ * <http://developer.android.com/reference/android/util/Log.html>.
+ *
+ * // Import it as a JSM:
+ * let Log = ChromeUtils.import("resource://gre/modules/AndroidLog.jsm")
+ *   .AndroidLog;
+ *
+ * // Use Log.i, Log.v, Log.d, Log.w, and Log.e to log verbose, debug, info,
+ * // warning, and error messages, respectively.
+ * Log.v("MyModule", "This is a verbose message.");
+ * Log.d("MyModule", "This is a debug message.");
+ * Log.i("MyModule", "This is an info message.");
+ * Log.w("MyModule", "This is a warning message.");
+ * Log.e("MyModule", "This is an error message.");
+ *
+ * // Bind a function with a tag to replace a bespoke dump/log/debug function:
+ * let debug = Log.d.bind(null, "MyModule");
+ * debug("This is a debug message.");
+ * // Outputs "D/GeckoMyModule(#####): This is a debug message."
+ *
+ * // Or "bind" the module object to a tag to automatically tag messages:
+ * Log = Log.bind("MyModule");
+ * Log.d("This is a debug message.");
+ * // Outputs "D/GeckoMyModule(#####): This is a debug message."
+ *
+ * Note: the module automatically prepends "Gecko" to the tag you specify,
+ * since all tags used by Fennec code should start with that string; and it
+ * truncates tags longer than MAX_TAG_LENGTH characters (not including "Gecko").
+ */
+
+const EXPORTED_SYMBOLS = ["AndroidLog"];
+const { ctypes } = ChromeUtils.importESModule(
+  "resource://gre/modules/ctypes.sys.mjs"
+);
+
+// From <https://android.googlesource.com/platform/system/core/+/master/include/android/log.h>.
+const ANDROID_LOG_VERBOSE = 2;
+const ANDROID_LOG_DEBUG = 3;
+const ANDROID_LOG_INFO = 4;
+const ANDROID_LOG_WARN = 5;
+const ANDROID_LOG_ERROR = 6;
+
+// android.util.Log.isLoggable throws IllegalArgumentException if a tag length
+// exceeds 23 characters, and we prepend five characters ("Gecko") to every tag.
+// However, __android_log_write itself and other android.util.Log methods don't
+// seem to mind longer tags.
+const MAX_TAG_LENGTH = 18;
+
+var liblog = ctypes.open("liblog.so"); // /system/lib/liblog.so
+var __android_log_write = liblog.declare(
+  "__android_log_write",
+  ctypes.default_abi,
+  ctypes.int, // return value: num bytes logged
+  ctypes.int, // priority (ANDROID_LOG_* constant)
+  ctypes.char.ptr, // tag
+  ctypes.char.ptr
+); // message
+
+var AndroidLog = {
+  MAX_TAG_LENGTH,
+  v: (tag, msg) => __android_log_write(ANDROID_LOG_VERBOSE, "Gecko" + tag, msg),
+  d: (tag, msg) => __android_log_write(ANDROID_LOG_DEBUG, "Gecko" + tag, msg),
+  i: (tag, msg) => __android_log_write(ANDROID_LOG_INFO, "Gecko" + tag, msg),
+  w: (tag, msg) => __android_log_write(ANDROID_LOG_WARN, "Gecko" + tag, msg),
+  e: (tag, msg) => __android_log_write(ANDROID_LOG_ERROR, "Gecko" + tag, msg),
+
+  bind(tag) {
+    return {
+      MAX_TAG_LENGTH,
+      v: AndroidLog.v.bind(null, tag),
+      d: AndroidLog.d.bind(null, tag),
+      i: AndroidLog.i.bind(null, tag),
+      w: AndroidLog.w.bind(null, tag),
+      e: AndroidLog.e.bind(null, tag),
+    };
+  },
+};
+
+if (typeof Components == "undefined") {
+  // Specify exported symbols for require.js module loader.
+  // eslint-disable-next-line no-undef
+  module.exports = AndroidLog;
+}