Bug 961665 - Native implementation of OS.File.read, js code. r=froydnj

toolkit/components/osfile/modules/moz.build

@@ -10,6 +10,7 @@ EXTRA_JS_MODULES += [
     '_PromiseWorker.jsm',
     'osfile_async_front.jsm',
     'osfile_async_worker.js',
+    'osfile_native.jsm',
     'osfile_shared_allthreads.jsm',
     'osfile_shared_front.jsm',
     'osfile_unix_allthreads.jsm',

toolkit/components/osfile/modules/osfile_async_front.jsm

@@ -58,6 +58,7 @@ Cu.import("resource://gre/modules/osfile/_PromiseWorker.jsm", this);
 Cu.import("resource://gre/modules/Services.jsm", this);
 Cu.import("resource://gre/modules/TelemetryStopwatch.jsm", this);
 Cu.import("resource://gre/modules/AsyncShutdown.jsm", this);
+let Native = Cu.import("resource://gre/modules/osfile/osfile_native.jsm", {});
 
 /**
  * Constructors for decoding standard exceptions
@@ -348,7 +349,7 @@ const PREF_OSFILE_LOG_REDIRECT = "toolkit.osfile.log.redirect";
  * @param bool oldPref
  *        An optional value that the DEBUG flag was set to previously.
  */
-let readDebugPref = function readDebugPref(prefName, oldPref = false) {
+function readDebugPref(prefName, oldPref = false) {
   let pref = oldPref;
   try {
     pref = Services.prefs.getBoolPref(prefName);
@@ -379,6 +380,19 @@ Services.prefs.addObserver(PREF_OSFILE_LOG_REDIRECT,
   }, false);
 SharedAll.Config.TEST = readDebugPref(PREF_OSFILE_LOG_REDIRECT, false);
 
+
+/**
+ * If |true|, use the native implementaiton of OS.File methods
+ * whenever possible. Otherwise, force the use of the JS version.
+ */
+let nativeWheneverAvailable = true;
+const PREF_OSFILE_NATIVE = "toolkit.osfile.native";
+Services.prefs.addObserver(PREF_OSFILE_NATIVE,
+  function prefObserver(aSubject, aTopic, aData) {
+    nativeWheneverAvailable = readDebugPref(PREF_OSFILE_NATIVE, nativeWheneverAvailable);
+  }, false);
+
+
 // Update worker's DEBUG flag if it's true.
 // Don't start the worker just for this, though.
 if (SharedAll.Config.DEBUG && Scheduler.launched) {
@@ -913,12 +927,32 @@ File.makeDir = function makeDir(path, options) {
  * read from the file.
  */
 File.read = function read(path, bytes, options = {}) {
+  if (typeof bytes == "object") {
+    // Passing |bytes| as an argument is deprecated.
+    // We should now be passing it as a field of |options|.
+    options = bytes || {};
+  } else {
+    options = clone(options, ["outExecutionDuration"]);
+    if (typeof bytes != "undefined") {
+      options.bytes = bytes;
+    }
+  }
+
+  if (options.compression || !nativeWheneverAvailable) {
+    // We need to use the JS implementation.
     let promise = Scheduler.post("read",
       [Type.path.toMsg(path), bytes, options], path);
     return promise.then(
       function onSuccess(data) {
+        if (typeof data == "string") {
+          return data;
+        }
         return new Uint8Array(data.buffer, data.byteOffset, data.byteLength);
       });
+  }
+
+  // Otherwise, use the native implementation.
+  return Scheduler.push(() => Native.read(path, options));
 };
 
 /**

toolkit/components/osfile/modules/osfile_async_worker.js

@@ -362,6 +362,9 @@ const EXCEPTION_NAMES = {
    },
    read: function read(path, bytes, options) {
      let data = File.read(Type.path.fromMsg(path), bytes, options);
+     if (typeof data == "string") {
+       return data;
+     }
      return new Meta({
          buffer: data.buffer,
          byteOffset: data.byteOffset,

toolkit/components/osfile/modules/osfile_native.jsm

@@ -0,0 +1,70 @@
+/* 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/. */
+
+/**
+ * Native (xpcom) implementation of key OS.File functions
+ */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["read"];
+
+let {results: Cr, utils: Cu, interfaces: Ci} = Components;
+
+let SharedAll = Cu.import("resource://gre/modules/osfile/osfile_shared_allthreads.jsm", {});
+
+let SysAll = {};
+if (SharedAll.Constants.Win) {
+  Cu.import("resource://gre/modules/osfile/osfile_win_allthreads.jsm", SysAll);
+} else if (SharedAll.Constants.libc) {
+  Cu.import("resource://gre/modules/osfile/osfile_unix_allthreads.jsm", SysAll);
+} else {
+  throw new Error("I am neither under Windows nor under a Posix system");
+}
+let {Promise} = Cu.import("resource://gre/modules/Promise.jsm", {});
+let {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
+
+/**
+ * The native service holding the implementation of the functions.
+ */
+XPCOMUtils.defineLazyServiceGetter(this,
+  "Internals",
+  "@mozilla.org/toolkit/osfile/native-internals;1",
+  "nsINativeOSFileInternalsService");
+
+/**
+ * Native implementation of OS.File.read
+ *
+ * This implementation does not handle option |compression|.
+ */
+this.read = function(path, options = {}) {
+  // Sanity check on types of options
+  if ("encoding" in options && typeof options.encoding != "string") {
+    return Promise.reject(new TypeError("Invalid type for option encoding"));
+  }
+  if ("compression" in options && typeof options.compression != "string") {
+    return Promise.reject(new TypeError("Invalid type for option compression"));
+  }
+  if ("bytes" in options && typeof options.bytes != "number") {
+    return Promise.reject(new TypeError("Invalid type for option bytes"));
+  }
+
+  let deferred = Promise.defer();
+  Internals.read(path,
+    options,
+    function onSuccess(success) {
+      success.QueryInterface(Ci.nsINativeOSFileResult);
+      if ("outExecutionDuration" in options) {
+        options.outExecutionDuration =
+          success.executionDurationMS +
+          (options.outExecutionDuration || 0);
+      }
+      deferred.resolve(success.result);
+    },
+    function onError(operation, oserror) {
+      deferred.reject(new SysAll.Error(operation, oserror, path));
+    }
+  );
+  return deferred.promise;
+};

toolkit/components/osfile/modules/osfile_shared_front.jsm

@@ -331,14 +331,35 @@ AbstractFile.read = function read(path, bytes, options = {}) {
     options = bytes;
     bytes = options.bytes || null;
   }
+  if ("encoding" in options && typeof options.encoding != "string") {
+    throw new TypeError("Invalid type for option encoding");
+  }
+  if ("compression" in options && typeof options.compression != "string") {
+    throw new TypeError("Invalid type for option compression: " + options.compression);
+  }
+  if ("bytes" in options && typeof options.bytes != "number") {
+    throw new TypeError("Invalid type for option bytes");
+  }
   let file = exports.OS.File.open(path);
   try {
     let buffer = file.read(bytes, options);
-    if ("compression" in options && options.compression == "lz4") {
-      return Lz4.decompressFileContent(buffer, options);
+    if ("compression" in options) {
+      if (options.compression == "lz4") {
+        buffer = Lz4.decompressFileContent(buffer, options);
       } else {
+        throw OS.File.Error.invalidArgument("Compression");
+      }
+    }
+    if (!("encoding" in options)) {
       return buffer;
     }
+    let decoder;
+    try {
+      decoder = new TextDecoder(options.encoding);
+    } catch (ex if ex instanceof TypeError) {
+      throw OS.File.Error.invalidArgument("Decode");
+    }
+    return decoder.decode(buffer);
   } finally {
     file.close();
   }

toolkit/components/osfile/modules/osfile_unix_allthreads.jsm

@@ -139,6 +139,15 @@ Object.defineProperty(OSError.prototype, "becauseAccessDenied", {
     return this.unixErrno == Const.EACCES;
   }
 });
+/**
+ * |true| if the error was raised because some invalid argument was passed,
+ * |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseInvalidArgument", {
+  get: function becauseInvalidArgument() {
+    return this.unixErrno == Const.EINVAL;
+  }
+});
 
 /**
  * Serialize an instance of OSError to something that can be
@@ -331,6 +340,10 @@ OSError.noSuchFile = function noSuchFile(operation, path) {
   return new OSError(operation, Const.ENOENT, path);
 };
 
+OSError.invalidArgument = function invalidArgument(operation) {
+  return new OSError(operation, Const.EINVAL);
+};
+
 let EXPORTED_SYMBOLS = [
   "declareFFI",
   "libc",

toolkit/components/osfile/modules/osfile_win_allthreads.jsm

@@ -161,6 +161,15 @@ Object.defineProperty(OSError.prototype, "becauseAccessDenied", {
     return this.winLastError == Const.ERROR_ACCESS_DENIED;
   }
 });
+/**
+ * |true| if the error was raised because some invalid argument was passed,
+ * |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseInvalidArgument", {
+  get: function becauseInvalidArgument() {
+    return this.winLastError == Const.ERROR_NOT_SUPPORTED;
+  }
+});
 
 /**
  * Serialize an instance of OSError to something that can be
@@ -368,6 +377,10 @@ OSError.noSuchFile = function noSuchFile(operation, path) {
   return new OSError(operation, Const.ERROR_FILE_NOT_FOUND, path);
 };
 
+OSError.invalidArgument = function invalidArgument(operation) {
+  return new OSError(operation, Const.ERROR_NOT_SUPPORTED);
+};
+
 let EXPORTED_SYMBOLS = [
   "declareFFI",
   "libc",