Add fml::paths::GetExecutableDirectoryPath. (flutter/engine#3508)

engine/src/flutter/fml/BUILD.gn

@@ -12,6 +12,7 @@ source_set("fml") {
     "message_loop.h",
     "message_loop_impl.cc",
     "message_loop_impl.h",
+    "paths.h",
     "task_runner.cc",
     "task_runner.h",
     "thread.cc",
@@ -43,6 +44,7 @@ source_set("fml") {
       "platform/darwin/message_loop_darwin.mm",
       "platform/darwin/nsstring_utils.h",
       "platform/darwin/nsstring_utils.mm",
+      "platform/darwin/paths_darwin.mm",
       "platform/darwin/resource_mapping_darwin.h",
       "platform/darwin/resource_mapping_darwin.mm",
       "platform/darwin/scoped_block.h",
@@ -62,6 +64,7 @@ source_set("fml") {
       "platform/android/jni_weak_ref.h",
       "platform/android/message_loop_android.cc",
       "platform/android/message_loop_android.h",
+      "platform/android/paths_android.cc",
       "platform/android/scoped_java_ref.cc",
       "platform/android/scoped_java_ref.h",
     ]
@@ -83,6 +86,7 @@ source_set("fml") {
     sources += [
       "platform/linux/message_loop_linux.cc",
       "platform/linux/message_loop_linux.h",
+      "platform/linux/paths_linux.cc",
       "platform/linux/timerfd.cc",
       "platform/linux/timerfd.h",
     ]

engine/src/flutter/fml/icu_util.cc

@@ -8,6 +8,7 @@
 #include <mutex>
 
 #include "flutter/fml/mapping.h"
+#include "flutter/fml/paths.h"
 #include "lib/ftl/build_config.h"
 #include "lib/ftl/logging.h"
 #include "third_party/icu/source/common/unicode/udata.h"
@@ -44,7 +45,16 @@ class ICUContext {
 
     // Check if the mapping can by directly accessed via a file path. In this
     // case, the data file needs to be next to the executable.
-    auto file = std::make_unique<FileMapping>(kIcuDataFileName);
+    auto directory = fml::paths::GetExecutableDirectoryPath();
+
+    if (!directory.first) {
+      return false;
+    }
+
+    // FIXME(chinmaygarde): There is no Path::Join in FTL. So a non-portable
+    // version is used here. Patch FTL and update.
+    auto file = std::make_unique<FileMapping>(directory.second + "/" +
+                                              kIcuDataFileName);
     if (file->GetSize() != 0) {
       mapping_ = std::move(file);
       return true;

engine/src/flutter/fml/paths.h

@@ -0,0 +1,19 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_FML_PATHS_H_
+#define FLUTTER_FML_PATHS_H_
+
+#include <string>
+#include <utility>
+
+namespace fml {
+namespace paths {
+
+std::pair<bool, std::string> GetExecutableDirectoryPath();
+
+}  // namespace paths
+}  // namespace fml
+
+#endif  // FLUTTER_FML_PATHS_H_

engine/src/flutter/fml/platform/android/paths_android.cc

@@ -0,0 +1,15 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/fml/paths.h"
+
+namespace fml {
+namespace paths {
+
+std::pair<bool, std::string> GetExecutableDirectoryPath() {
+  return {false, ""};
+}
+
+}  // namespace paths
+}  // namespace fml

engine/src/flutter/fml/platform/darwin/paths_darwin.mm

@@ -0,0 +1,20 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/fml/paths.h"
+
+#include <Foundation/Foundation.h>
+
+#include "lib/ftl/files/path.h"
+
+namespace fml {
+namespace paths {
+
+std::pair<bool, std::string> GetExecutableDirectoryPath() {
+  return {true, files::GetDirectoryName(
+                    [NSBundle mainBundle].executablePath.UTF8String)};
+}
+
+}  // namespace paths
+}  // namespace fml

engine/src/flutter/fml/platform/linux/paths_linux.cc

@@ -0,0 +1,25 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/fml/paths.h"
+
+#include <unistd.h>
+
+#include "lib/ftl/files/path.h"
+
+namespace fml {
+namespace paths {
+
+std::pair<bool, std::string> GetExecutableDirectoryPath() {
+  const int path_size = 255;
+  char path[path_size] = {0};
+  auto read_size = ::readlink("/proc/self/exe", path, path_size);
+  if (read_size == -1) {
+    return {false, ""};
+  }
+  return {true, files::GetDirectoryName(std::string{path, read_size})};
+}
+
+}  // namespace paths
+}  // namespace fml