Make Platform.executable return the fully qualified path of the execu…

…table

BUG=http://dartbug.com/16994
R=kustermann@google.com, lrn@google.com

Review URL: https://codereview.chromium.org//1145053002

runtime/bin/platform.cc

@@ -13,6 +13,7 @@ namespace dart {
 namespace bin {
 
 const char* Platform::executable_name_ = NULL;
+bool Platform::executable_name_resolved_ = false;
 const char* Platform::package_root_ = NULL;
 int Platform::script_index_ = 1;
 char** Platform::argv_ = NULL;

runtime/bin/platform.h

@@ -39,11 +39,21 @@ class Platform {
   static char** Environment(intptr_t* count);
   static void FreeEnvironment(char** env, intptr_t count);
 
-  // Stores and gets the executable name.
+  static char* ResolveExecutablePath();
+
+  // Stores the executable name.
   static void SetExecutableName(const char* executable_name) {
     executable_name_ = executable_name;
   }
   static const char* GetExecutableName() {
+    if (!executable_name_resolved_) {
+      // Try to resolve the executable path using platform specific APIs.
+      char* path = Platform::ResolveExecutablePath();
+      if (path != NULL) {
+        executable_name_ = path;
+      }
+      executable_name_resolved_ = true;
+    }
     return executable_name_;
   }
 
@@ -68,7 +78,11 @@ class Platform {
   }
 
  private:
+  // The path to the executable.
   static const char* executable_name_;
+  // State to indicate whether the executable name has been resolved.
+  static bool executable_name_resolved_;
+
   static const char* package_root_;
   static int script_index_;
   static char** argv_;  // VM flags are argv_[1 ... script_index_ - 1]

runtime/bin/platform_android.cc

@@ -71,6 +71,11 @@ void Platform::FreeEnvironment(char** env, intptr_t count) {
   delete[] env;
 }
 
+
+char* Platform::ResolveExecutablePath() {
+  return File::LinkTarget("/proc/self/exe");
+}
+
 }  // namespace bin
 }  // namespace dart
 

runtime/bin/platform_linux.cc

@@ -5,6 +5,7 @@
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
+#include "bin/file.h"
 #include "bin/platform.h"
 
 #include <signal.h>  // NOLINT
@@ -71,6 +72,11 @@ void Platform::FreeEnvironment(char** env, intptr_t count) {
   delete[] env;
 }
 
+
+char* Platform::ResolveExecutablePath() {
+  return File::LinkTarget("/proc/self/exe");
+}
+
 }  // namespace bin
 }  // namespace dart
 

runtime/bin/platform_macos.cc

@@ -5,6 +5,8 @@
 #include "platform/globals.h"
 #if defined(TARGET_OS_MACOS)
 
+#include <mach-o/dyld.h>
+
 #include "bin/platform.h"
 
 #include <crt_externs.h>  // NOLINT
@@ -75,6 +77,23 @@ void Platform::FreeEnvironment(char** env, intptr_t count) {
   delete[] env;
 }
 
+
+char* Platform::ResolveExecutablePath() {
+  // Get the required length of the buffer.
+  uint32_t path_size = 0;
+  char* path = NULL;
+  if (_NSGetExecutablePath(path, &path_size) == 0) {
+    return NULL;
+  }
+  // Allocate buffer and get executable path.
+  path = reinterpret_cast<char*>(malloc(path_size));
+  if (_NSGetExecutablePath(path, &path_size) != 0) {
+    free(path);
+    return NULL;
+  }
+  return path;
+}
+
 }  // namespace bin
 }  // namespace dart
 

runtime/bin/platform_win.cc

@@ -80,6 +80,26 @@ void Platform::FreeEnvironment(char** env, intptr_t count) {
   delete[] env;
 }
 
+
+char* Platform::ResolveExecutablePath() {
+  // GetModuleFileNameW cannot directly provide information on the
+  // required buffer size, so start out with a buffer large enough to
+  // hold any Windows path.
+  const int kTmpBufferSize = 32768;
+  wchar_t* tmp_buffer = reinterpret_cast<wchar_t*>(malloc(kTmpBufferSize));
+  // Ensure no last error before calling GetModuleFileNameW.
+  SetLastError(ERROR_SUCCESS);
+  // Get the required length of the buffer.
+  int path_length = GetModuleFileNameW(NULL, tmp_buffer, kTmpBufferSize);
+  if (GetLastError() != ERROR_SUCCESS) {
+    free(tmp_buffer);
+    return NULL;
+  }
+  char* path = StringUtils::WideToUtf8(tmp_buffer);
+  free(tmp_buffer);
+  return path;
+}
+
 }  // namespace bin
 }  // namespace dart
 

sdk/lib/io/platform.dart

@@ -39,7 +39,7 @@ part of dart.io;
  *       Map<String, String> envVars = Platform.environment;
  *       print(envVars['PATH']);
  *     }
- * 
+ *
  * ## Determine the OS
  *
  * You can get the name of the operating system as a string with the
@@ -53,7 +53,7 @@ part of dart.io;
  *       String os = Platform.operatingSystem;
  *       // Or, use a predicate getter.
  *       if (Platform.isMacOS) {
- *         Print('is a Mac'); 
+ *         Print('is a Mac');
  *       } else {
  *        print('is not a Mac');
  *       }
@@ -62,7 +62,7 @@ part of dart.io;
  * ## Other resources
  *
  * [Dart by Example](https://www.dartlang.org/dart-by-example/#dart-io-and-command-line-apps)
- * provides additional task-oriented code samples that show how to use 
+ * provides additional task-oriented code samples that show how to use
  * various API from the [dart:io] library.
  */
 class Platform {
@@ -131,6 +131,8 @@ class Platform {
    * Returns the path of the executable used to run the script in this
    * isolate.
    *
+   * If supported by the platform the returned path will be absolute.
+   *
    * If the execution environment does not support [executable] an empty
    * string is returned.
    */

tests/standalone/io/platform_test.dart

@@ -25,6 +25,15 @@ test() {
   var environment = Platform.environment;
   Expect.isTrue(environment is Map<String, String>);
   Expect.isTrue(Platform.executable.contains('dart'));
+  if (!Platform.isWindows) {
+    Expect.isTrue(Platform.executable.startsWith('/'));
+  } else {
+    // This assumes that tests (both locally and on the bots) are
+    // running off a location referred to by a drive letter. If a UNC
+    // location is used or long names ("\\?\" prefix) is used this
+    // needs to be fixed.
+    Expect.equals(Platform.executable.substring(1, 3), ':\\');
+  }
   // Move directory to be sure script is correct.
   var oldDir = Directory.current;
   Directory.current = Directory.current.parent;