Improve the encoding/decoding to/from system encoding on Windows

runtime/bin/utils_android.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_ANDROID)
 
 #include <errno.h>  // NOLINT
 #include <netdb.h>  // NOLINT
 #include <sys/time.h>  // NOLINT
@@ skipping 24 matching lines @@
     char error_message[kBufferSize];
     strerror_r(code, error_message, kBufferSize);
     SetMessage(error_message);
   } else if (sub_system == kGetAddressInfo) {
     SetMessage(gai_strerror(code));
   } else {
     UNREACHABLE();
   }
 }
 
-const char* StringUtils::ConsoleStringToUtf8(const char* str) {
+const char* StringUtils::ConsoleStringToUtf8(
+    const char* str, intptr_t len, intptr_t* result_len) {
+  if (result_len != NULL) {
+    *result_len = len;
+  }
   return str;
 }
 
-const char* StringUtils::Utf8ToConsoleString(const char* utf8) {
+const char* StringUtils::Utf8ToConsoleString(
+    const char* utf8, intptr_t len, intptr_t* result_len) {
+  if (result_len != NULL) {
+    *result_len = len;
+  }
   return utf8;
 }
 
-char* StringUtils::ConsoleStringToUtf8(char* str) {
+char* StringUtils::ConsoleStringToUtf8(
+    char* str, intptr_t len, intptr_t* result_len) {
+  if (result_len != NULL) {
+    *result_len = len;
+  }
   return str;
 }
 
-char* StringUtils::Utf8ToConsoleString(char* utf8) {
+char* StringUtils::Utf8ToConsoleString(
+    char* utf8, intptr_t len, intptr_t* result_len) {
+  if (result_len != NULL) {
+    *result_len = len;
+  }
   return utf8;

[kustermann, 2015/06/22 11:11:21]

There is potential for issues here. Previously the assumption was that
conversion is 0-terminated. Which means we can just return the (hopefully
already 0-terminated) input.

Now if len is not the length of the input string, but rather shorter, we still
return the same string. This seems inconsistent with the windows implementation,
which would make a copy and 0-terminate the shorter string.

tl;dr Do we need to make a shorter 0-terminated copy iff "strlen(utf8) != len" ?

[Søren Gjesse, 2015/06/23 11:17:59]

Changed this to be only implemented on Windows. This code path is *never*
reached on other platforms, so I don't want to reason about what to do there.

 }
 
-wchar_t* StringUtils::Utf8ToWide(char* utf8) {
+wchar_t* StringUtils::Utf8ToWide(
+    char* utf8, intptr_t len, intptr_t* result_len) {
   UNIMPLEMENTED();
   return NULL;
 }
 
-const wchar_t* StringUtils::Utf8ToWide(const char* utf8) {
+const wchar_t* StringUtils::Utf8ToWide(
+    const char* utf8, intptr_t len, intptr_t* result_len) {
   UNIMPLEMENTED();
   return NULL;
 }
 
-char* StringUtils::WideToUtf8(wchar_t* str) {
+char* StringUtils::WideToUtf8(
+    wchar_t* str, intptr_t len, intptr_t* result_len) {
   UNIMPLEMENTED();
   return NULL;
 }
 
-const char* StringUtils::WideToUtf8(const wchar_t* str) {
+const char* StringUtils::WideToUtf8(
+    const wchar_t* str, intptr_t len, intptr_t* result_len) {
   UNIMPLEMENTED();
   return NULL;
 }
 
 wchar_t** ShellUtils::GetUnicodeArgv(int* argc) {
   return NULL;
 }
 
 void ShellUtils::FreeUnicodeArgv(wchar_t** argv) {
 }
@@ skipping 29 matching lines @@
     ASSERT(errno == EINTR);
     // Copy remainder into requested and repeat.
     req = rem;
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_ANDROID)