Fix net::FileStream to handle POSIX errors correctly.

net/base/file_stream_context_posix.cc

Index: net/base/file_stream_context_posix.cc
diff --git a/net/base/file_stream_context_posix.cc b/net/base/file_stream_context_posix.cc
index 0c16ef4160bee5a8a73991ee72574bf384cfe40d..1bc1640c4bd5faa3ca353d8998dfcaf1762c7c68 100644
--- a/net/base/file_stream_context_posix.cc
+++ b/net/base/file_stream_context_posix.cc
@@ -68,8 +68,11 @@ FileStream::Context::~Context() {
 
 int64 FileStream::Context::GetFileSize() const {
   struct stat info;
-  if (fstat(file_, &info) != 0)
-    return RecordAndMapError(errno, FILE_ERROR_SOURCE_GET_SIZE);
+  if (fstat(file_, &info) != 0) {
+    IOResult result = IOResult::FromOSError(errno);
+    RecordError(result, FILE_ERROR_SOURCE_GET_SIZE);
+    return result.result;
+  }
 
   return static_cast<int64>(info.st_size);
 }
@@ -96,9 +99,9 @@ int FileStream::Context::ReadAsync(IOBuffer* in_buf,
 
 int FileStream::Context::ReadSync(char* in_buf, int buf_len) {
   scoped_refptr<IOBuffer> buf = new WrappedIOBuffer(in_buf);
-  int64 result = ReadFileImpl(buf, buf_len);
-  CheckForIOError(&result, FILE_ERROR_SOURCE_READ);
-  return result;
+  IOResult result = ReadFileImpl(buf, buf_len);
+  RecordError(result, FILE_ERROR_SOURCE_READ);
+  return result.result;
 }
 
 int FileStream::Context::WriteAsync(IOBuffer* in_buf,
@@ -123,54 +126,59 @@ int FileStream::Context::WriteAsync(IOBuffer* in_buf,
 
 int FileStream::Context::WriteSync(const char* in_buf, int buf_len) {
   scoped_refptr<IOBuffer> buf = new WrappedIOBuffer(in_buf);
-  int64 result = WriteFileImpl(buf, buf_len);
-  CheckForIOError(&result, FILE_ERROR_SOURCE_WRITE);
-  return result;
+  IOResult result = WriteFileImpl(buf, buf_len);
+  RecordError(result, FILE_ERROR_SOURCE_WRITE);
+  return result.result;
 }
 
 int FileStream::Context::Truncate(int64 bytes) {
-  int result = ftruncate(file_, bytes);
-  if (result == 0)
-    return bytes;
+  if (ftruncate(file_, bytes) != 0) {
+    IOResult result = IOResult::FromOSError(errno);
+    RecordError(result, FILE_ERROR_SOURCE_SET_EOF);
+    return result.result;
+  }
 
-  return RecordAndMapError(errno, FILE_ERROR_SOURCE_SET_EOF);
+  return bytes;
 }
 
-int64 FileStream::Context::SeekFileImpl(Whence whence, int64 offset) {
+FileStream::Context::IOResult FileStream::Context::SeekFileImpl(Whence whence,
+                                                                int64 offset) {
   off_t res = lseek(file_, static_cast<off_t>(offset),
                     static_cast<int>(whence));
   if (res == static_cast<off_t>(-1))
-    return errno;
+    return IOResult::FromOSError(errno);
 
-  return res;
+  return IOResult(res, 0);
 }
 
-int64 FileStream::Context::FlushFileImpl() {
+FileStream::Context::IOResult FileStream::Context::FlushFileImpl() {
   ssize_t res = HANDLE_EINTR(fsync(file_));
   if (res == -1)
-    return errno;
+    return IOResult::FromOSError(errno);
 
-  return res;
+  return IOResult(res, 0);
 }
 
-int64 FileStream::Context::ReadFileImpl(scoped_refptr<IOBuffer> buf,
-                                        int buf_len) {
+FileStream::Context::IOResult FileStream::Context::ReadFileImpl(
+    scoped_refptr<IOBuffer> buf,
+    int buf_len) {
   // Loop in the case of getting interrupted by a signal.
   ssize_t res = HANDLE_EINTR(read(file_, buf->data(),
                                   static_cast<size_t>(buf_len)));
   if (res == -1)
-    return errno;
+    return IOResult::FromOSError(errno);
 
-  return res;
+  return IOResult(res, 0);
 }
 
-int64 FileStream::Context::WriteFileImpl(scoped_refptr<IOBuffer> buf,
-                                         int buf_len) {
+FileStream::Context::IOResult FileStream::Context::WriteFileImpl(
+    scoped_refptr<IOBuffer> buf,
+    int buf_len) {
   ssize_t res = HANDLE_EINTR(write(file_, buf->data(), buf_len));
   if (res == -1)
-    return errno;
+    return IOResult::FromOSError(errno);
 
-  return res;
+  return IOResult(res, 0);
 }
 
 }  // namespace net