Use pread and pwrite in NaCl PlatformFile now that they're available.

base/platform_file_posix.cc

 // Copyright (c) 2012 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 "base/platform_file.h"
 
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 28 matching lines @@
 typedef struct stat64 stat_wrapper_t;
 static int CallFstat(int fd, stat_wrapper_t *sb) {
   base::ThreadRestrictions::AssertIOAllowed();
   return fstat64(fd, sb);
 }
 #endif
 
 // NaCl doesn't provide the following system calls, so either simulate them or
 // wrap them in order to minimize the number of #ifdef's in this file.
 #if !defined(OS_NACL)
-static int DoPread(PlatformFile file, char* data, int size, int64 offset) {
-  return HANDLE_EINTR(pread(file, data, size, offset));
-}
-
-static int DoPwrite(PlatformFile file, const char* data, int size,
-                      int64 offset) {
-  return HANDLE_EINTR(pwrite(file, data, size, offset));
-}
-
 static bool IsOpenAppend(PlatformFile file) {
   return (fcntl(file, F_GETFL) & O_APPEND) != 0;
 }
 
 static int CallFtruncate(PlatformFile file, int64 length) {
   return HANDLE_EINTR(ftruncate(file, length));
 }
 
 static int CallFsync(PlatformFile file) {
   return HANDLE_EINTR(fsync(file));
@@ skipping 20 matching lines @@
   struct flock lock;
   lock.l_type = F_WRLCK;
   lock.l_whence = SEEK_SET;
   lock.l_start = 0;
   lock.l_len = 0;  // Lock entire file.
   if (HANDLE_EINTR(fcntl(file, do_lock ? F_SETLK : F_UNLCK, &lock)) == -1)
     return ErrnoToPlatformFileError(errno);
   return PLATFORM_FILE_OK;
 }
 #else  // defined(OS_NACL)
-// TODO(bbudge) Remove DoPread, DoPwrite when NaCl implements pread, pwrite.
-static int DoPread(PlatformFile file, char* data, int size, int64 offset) {
-  lseek(file, static_cast<off_t>(offset), SEEK_SET);
-  return HANDLE_EINTR(read(file, data, size));
-}
-
-static int DoPwrite(PlatformFile file, const char* data, int size,
-                      int64 offset) {
-  lseek(file, static_cast<off_t>(offset), SEEK_SET);
-  return HANDLE_EINTR(write(file, data, size));
-}
 
 static bool IsOpenAppend(PlatformFile file) {
   // NaCl doesn't implement fcntl. Since NaCl's write conforms to the POSIX
   // standard and always appends if the file is opened with O_APPEND, just
   // return false here.
   return false;
 }
 
 static int CallFtruncate(PlatformFile file, int64 length) {
   NOTIMPLEMENTED();  // NaCl doesn't implement ftruncate.
@@ skipping 136 matching lines @@
 }
 
 int ReadPlatformFile(PlatformFile file, int64 offset, char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (file < 0 || size < 0)
     return -1;
 
   int bytes_read = 0;
   int rv;
   do {
-    rv = DoPread(file, data + bytes_read,
-                 size - bytes_read, offset + bytes_read);
+    rv = HANDLE_EINTR(pread(file, data + bytes_read,
+                            size - bytes_read, offset + bytes_read));
     if (rv <= 0)
       break;
 
     bytes_read += rv;
   } while (bytes_read < size);
 
   return bytes_read ? bytes_read : rv;
 }
 
 int ReadPlatformFileAtCurrentPos(PlatformFile file, char* data, int size) {
@@ skipping 13 matching lines @@
 
   return bytes_read ? bytes_read : rv;
 }
 
 int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
                                  char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (file < 0)
     return -1;
 
-  return DoPread(file, data, size, offset);
+  return HANDLE_EINTR(pread(file, data, size, offset));
 }
 
 int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
                                        char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (file < 0 || size < 0)
     return -1;
 
   return HANDLE_EINTR(read(file, data, size));
 }
 
 int WritePlatformFile(PlatformFile file, int64 offset,
                       const char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
 
   if (IsOpenAppend(file))
     return WritePlatformFileAtCurrentPos(file, data, size);
 
   if (file < 0 || size < 0)
     return -1;
 
   int bytes_written = 0;
   int rv;
   do {
-    rv = DoPwrite(file, data + bytes_written,
-                  size - bytes_written, offset + bytes_written);
+    rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
+                             size - bytes_written, offset + bytes_written));
     if (rv <= 0)
       break;
 
     bytes_written += rv;
   } while (bytes_written < size);
 
   return bytes_written ? bytes_written : rv;
 }
 
 int WritePlatformFileAtCurrentPos(PlatformFile file,
@@ skipping 139 matching lines @@
     default:
 #if !defined(OS_NACL)  // NaCl build has no metrics code.
       UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Posix",
                                   saved_errno);
 #endif
       return PLATFORM_FILE_ERROR_FAILED;
   }
 }
 
 }  // namespace base