Port base/files/file_util_proxy to Native Client.

base/platform_file_posix.cc

Index: base/platform_file_posix.cc
diff --git a/base/platform_file_posix.cc b/base/platform_file_posix.cc
index 7e6335e88451a090c54a6370f75b5a0122a6b8b3..4d2012a67b5a3b8238d8845049b6effa73f8b99e 100644
--- a/base/platform_file_posix.cc
+++ b/base/platform_file_posix.cc
@@ -27,7 +27,9 @@ COMPILE_ASSERT(PLATFORM_FILE_FROM_BEGIN   == SEEK_SET &&
                PLATFORM_FILE_FROM_CURRENT == SEEK_CUR &&
                PLATFORM_FILE_FROM_END     == SEEK_END, whence_matches_system);
 
-#if defined(OS_BSD) || defined(OS_MACOSX)
+namespace {
+
+#if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)
 typedef struct stat stat_wrapper_t;
 static int CallFstat(int fd, stat_wrapper_t *sb) {
   base::ThreadRestrictions::AssertIOAllowed();
@@ -41,6 +43,32 @@ static int CallFstat(int fd, stat_wrapper_t *sb) {
 }
 #endif
 
+// TODO(bbudge) Remove NaCl workarounds when it implements pread and pwrite.
+#if !defined(OS_NACL)
+static int CallPread(PlatformFile file, char* data, int size, int64 offset) {
+  return HANDLE_EINTR(pread(file, data, size, offset));
+}
+static int CallPwrite(PlatformFile file, const char* data, int size,
+                      int64 offset) {
+  return HANDLE_EINTR(pwrite(file, data, size, offset));
+}
+#else
+static int CallPread(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 CallPwrite(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));
+}
+#endif
+
+}  // namespace
+
+// NaCl lacks many file handling system calls, so exclude any platform file
+// functions that can't be implemented there.
+#if !defined(OS_NACL)
 // TODO(erikkay): does it make sense to support PLATFORM_FILE_EXCLUSIVE_* here?
 PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
                                       int flags,
@@ -139,6 +167,7 @@ PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
 FILE* FdopenPlatformFile(PlatformFile file, const char* mode) {
   return fdopen(file, mode);
 }
+#endif  // !defined(OS_NACL)
 
 bool ClosePlatformFile(PlatformFile file) {
   base::ThreadRestrictions::AssertIOAllowed();
@@ -163,8 +192,8 @@ int ReadPlatformFile(PlatformFile file, int64 offset, char* data, int size) {
   int bytes_read = 0;
   int rv;
   do {
-    rv = HANDLE_EINTR(pread(file, data + bytes_read,
-                            size - bytes_read, offset + bytes_read));
+    rv = CallPread(file, data + bytes_read,
+                   size - bytes_read, offset + bytes_read);
     if (rv <= 0)
       break;
 
@@ -198,7 +227,7 @@ int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
   if (file < 0)
     return -1;
 
-  return HANDLE_EINTR(pread(file, data, size, offset));
+  return CallPread(file, data, size, offset);
 }
 
 int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
@@ -214,8 +243,10 @@ int WritePlatformFile(PlatformFile file, int64 offset,
                       const char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
 
+#if !defined(OS_NACL)  // NaCl has no fcntl, but it shouldn't be needed here.
   if (fcntl(file, F_GETFL) & O_APPEND)
     return WritePlatformFileAtCurrentPos(file, data, size);
+#endif  // !defined(OS_NACL)
 
   if (file < 0 || size < 0)
     return -1;
@@ -223,8 +254,8 @@ int WritePlatformFile(PlatformFile file, int64 offset,
   int bytes_written = 0;
   int rv;
   do {
-    rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
-                             size - bytes_written, offset + bytes_written));
+    rv = CallPwrite(file, data + bytes_written,
+                    size - bytes_written, offset + bytes_written);
     if (rv <= 0)
       break;
 
@@ -262,6 +293,7 @@ int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
   return HANDLE_EINTR(write(file, data, size));
 }
 
+#if !defined(OS_NACL)  // NaCl has no ftruncate or fsync.
 bool TruncatePlatformFile(PlatformFile file, int64 length) {
   base::ThreadRestrictions::AssertIOAllowed();
   return ((file >= 0) && !HANDLE_EINTR(ftruncate(file, length)));
@@ -271,7 +303,9 @@ bool FlushPlatformFile(PlatformFile file) {
   base::ThreadRestrictions::AssertIOAllowed();
   return !HANDLE_EINTR(fsync(file));
 }
+#endif  // !defined(OS_NACL)
 
+#if !defined(OS_NACL)
 bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
                        const base::Time& last_modified_time) {
   base::ThreadRestrictions::AssertIOAllowed();
@@ -297,6 +331,7 @@ bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
   return !futimes(file, times);
 #endif
 }
+#endif  // !defined(OS_NACL)
 
 bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info) {
   if (!info)
@@ -322,8 +357,10 @@ PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
     case EROFS:
     case EPERM:
       return PLATFORM_FILE_ERROR_ACCESS_DENIED;
+#if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
     case ETXTBSY:
       return PLATFORM_FILE_ERROR_IN_USE;
+#endif
     case EEXIST:
       return PLATFORM_FILE_ERROR_EXISTS;
     case ENOENT: