Do PPB_FileIO Query and Read in the plugin process.

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>
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
 
 #if defined(OS_ANDROID)
 #include "base/os_compat_android.h"
 #endif
 
 namespace base {
 
 // Make sure our Whence mappings match the system headers.
 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();
   return fstat(fd, sb);
 }
 #else
 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));
+}
+
+static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
+#ifdef __USE_XOPEN2K8
+  // futimens should be available, but futimes might not be
+  // http://pubs.opengroup.org/onlinepubs/9699919799/
+
+  timespec ts_times[2];
+  ts_times[0].tv_sec  = times[0].tv_sec;
+  ts_times[0].tv_nsec = times[0].tv_usec * 1000;
+  ts_times[1].tv_sec  = times[1].tv_sec;
+  ts_times[1].tv_nsec = times[1].tv_usec * 1000;
+
+  return futimens(file, ts_times);
+#else
+  return futimes(file, times);
+#endif
+}
+#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.
+  return 0;
+}
+
+static int CallFsync(PlatformFile file) {
+  NOTIMPLEMENTED();  // NaCl doesn't implement fsync.
+  return 0;
+}
+
+static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
+  NOTIMPLEMENTED();  // NaCl doesn't implement futimes.
+  return 0;
+}
+#endif  // defined(OS_NACL)
+
+}  // namespace
+
+// NaCl doesn't implement system calls to open files directly.
+#if !defined(OS_NACL)
 // TODO(erikkay): does it make sense to support PLATFORM_FILE_EXCLUSIVE_* here?
 PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
                                       int flags,
                                       bool* created,
                                       PlatformFileError* error) {
   base::ThreadRestrictions::AssertIOAllowed();
 
   int open_flags = 0;
   if (flags & PLATFORM_FILE_CREATE)
     open_flags = O_CREAT | O_EXCL;
@@ skipping 78 matching lines @@
     else
       *error = ErrnoToPlatformFileError(errno);
   }
 
   return descriptor;
 }
 
 FILE* FdopenPlatformFile(PlatformFile file, const char* mode) {
   return fdopen(file, mode);
 }
+#endif  // !defined(OS_NACL)
 
 bool ClosePlatformFile(PlatformFile file) {
   base::ThreadRestrictions::AssertIOAllowed();
   return !HANDLE_EINTR(close(file));
 }
 
 int64 SeekPlatformFile(PlatformFile file,
                        PlatformFileWhence whence,
                        int64 offset) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (file < 0 || offset < 0)
     return -1;
 
   return lseek(file, static_cast<off_t>(offset), static_cast<int>(whence));
 }
 
 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 = HANDLE_EINTR(pread(file, data + bytes_read,
-                            size - bytes_read, offset + bytes_read));
+    rv = DoPread(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 HANDLE_EINTR(pread(file, data, size, offset));
+  return DoPread(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 (fcntl(file, F_GETFL) & O_APPEND)
+  if (IsOpenAppend(file))
     return WritePlatformFileAtCurrentPos(file, data, size);
 
   if (file < 0 || size < 0)
     return -1;
 
   int bytes_written = 0;
   int rv;
   do {
-    rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
-                             size - bytes_written, offset + bytes_written));
+    rv = DoPwrite(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 19 matching lines @@
                                         const char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (file < 0 || size < 0)
     return -1;
 
   return HANDLE_EINTR(write(file, data, size));
 }
 
 bool TruncatePlatformFile(PlatformFile file, int64 length) {
   base::ThreadRestrictions::AssertIOAllowed();
-  return ((file >= 0) && !HANDLE_EINTR(ftruncate(file, length)));
+  return ((file >= 0) && !CallFtruncate(file, length));
 }
 
 bool FlushPlatformFile(PlatformFile file) {
   base::ThreadRestrictions::AssertIOAllowed();
-  return !HANDLE_EINTR(fsync(file));
+  return !CallFsync(file);
 }
 
 bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
                        const base::Time& last_modified_time) {
   base::ThreadRestrictions::AssertIOAllowed();
   if (file < 0)
     return false;
 
   timeval times[2];
   times[0] = last_access_time.ToTimeVal();
   times[1] = last_modified_time.ToTimeVal();
 
-#ifdef __USE_XOPEN2K8
-  // futimens should be available, but futimes might not be
-  // http://pubs.opengroup.org/onlinepubs/9699919799/
-
-  timespec ts_times[2];
-  ts_times[0].tv_sec  = times[0].tv_sec;
-  ts_times[0].tv_nsec = times[0].tv_usec * 1000;
-  ts_times[1].tv_sec  = times[1].tv_sec;
-  ts_times[1].tv_nsec = times[1].tv_usec * 1000;
-
-  return !futimens(file, ts_times);
-#else
-  return !futimes(file, times);
-#endif
+  return !CallFutimes(file, times);
 }
 
 bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info) {
   if (!info)
     return false;
 
   stat_wrapper_t file_info;
   if (CallFstat(file, &file_info))
     return false;
 
   info->is_directory = S_ISDIR(file_info.st_mode);
   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
   info->size = file_info.st_size;
   info->last_modified = base::Time::FromTimeT(file_info.st_mtime);
   info->last_accessed = base::Time::FromTimeT(file_info.st_atime);
   info->creation_time = base::Time::FromTimeT(file_info.st_ctime);
   return true;
 }
 
 PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
   switch (saved_errno) {
     case EACCES:
     case EISDIR:
     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:
       return PLATFORM_FILE_ERROR_NOT_FOUND;
     case EMFILE:
       return PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
     case ENOMEM:
       return PLATFORM_FILE_ERROR_NO_MEMORY;
     case ENOSPC:
       return PLATFORM_FILE_ERROR_NO_SPACE;
     case ENOTDIR:
       return PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
     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