Fuchsia: Adds File::Copy()

runtime/bin/file_fuchsia.cc

 // Copyright (c) 2016, 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_FUCHSIA)
 
 #include "bin/file.h"
 
 #include <errno.h>      // NOLINT
 #include <fcntl.h>      // NOLINT
 #include <libgen.h>     // NOLINT
 #include <sys/mman.h>   // NOLINT
 #include <sys/stat.h>   // NOLINT
 #include <sys/types.h>  // NOLINT
 #include <unistd.h>     // NOLINT
 
 #include "bin/builtin.h"
+#include "bin/fdutils.h"
 #include "bin/log.h"
 #include "platform/signal_blocker.h"
 #include "platform/utils.h"
 
 namespace dart {
 namespace bin {
 
 class FileHandle {
  public:
   explicit FileHandle(int fd) : fd_(fd) {}
@@ skipping 244 matching lines @@
   } else if (type == kIsDirectory) {
     errno = EISDIR;
   } else {
     errno = EINVAL;
   }
   return false;
 }
 
 
 bool File::Copy(const char* old_path, const char* new_path) {
-  UNIMPLEMENTED();
+  File::Type type = File::GetType(old_path, true);
+  if (type == kIsFile) {

[zra, 2016/12/19 20:29:01]

This is copied from the Linux implementation with the attempt to use sendfile()
removed.

+    struct stat64 st;
+    if (NO_RETRY_EXPECTED(stat64(old_path, &st)) != 0) {
+      return false;
+    }
+    int old_fd = NO_RETRY_EXPECTED(open64(old_path, O_RDONLY | O_CLOEXEC));
+    if (old_fd < 0) {
+      return false;
+    }
+    int new_fd = NO_RETRY_EXPECTED(
+        open64(new_path, O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, st.st_mode));
+    if (new_fd < 0) {
+      VOID_TEMP_FAILURE_RETRY(close(old_fd));
+      return false;
+    }
+    // TODO(MG-429): Use sendfile/copyfile or equivalent when there is one.
+    intptr_t result;
+    const intptr_t kBufferSize = 8 * KB;
+    uint8_t buffer[kBufferSize];
+    while ((result = NO_RETRY_EXPECTED(read(old_fd, buffer, kBufferSize))) >
+           0) {
+      int wrote = NO_RETRY_EXPECTED(write(new_fd, buffer, result));
+      if (wrote != result) {
+        result = -1;
+        break;
+      }
+    }
+    FDUtils::SaveErrorAndClose(old_fd);
+    FDUtils::SaveErrorAndClose(new_fd);
+    if (result < 0) {
+      int e = errno;
+      VOID_NO_RETRY_EXPECTED(unlink(new_path));
+      errno = e;
+      return false;
+    }
+    return true;
+  } else if (type == kIsDirectory) {
+    errno = EISDIR;
+  } else {
+    errno = ENOENT;
+  }
   return false;
 }
 
 
 int64_t File::LengthFromPath(const char* name) {
   struct stat st;
   if (NO_RETRY_EXPECTED(stat(name, &st)) == 0) {
     return st.st_size;
   }
   return -1;
@@ skipping 148 matching lines @@
   return ((file_1_info.st_ino == file_2_info.st_ino) &&
           (file_1_info.st_dev == file_2_info.st_dev))
              ? File::kIdentical
              : File::kDifferent;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)