Really remove io support when dart:io is unsupported.

runtime/bin/file_support.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 "bin/file.h"
+
+#include "bin/builtin.h"
+#include "bin/dartutils.h"
+#include "bin/embedded_dart_io.h"
+#include "bin/io_buffer.h"
+#include "bin/utils.h"
+
+#include "include/dart_api.h"
+#include "include/dart_tools_api.h"
+
+namespace dart {
+namespace bin {
+
+// Are we capturing output from stdout for the VM service?
+static bool capture_stdout = false;
+
+// Are we capturing output from stderr for the VM service?
+static bool capture_stderr = false;
+
+void SetCaptureStdout(bool value) {
+  capture_stdout = value;
+}
+
+
+void SetCaptureStderr(bool value) {
+  capture_stderr = value;
+}
+
+
+bool ShouldCaptureStdout() {
+  return capture_stdout;
+}
+
+
+bool ShouldCaptureStderr() {
+  return capture_stderr;
+}
+
+
+bool File::ReadFully(void* buffer, int64_t num_bytes) {
+  int64_t remaining = num_bytes;
+  char* current_buffer = reinterpret_cast<char*>(buffer);
+  while (remaining > 0) {
+    int64_t bytes_read = Read(current_buffer, remaining);
+    if (bytes_read <= 0) {
+      return false;
+    }
+    remaining -= bytes_read;  // Reduce the number of remaining bytes.
+    current_buffer += bytes_read;  // Move the buffer forward.
+  }
+  return true;
+}
+
+
+bool File::WriteFully(const void* buffer, int64_t num_bytes) {
+  int64_t remaining = num_bytes;
+  const char* current_buffer = reinterpret_cast<const char*>(buffer);
+  while (remaining > 0) {
+    int64_t bytes_written = Write(current_buffer, remaining);
+    if (bytes_written < 0) {
+      return false;
+    }
+    remaining -= bytes_written;  // Reduce the number of remaining bytes.
+    current_buffer += bytes_written;  // Move the buffer forward.
+  }
+  if (capture_stdout || capture_stderr) {
+    intptr_t fd = GetFD();
+    if ((fd == STDOUT_FILENO) && capture_stdout) {
+      Dart_ServiceSendDataEvent("Stdout", "WriteEvent",
+                                reinterpret_cast<const uint8_t*>(buffer),
+                                num_bytes);
+    } else if ((fd == STDERR_FILENO) && capture_stderr) {
+      Dart_ServiceSendDataEvent("Stderr", "WriteEvent",
+                                reinterpret_cast<const uint8_t*>(buffer),
+                                num_bytes);
+    }
+  }
+  return true;
+}
+
+
+File::FileOpenMode File::DartModeToFileMode(DartFileOpenMode mode) {
+  ASSERT((mode == File::kDartRead) ||
+         (mode == File::kDartWrite) ||
+         (mode == File::kDartAppend) ||
+         (mode == File::kDartWriteOnly) ||
+         (mode == File::kDartWriteOnlyAppend));
+  if (mode == File::kDartWrite) {
+    return File::kWriteTruncate;
+  }
+  if (mode == File::kDartAppend) {
+    return File::kWrite;
+  }
+  if (mode == File::kDartWriteOnly) {
+    return File::kWriteOnlyTruncate;
+  }
+  if (mode == File::kDartWriteOnlyAppend) {
+    return File::kWriteOnly;
+  }
+  return File::kRead;
+}
+
+}  // namespace bin
+}  // namespace dart