Refactors CPU feature detection.

runtime/vm/cpuinfo_macos.cc

Index: runtime/vm/cpuinfo_macos.cc
===================================================================
--- runtime/vm/cpuinfo_macos.cc	(revision 0)
+++ runtime/vm/cpuinfo_macos.cc	(revision 0)
@@ -0,0 +1,63 @@
+// Copyright (c) 2012, 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 "vm/globals.h"
+#if defined(TARGET_OS_MACOS)
+
+#include "vm/cpuinfo.h"
+
+#include <errno.h>  // NOLINT
+#include <sys/types.h>  // NOLINT
+#include <sys/sysctl.h>  // NOLINT
+
+#include "platform/assert.h"
+
+namespace dart {
+
+char* CpuInfo::data_ = NULL;
+intptr_t CpuInfo::datalen_ = 0;
+
+// No-op on MacOS.
+void CpuInfo::Read() {}
+
+
+bool CpuInfo::FieldContains(const char* field, const char* search_string) {
+  ASSERT(search_string != NULL);
+  char dest[1024];
+
+  ExtractField(field, dest, 1024);
+
+  return (strcasestr(dest, search_string) != NULL);
+}
+
+
+intptr_t CpuInfo::ExtractField(
+    const char* field, char* dest, const intptr_t dest_len) {
+  ASSERT(field != NULL);
+
+  size_t ret_len = dest_len;
+  if (sysctlbyname(field, dest, &ret_len, NULL, 0) != 0) {
+    UNREACHABLE();
+    return 0;
+  }
+
+  return ret_len;
+}
+
+
+bool CpuInfo::HasField(const char* field) {
+  ASSERT(field != NULL);
+  int ret = sysctlbyname(field, NULL, NULL, NULL, 0);
+  return (ret != ENOENT);
+}
+
+
+intptr_t CpuInfo::GetCpuModel(char* dest, const intptr_t dest_len) {
+  ASSERT(HasField("machdep.cpu.brand_string"));
+  return ExtractField("machdep.cpu.brand_string", dest, dest_len);
+}
+
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_MACOS)