Refactors CPU feature detection.

runtime/vm/cpuinfo.h

+// 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.
+
+#ifndef VM_CPUINFO_H_
+#define VM_CPUINFO_H_
+
+#include "platform/assert.h"
+#include "vm/allocation.h"
+
+namespace dart {
+
+class CpuInfo : public AllStatic {
+ public:
+  // Indices into cpuinfo field name arrays.
+  enum CpuInfoIndices {
+    kCpuInfoProcessor = 0,
+    kCpuInfoModel = 1,
+    kCpuInfoFeatures = 2,
+    kCpuInfoMax = 3,
+  };
+
+  // If necessary, allocates a buffer [data_] and reads cpuinfo into
+  // that buffer.
+  static void InitOnce();
+
+  static const char* FieldName(CpuInfoIndices idx) {
+    ASSERT((idx >= 0) && (idx < kCpuInfoMax));
+    return fields_[idx];
+  }
+
+  // Returns true if the cpuinfo field [field] contains the
+  // string [search_string].
+  static bool FieldContains(const char* field, const char* search_string);
+  static bool FieldContainsById(CpuInfoIndices idx, const char* search_string) {
+    return FieldContains(FieldName(idx), search_string);
+  }
+
+  // Returns true if the cpuinfo field [field] exists and is non-empty.
+  static bool HasField(const char* field);
+
+  // Reads the cpuinfo field [field] into the buffer [dest] and returns the
+  // length of the field.
+  // If [dest] is NULL, ExtractField just returns the length.
+  static char* ExtractField(const char* field);
+
+  // Reads the cpuinfo field describing the CPU model into the buffer [dest].
+  static char* GetCpuModel() {
+    ASSERT(HasField(FieldName(kCpuInfoModel)));
+    return ExtractField(FieldName(kCpuInfoModel));
+  }
+
+ private:
+  // On Linux and Android data_ holds /proc/cpuinfo after Read().
+  static char* data_;
+
+  // On Linux and Android, the length of /proc/cpuinfo.
+  static intptr_t datalen_;
+
+  // Fills in the fields_ array.
+  static void InitializeFields();
+
+  // Cpuinfo field names.
+  static const char* fields_[kCpuInfoMax];
+};
+
+}  // namespace dart
+
+#endif  // VM_CPUINFO_H_