Parsing /proc/cpuinfo for model on Android and Aura

base/cpu.cc

Index: base/cpu.cc
diff --git a/base/cpu.cc b/base/cpu.cc
index 66207a1e0b8b0539b99a72b85435936f847803bb..b22d8e664d04892d83ad84271f6bad602cf666f9 100644
--- a/base/cpu.cc
+++ b/base/cpu.cc
@@ -9,6 +9,8 @@
 #include <algorithm>
 
 #include "base/basictypes.h"
+#include "base/file_util.h"
+#include "base/lazy_instance.h"
 #include "build/build_config.h"
 
 #if defined(ARCH_CPU_X86_FAMILY)
@@ -86,6 +88,51 @@ uint64 _xgetbv(uint32 xcr) {
 
 }  // anonymous namespace
 
+#if defined(ARCH_CPU_ARM_FAMILY)
+#if defined(OS_ANDROID) || defined(USE_AURA)
+
+std::string CpuBrandInfo() {
+  const char kProcessorPrefix[] = "Processor";
+  std::string contents, cpu_brand;
+  ReadFileToString(FilePath("/proc/cpuinfo"), &contents);
+  DCHECK(!contents.empty());
+  if (!contents.empty()) {
+    std::istringstream iss(contents);
+    std::string line;
+    while (std::getline(iss, line)) {
+      if (line.compare(0, strlen(kProcessorPrefix), kProcessorPrefix) == 0) {
+        size_t pos = line.find(": ");
+        if (pos != std::string::npos) {

[rptr, 2014/03/08 13:03:06]

Takes care of review comment if ": " is not found in Processor string.

+          cpu_brand.assign(line.substr(pos + 2));
+          break;

[rptr, 2014/03/08 13:03:06]

Takes care of review comment: Do file lookup untill Processor line is found or
EOF.

+        }
+      }
+    }
+  }
+  return cpu_brand;
+}
+
+template <typename T, T (*F)(void)>

[rptr, 2014/03/08 13:03:06]

Perform cpu brand caching using lazy instance as suggested by review comments.

[Mark Mentovai, 2014/03/10 14:16:24]

Why is this templated? You only use it once.

[rptr, 2014/03/11 15:47:14]

Done.

+class LazyCpuInfoValue {
+ public:
+  LazyCpuInfoValue() : value_(F()) {}
+  ~LazyCpuInfoValue() {}
+  T value() { return value_; }
+
+ private:
+  const T value_;
+  DISALLOW_COPY_AND_ASSIGN(LazyCpuInfoValue);
+};
+
+base::LazyInstance<LazyCpuInfoValue<std::string, CpuBrandInfo> >::Leaky
+    g_lazy_cpu_brand = LAZY_INSTANCE_INITIALIZER;
+
+// static
+std::string CPU::CpuBrandInfo() { return g_lazy_cpu_brand.Get().value(); }

[Mark Mentovai, 2014/03/10 14:16:24]

Why not a const string&?

[rptr, 2014/03/11 15:47:14]

Done.

+
+#endif  // defined(OS_ANDROID) || defined(USE_AURA)
+#endif  // ARCH_CPU_ARM_FAMILY
+
 void CPU::Initialize() {
 #if defined(ARCH_CPU_X86_FAMILY)
   int cpu_info[4] = {-1};
@@ -158,12 +205,9 @@ void CPU::Initialize() {
     has_non_stop_time_stamp_counter_ = (cpu_info[3] & (1 << 8)) != 0;
   }
 #elif defined(ARCH_CPU_ARM_FAMILY)
-  // TODO(piman): Expand this. ARM has a CPUID register, but it's not available
-  // in user mode. /proc/cpuinfo has some information, but it's non standard,
-  // platform-specific, and not accessible from the sandbox.
-  // For some purposes, this first approximation is enough.
-  // crbug.com/313454
-  cpu_brand_.assign("ARM");
+#if defined(OS_ANDROID) || defined(USE_AURA)

[Mark Mentovai, 2014/03/10 14:16:24]

What’s this got to do with Aura?

[rptr, 2014/03/11 15:47:14]

My understanding is that (from comments of piman and siva in crbug:313454)
ARCH_CPU_ARM is currently run on android and linux with aura. Please correct me
if its wrong.

+  cpu_brand_.assign(CPU::CpuBrandInfo());
+#endif
 #endif
 }