Implement SysInfo::HardwareModelName() on iOS.

base/sys_info_mac.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/sys_info.h"
 
 #include <ApplicationServices/ApplicationServices.h>
 #include <CoreServices/CoreServices.h>
 #import <Foundation/Foundation.h>
 #include <mach/mach_host.h>
 #include <mach/mach_init.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <sys/sysctl.h>
 #include <sys/types.h>
 
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_mach_port.h"
 #import "base/mac/sdk_forward_declarations.h"
 #include "base/macros.h"
 #include "base/process/process_metrics.h"
 #include "base/strings/stringprintf.h"
 
 namespace base {
 
+namespace {
+
+// Queries sysctlbyname() for the given key and returns the value from the
+// system or the empty string on failure.
+std::string GetSysctlValue(const char* key_name) {
+  char value[256];
+  size_t len = arraysize(value);
+  if (sysctlbyname(key_name, &value, &len, nullptr, 0) == 0) {
+    DCHECK_GE(len, 1u);
+    DCHECK_EQ('\0', value[len - 1]);
+    return std::string(value, len - 1);
+  }
+  return std::string();
+}
+
+}  // namespace
+
 // static
 std::string SysInfo::OperatingSystemName() {
   return "Mac OS X";
 }
 
 // static
 std::string SysInfo::OperatingSystemVersion() {
   int32_t major, minor, bugfix;
   OperatingSystemVersionNumbers(&major, &minor, &bugfix);
   return base::StringPrintf("%d.%d.%d", major, minor, bugfix);
@@ skipping 50 matching lines @@
   SystemMemoryInfoKB info;
   if (!GetSystemMemoryInfo(&info))
     return 0;
   // We should add inactive file-backed memory also but there is no such
   // information from Mac OS unfortunately.
   return static_cast<int64_t>(info.free + info.speculative) * 1024;
 }
 
 // static
 std::string SysInfo::CPUModelName() {
-  char name[256];
-  size_t len = arraysize(name);
-  if (sysctlbyname("machdep.cpu.brand_string", &name, &len, NULL, 0) == 0)
-    return name;
-  return std::string();
+  return GetSysctlValue("machdep.cpu.brand_string");
 }
 
+// static
 std::string SysInfo::HardwareModelName() {
-  char model[256];
-  size_t len = sizeof(model);
-  if (sysctlbyname("hw.model", model, &len, NULL, 0) == 0)
-    return std::string(model, 0, len);
-  return std::string();
+  return GetSysctlValue("hw.model");
 }
 
 }  // namespace base