Added memory usage function to base.

webrtc/base/memory_usage.cc

+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/base/memory_usage.h"
+
+#if defined(WEBRTC_LINUX)
+#include <unistd.h>
+#include <cstdlib>
+#include <cstdio>
+#include <cstring>
+#elif defined(WEBRTC_MAC)
+#include <mach/mach.h>
+#elif defined(WEBRTC_WIN)
+#include <windows.h>
+#include <psapi.h>
+#endif
+
+#include "webrtc/base/logging.h"
+
+namespace rtc {
+
+int64_t GetProcessResidentSizeBytes() {
+#if defined(WEBRTC_LINUX)
+  FILE* file = fopen("/proc/self/statm", "r");
+  if (file == nullptr) {
+    LOG(LS_ERROR) << "Failed to open /proc/self/statm";
+    return -1;
+  }
+  int result = -1;
+  if (fscanf(file, "%*s%d", &result) != 1) {
+    fclose(file);
+    LOG(LS_ERROR) << "Failed to parse /proc/self/statm";
+    return -1;
+  }
+  fclose(file);
+  return static_cast<int64_t>(result) * sysconf(_SC_PAGESIZE);
+#elif defined(WEBRTC_MAC)
+  task_basic_info_64 info;
+  mach_msg_type_number_t info_count = TASK_BASIC_INFO_64_COUNT;
+  if (task_info(mach_task_self(), TASK_BASIC_INFO_64,
+                reinterpret_cast<task_info_t>(&info),
+                &info_count) != KERN_SUCCESS) {
+    LOG_ERR(LS_ERROR) << "task_info() failed";
+    return -1;
+  }
+  return info.resident_size;
+#elif defined(WEBRTC_WIN)
+  PROCESS_MEMORY_COUNTERS pmc;
+  if (GetProcessMemoryInfo(GetCurrentProcess(), &pmc, sizeof(pmc)) == 0) {
+    LOG_ERR(LS_ERROR) << "GetProcessMemoryInfo() failed";
+    return -1;
+  }
+  return pmc.WorkingSetSize;
+#else
+  // Not implemented yet.
+  static_assert(false,
+                "GetProcessVirtualMemoryUsageBytes() platform support not yet "
+                "implemented.");
+#endif
+}
+
+}  // namespace rtc