Mac: Implement about:memory.

chrome/browser/process_info_snapshot.h

+// Copyright (c) 2009 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.
+
+#ifndef CHROME_BROWSER_PROCESS_INFO_SNAPSHOT_H_
+#define CHROME_BROWSER_PROCESS_INFO_SNAPSHOT_H_
+
+#include <sys/types.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/process_util.h"
+
+// A class which captures process information at a given point in time when its
+// |Sample()| method is called. This information can then be probed by PID.
+// |Sample()| may take a while to complete, so if calling from the browser
+// process, only do so from the file thread. The current implementation, only on
+// Mac, pulls information from /bin/ps. /usr/bin/top provides much more
+// information about memory, but it has changed greatly from Mac OS 10.5.x to
+// 10.6.x, thereby raising future compatibility concerns. Moreover, the 10.6.x
+// version is less capable in terms of configuring output and its output is
+// harder to parse.
+// TODO(viettrungluu): This is currently only implemented and used on Mac, so
+// things are very Mac-specific. If this is ever implemented for other
+// platforms, we should subclass and add opaqueness (probably |ProcInfoEntry|
+// should be considered opaque).
+class ProcessInfoSnapshot {
+ public:
+  ProcessInfoSnapshot();
+  ~ProcessInfoSnapshot();
+
+  // Capture a snapshot of process memory information (by running ps) for the
+  // given list of PIDs. Call only from the file thread.
+  //   |pid_list| - list of |ProcessId|s on which to capture information.
+  //   returns - |true| if okay, |false| on error.
+  bool Sample(std::vector<base::ProcessId> pid_list);
+
+  // Reset all statistics (deallocating any memory allocated).
+  void Reset();
+
+  // Our basic structure for storing information about a process (the names are
+  // mostly self-explanatory). Note that |command| may not actually reflect the
+  // actual executable name; never trust it absolutely, and only take it
+  // half-seriously when it begins with '/'.
+  struct ProcInfoEntry {
+    base::ProcessId pid;
+    base::ProcessId ppid;
+    uid_t uid;
+    uid_t euid;
+    size_t rss;
+    size_t vsize;
+    std::string command;
+  };
+
+  // Get process information for a given PID.
+  //   |pid| - self-explanatory.
+  //   |proc_info| - place to put the process information.
+  //   returns - |true| if okay, |false| on error (including PID not found).
+  bool GetProcInfo(int pid,
+                   ProcInfoEntry* proc_info) const;
+
+  // Fills a |CommittedKBytes| with both resident and paged memory usage, as per
+  // its definition (or as close as we can manage). In the current (Mac)
+  // implementation, we map:
+  //                              vsize --> comm_priv,
+  //                                  0 --> comm_mapped,
+  //                                  0 --> comm_image;
+  //   in about:memory: virtual:private  =  comm_priv,
+  //                     virtual:mapped  =  comm_mapped.
+  // TODO(viettrungluu): Doing such a mapping is kind of ugly.
+  //   |pid| - self-explanatory.
+  //   |usage| - pointer to |CommittedBytes| to fill; zero-ed on error.
+  //   returns - |true| on success, |false| on error (including PID not found).
+  bool GetCommittedKBytesOfPID(int pid,
+                               base::CommittedKBytes* usage) const;
+
+  // Fills a |WorkingSetKBytes| containing resident private and shared memory,
+  // as per its definition (or as close as we can manage). In the current (Mac)
+  // implementation, we map:
+  //                              0 --> ws_priv,
+  //                            rss --> ws_shareable,
+  //                              0 --> ws_shared;
+  //   in about:memory: res:private  =  ws_priv + ws_shareable - ws_shared,
+  //                     res:shared  =  ws_shared / num_procs,
+  //                      res:total  =  res:private + res:shared.
+  // TODO(viettrungluu): Doing such a mapping is kind of ugly.
+  //   |pid| - self-explanatory.
+  //   |ws_usage| - pointer to |WorkingSetKBytes| to fill; zero-ed on error.
+  //   returns - |true| on success, |false| on error (including PID not found).
+  bool GetWorkingSetKBytesOfPID(int pid,
+                                base::WorkingSetKBytes* ws_usage) const;
+
+  // TODO(viettrungluu): Maybe we should also have the following (again, for
+  // "compatibility"):
+  //    size_t GetWorkingSetSizeOfPID(int pid) const;
+  //    size_t GetPeakWorkingSetSizeOfPID(int pid) const;
+  //    size_t GetPrivateBytesOfPID(int pid) const;
+
+ private:
+  // map from |int| (PID) to |ProcInfoEntry|
+  std::map<int,ProcInfoEntry> proc_info_entries_;
+};
+
+#endif  // CHROME_BROWSER_PROCESS_INFO_SNAPSHOT_H_