content/child/web_process_memory_dump_impl.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/child/web_process_memory_dump_impl.h"
   6
   7 #include "base/trace_event/process_memory_dump.h"
   8 #include "content/child/web_memory_allocator_dump_impl.h"
   9
  10 namespace content {
  11
  12 WebProcessMemoryDumpImpl::WebProcessMemoryDumpImpl()
  13     : owned_process_memory_dump_(
  14           new base::trace_event::ProcessMemoryDump(nullptr)),
  15       process_memory_dump_(owned_process_memory_dump_.get()) {
  16 }
  17
  18 WebProcessMemoryDumpImpl::WebProcessMemoryDumpImpl(
  19     base::trace_event::ProcessMemoryDump* process_memory_dump)
  20     : process_memory_dump_(process_memory_dump) {
  21 }
  22
  23 WebProcessMemoryDumpImpl::~WebProcessMemoryDumpImpl() {
  24 }
  25
  26 blink::WebMemoryAllocatorDump*
  27 WebProcessMemoryDumpImpl::createMemoryAllocatorDump(
  28     const blink::WebString& absolute_name) {
  29   // Get a MemoryAllocatorDump from the base/ object.
  30   base::trace_event::MemoryAllocatorDump* memory_allocator_dump =
  31       process_memory_dump_->CreateAllocatorDump(absolute_name.utf8());
  32   if (!memory_allocator_dump)
  33     return nullptr;
  34
  35   // Wrap it and return to blink.
  36   WebMemoryAllocatorDumpImpl* web_memory_allocator_dump_impl =
  37       new WebMemoryAllocatorDumpImpl(memory_allocator_dump);
  38
  39   // memory_allocator_dumps_ will take ownership of
  40   // |web_memory_allocator_dumpd_impl|.
  41   memory_allocator_dumps_.set(memory_allocator_dump,
  42                               make_scoped_ptr(web_memory_allocator_dump_impl));
  43
  44   return web_memory_allocator_dump_impl;
  45 }
  46
  47 blink::WebMemoryAllocatorDump* WebProcessMemoryDumpImpl::getMemoryAllocatorDump(
  48     const blink::WebString& absolute_name) const {
  49   // Retrieve the base MemoryAllocatorDump object and then reverse lookup
  50   // its wrapper.
  51   base::trace_event::MemoryAllocatorDump* memory_allocator_dump =
  52       process_memory_dump_->GetAllocatorDump(absolute_name.utf8());
  53   if (!memory_allocator_dump)
  54     return nullptr;
  55
  56   // The only case of (memory_allocator_dump && !web_memory_allocator_dump)
  57   // is something from blink trying to get a MAD that was created from chromium,
  58   // which is an odd use case.
  59   blink::WebMemoryAllocatorDump* web_memory_allocator_dump =
  60       memory_allocator_dumps_.get(memory_allocator_dump);
  61   DCHECK(web_memory_allocator_dump);
  62   return web_memory_allocator_dump;
  63 }
  64
  65 void WebProcessMemoryDumpImpl::clear() {
  66   // Clear all the WebMemoryAllocatorDump wrappers.
  67   memory_allocator_dumps_.clear();
  68
  69   // Clear the actual MemoryAllocatorDump objects from the underlying PMD.
  70   process_memory_dump_->Clear();
  71 }
  72
  73 void WebProcessMemoryDumpImpl::takeAllDumpsFrom(
  74     blink::WebProcessMemoryDump* other) {
  75   auto other_impl = static_cast<WebProcessMemoryDumpImpl*>(other);
  76   // WebProcessMemoryDumpImpl is a container of WebMemoryAllocatorDump(s) which
  77   // in turn are wrappers of base::trace_event::MemoryAllocatorDump(s).
  78   // In order to expose the move and ownership transfer semantics of the
  79   // underlying ProcessMemoryDump, we need to:
  80
  81   // 1) Move and transfer the ownership of the wrapped
  82   // base::trace_event::MemoryAllocatorDump(s) instances.
  83   process_memory_dump_->TakeAllDumpsFrom(other_impl->process_memory_dump_);
  84
  85   // 2) Move and transfer the ownership of the WebMemoryAllocatorDump wrappers.
  86   const size_t expected_final_size = memory_allocator_dumps_.size() +
  87                                      other_impl->memory_allocator_dumps_.size();
  88   while (!other_impl->memory_allocator_dumps_.empty()) {
  89     auto first_entry = other_impl->memory_allocator_dumps_.begin();
  90     base::trace_event::MemoryAllocatorDump* memory_allocator_dump =
  91         first_entry->first;
  92     memory_allocator_dumps_.set(
  93         memory_allocator_dump,
  94         other_impl->memory_allocator_dumps_.take_and_erase(first_entry).Pass());
  95   }
  96   DCHECK_EQ(expected_final_size, memory_allocator_dumps_.size());
  97   DCHECK(other_impl->memory_allocator_dumps_.empty());
  98 }
  99
 100 }  // namespace content