ui/surface/transport_dib_sysvipc.cc

   1 // Copyright (c) 2012 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 "ui/surface/transport_dib.h"
   6
   7 // Desktop GTK Linux builds use the old-style SYSV SHM based DIBs.
   8 // Linux Aura and Chrome OS do too. This will change very soon.
   9 #if defined(TOOLKIT_GTK) || (defined(OS_LINUX) && defined(USE_AURA))
  10
  11 #include <errno.h>
  12 #include <stdlib.h>
  13 #include <sys/ipc.h>
  14 #include <sys/shm.h>
  15
  16 #include "base/logging.h"
  17 #include "base/memory/scoped_ptr.h"
  18 #include "skia/ext/platform_canvas.h"
  19 #include "ui/base/x/x11_util.h"
  20 #include "ui/gfx/size.h"
  21
  22 // The shmat system call uses this as it's invalid return address
  23 static void *const kInvalidAddress = (void*) -1;
  24
  25 TransportDIB::TransportDIB()
  26     : address_(kInvalidAddress),
  27       x_shm_(0),
  28       display_(NULL),
  29       inflight_counter_(0),
  30       detached_(false),
  31       size_(0) {
  32 }
  33
  34 TransportDIB::~TransportDIB() {
  35   if (address_ != kInvalidAddress) {
  36     shmdt(address_);
  37     address_ = kInvalidAddress;
  38   }
  39
  40   if (x_shm_) {
  41     DCHECK(display_);
  42     ui::DetachSharedMemory(display_, x_shm_);
  43   }
  44 }
  45
  46 // static
  47 TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
  48   const int shmkey = shmget(IPC_PRIVATE, size, 0600);
  49   if (shmkey == -1) {
  50     DLOG(ERROR) << "Failed to create SysV shared memory region"
  51                 << " errno:" << errno;
  52     return NULL;
  53   } else {
  54     VLOG(1) << "Created SysV shared memory region " << shmkey;
  55   }
  56
  57   void* address = shmat(shmkey, NULL /* desired address */, 0 /* flags */);
  58   // Here we mark the shared memory for deletion. Since we attached it in the
  59   // line above, it doesn't actually get deleted but, if we crash, this means
  60   // that the kernel will automatically clean it up for us.
  61   shmctl(shmkey, IPC_RMID, 0);
  62   if (address == kInvalidAddress)
  63     return NULL;
  64
  65   TransportDIB* dib = new TransportDIB;
  66
  67   dib->key_.shmkey = shmkey;
  68   dib->address_ = address;
  69   dib->size_ = size;
  70   return dib;
  71 }
  72
  73 // static
  74 TransportDIB* TransportDIB::Map(Handle handle) {
  75   scoped_ptr<TransportDIB> dib(CreateWithHandle(handle));
  76   if (!dib->Map())
  77     return NULL;
  78   return dib.release();
  79 }
  80
  81 // static
  82 TransportDIB* TransportDIB::CreateWithHandle(Handle shmkey) {
  83   TransportDIB* dib = new TransportDIB;
  84   dib->key_.shmkey = shmkey;
  85   return dib;
  86 }
  87
  88 // static
  89 bool TransportDIB::is_valid_handle(Handle dib) {
  90   return dib >= 0;
  91 }
  92
  93 // static
  94 bool TransportDIB::is_valid_id(Id id) {
  95   return id.shmkey != -1;
  96 }
  97
  98 skia::PlatformCanvas* TransportDIB::GetPlatformCanvas(int w, int h) {
  99   if ((address_ == kInvalidAddress && !Map()) || !VerifyCanvasSize(w, h))
 100     return NULL;
 101   return skia::CreatePlatformCanvas(w, h, true,
 102                                     reinterpret_cast<uint8_t*>(memory()),
 103                                     skia::RETURN_NULL_ON_FAILURE);
 104 }
 105
 106 bool TransportDIB::Map() {
 107   if (!is_valid_id(key_))
 108     return false;
 109   if (address_ != kInvalidAddress)
 110     return true;
 111
 112   struct shmid_ds shmst;
 113   if (shmctl(key_.shmkey, IPC_STAT, &shmst) == -1)
 114     return false;
 115
 116   void* address = shmat(key_.shmkey, NULL /* desired address */, 0 /* flags */);
 117   if (address == kInvalidAddress)
 118     return false;
 119
 120   address_ = address;
 121   size_ = shmst.shm_segsz;
 122   return true;
 123 }
 124
 125 void* TransportDIB::memory() const {
 126   DCHECK_NE(address_, kInvalidAddress);
 127   return address_;
 128 }
 129
 130 TransportDIB::Id TransportDIB::id() const {
 131   return key_;
 132 }
 133
 134 TransportDIB::Handle TransportDIB::handle() const {
 135   return key_.shmkey;
 136 }
 137
 138 XID TransportDIB::MapToX(Display* display) {
 139   if (!x_shm_) {
 140     x_shm_ = ui::AttachSharedMemory(display, key_.shmkey);
 141     display_ = display;
 142   }
 143
 144   return x_shm_;
 145 }
 146
 147 void TransportDIB::DecreaseInFlightCounter() {
 148   CHECK(inflight_counter_);
 149   inflight_counter_--;
 150   if (!inflight_counter_ && detached_)
 151     delete this;
 152 }
 153
 154 void TransportDIB::Detach() {
 155   CHECK(!detached_);
 156   detached_ = true;
 157   if (!inflight_counter_)
 158     delete this;
 159 }
 160
 161 #endif
 162