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