PPAPI: Upgrade video decoder host shared memory API.
Use an UnsafeSharedMemoryRegion instead of the existing handle. The
shared memory on the host side is used read-only, but because a
writable region needs to be shipped to the other side of the proxy, an
unsafe region needs to be used.
Host | Other side of proxy
-----------------------------+---------------------------------
| Request SHM
Create SHM <-----------------------/
Reply with SHM Handle |
| \-------------------------> Receive SHM
Save SHM by ID |
|
| Fill SHM with video to decode
| (write to SHM)
| Send SHM ID to Host
Receive decode request <-----------/
Look up buffer by ID |
Decode what's in the SHM |
(read-only SHM access)
The host-side could use a read-only region only by adding an additional
round-trip, with the other side of the proxy either converting to
read-only after mapping writable, and shipping back to the host,
or the other side of the proxy mapping, shipping back a writable
handle, and then the host converting to read-only. This has not been
done in this CL.
Bug: 849207
Change-Id: I3e50f9ff9c65e51c21c7e4d72b3aed2402c03196
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1615021
Commit-Queue: Matthew Cary (CET) <[email protected]>
Reviewed-by: Chris Palmer <[email protected]>
Reviewed-by: Antoine Labour <[email protected]>
Reviewed-by: Bill Budge <[email protected]>
Cr-Commit-Position: refs/heads/master@{#666194}
diff --git a/ppapi/proxy/video_decoder_resource.cc b/ppapi/proxy/video_decoder_resource.cc
index 94548e14..ad00255 100644
--- a/ppapi/proxy/video_decoder_resource.cc
+++ b/ppapi/proxy/video_decoder_resource.cc
@@ -32,12 +32,12 @@
namespace proxy {
VideoDecoderResource::ShmBuffer::ShmBuffer(
- std::unique_ptr<base::SharedMemory> shm_ptr,
- uint32_t size,
+ base::UnsafeSharedMemoryRegion region,
uint32_t shm_id)
- : shm(std::move(shm_ptr)), addr(NULL), shm_id(shm_id) {
- if (shm->Map(size))
- addr = shm->memory();
+ : region(std::move(region)), shm_id(shm_id) {
+ mapping = this->region.Map();
+ if (mapping.IsValid())
+ addr = mapping.memory();
}
VideoDecoderResource::ShmBuffer::~ShmBuffer() {
@@ -199,7 +199,7 @@
decode_ids_[uid % kMaximumPictureDelay] = decode_id;
if (available_shm_buffers_.empty() ||
- available_shm_buffers_.back()->shm->mapped_size() < size) {
+ available_shm_buffers_.back()->mapping.size() < size) {
uint32_t shm_id;
if (shm_buffers_.size() < kMaximumPendingDecodes) {
// Signal the host to create a new shm buffer by passing an index outside
@@ -227,13 +227,12 @@
if (!UnpackMessage<PpapiPluginMsg_VideoDecoder_GetShmReply>(reply,
&shm_size))
return PP_ERROR_FAILED;
- base::SharedMemoryHandle shm_handle;
- if (!reply_params.TakeSharedMemoryHandleAtIndex(0, &shm_handle))
+ base::UnsafeSharedMemoryRegion shm_region;
+ if (!reply_params.TakeUnsafeSharedMemoryRegionAtIndex(0, &shm_region) ||
+ !shm_region.IsValid() || shm_region.GetSize() != shm_size)
return PP_ERROR_NOMEMORY;
- std::unique_ptr<base::SharedMemory> shm(
- new base::SharedMemory(shm_handle, false /* read_only */));
std::unique_ptr<ShmBuffer> shm_buffer(
- new ShmBuffer(std::move(shm), shm_size, shm_id));
+ new ShmBuffer(std::move(shm_region), shm_id));
if (!shm_buffer->addr)
return PP_ERROR_NOMEMORY;
@@ -246,7 +245,7 @@
// At this point we should have shared memory to hold the plugin's buffer.
DCHECK(!available_shm_buffers_.empty() &&
- available_shm_buffers_.back()->shm->mapped_size() >= size);
+ available_shm_buffers_.back()->mapping.size() >= size);
ShmBuffer* shm_buffer = available_shm_buffers_.back();
available_shm_buffers_.pop_back();
