1 files changed, 89 insertions, 0 deletions
diff --git a/dom/media/gmp/GMPSharedMemManager.cpp b/dom/media/gmp/GMPSharedMemManager.cpp
new file mode 100644
index 0000000000..5da04247cb
--- /dev/null
+++ b/dom/media/gmp/GMPSharedMemManager.cpp
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GMPSharedMemManager.h"
+#include "GMPMessageUtils.h"
+#include "mozilla/ipc/SharedMemory.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/ClearOnShutdown.h"
+
+namespace mozilla::gmp {
+
+// Really one set of pools on each side of the plugin API.
+
+// YUV buffers go from Encoder parent to child; pool there, and then return
+// with Decoded() frames to the Decoder parent and goes into the parent pool.
+// Compressed (encoded) data goes from the Decoder parent to the child;
+// pool there, and then return with Encoded() frames and goes into the parent
+// pool.
+bool GMPSharedMemManager::MgrAllocShmem(GMPSharedMem::GMPMemoryClasses aClass,
+                                        size_t aSize, ipc::Shmem* aMem) {
+  mData->CheckThread();
+
+  // first look to see if we have a free buffer large enough
+  for (uint32_t i = 0; i < GetGmpFreelist(aClass).Length(); i++) {
+    MOZ_ASSERT(GetGmpFreelist(aClass)[i].IsWritable());
+    if (aSize <= GetGmpFreelist(aClass)[i].Size<uint8_t>()) {
+      *aMem = GetGmpFreelist(aClass)[i];
+      GetGmpFreelist(aClass).RemoveElementAt(i);
+      return true;
+    }
+  }
+
+  // Didn't find a buffer free with enough space; allocate one
+  size_t pagesize = ipc::SharedMemory::SystemPageSize();
+  aSize = (aSize + (pagesize - 1)) & ~(pagesize - 1);  // round up to page size
+  bool retval = Alloc(aSize, aMem);
+  if (retval) {
+    // The allocator (or NeedsShmem call) should never return less than we ask
+    // for...
+    MOZ_ASSERT(aMem->Size<uint8_t>() >= aSize);
+    mData->mGmpAllocated[aClass]++;
+  }
+  return retval;
+}
+
+bool GMPSharedMemManager::MgrDeallocShmem(GMPSharedMem::GMPMemoryClasses aClass,
+                                          ipc::Shmem& aMem) {
+  mData->CheckThread();
+
+  size_t size = aMem.Size<uint8_t>();
+
+  // XXX Bug NNNNNNN Until we put better guards on ipc::shmem, verify we
+  // weren't fed an shmem we already had.
+  for (uint32_t i = 0; i < GetGmpFreelist(aClass).Length(); i++) {
+    if (NS_WARN_IF(aMem == GetGmpFreelist(aClass)[i])) {
+      // Safest to crash in this case; should never happen in normal
+      // operation.
+      MOZ_CRASH("Deallocating Shmem we already have in our cache!");
+      // return true;
+    }
+  }
+
+  // XXX This works; there are better pool algorithms.  We need to avoid
+  // "falling off a cliff" with too low a number
+  if (GetGmpFreelist(aClass).Length() > 10) {
+    Dealloc(std::move(GetGmpFreelist(aClass)[0]));
+    GetGmpFreelist(aClass).RemoveElementAt(0);
+    // The allocation numbers will be fubar on the Child!
+    mData->mGmpAllocated[aClass]--;
+  }
+  for (uint32_t i = 0; i < GetGmpFreelist(aClass).Length(); i++) {
+    MOZ_ASSERT(GetGmpFreelist(aClass)[i].IsWritable());
+    if (size < GetGmpFreelist(aClass)[i].Size<uint8_t>()) {
+      GetGmpFreelist(aClass).InsertElementAt(i, aMem);
+      return true;
+    }
+  }
+  GetGmpFreelist(aClass).AppendElement(aMem);
+
+  return true;
+}
+
+uint32_t GMPSharedMemManager::NumInUse(GMPSharedMem::GMPMemoryClasses aClass) {
+  return mData->mGmpAllocated[aClass] - GetGmpFreelist(aClass).Length();
+}
+
+}  // namespace mozilla::gmp