gecko/memory/mozalloc/VolatileBufferAshmem.cpp
Mike Hommey b08088c7c1 Bug 1077366 - Remove most symbol wrapping from Android builds. r=nfroyd
Since essentially everything is linked to libmozglue and libmozglue takes
precedence in symbol resolution in our dynamic linker, there is no need
to wrap most symbols. PR_GetEnv/PR_SetEnv still needs wrapping because
there's no other way to actually wrap the calls from NSPR itself and NSS,
as well as the symbols wrapped because our dynamic linker can't find them
in system libraries on some devices because they're weak.
2014-10-14 07:17:13 +09:00

134 lines
2.5 KiB
C++

/* 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 "VolatileBuffer.h"
#include "mozilla/Assertions.h"
#include "mozilla/NullPtr.h"
#include "mozilla/mozalloc.h"
#include <fcntl.h>
#include <linux/ashmem.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#ifdef MOZ_MEMORY
extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size);
#endif
#define MIN_VOLATILE_ALLOC_SIZE 8192
namespace mozilla {
VolatileBuffer::VolatileBuffer()
: mBuf(nullptr)
, mSize(0)
, mLockCount(0)
, mFd(-1)
{
}
bool
VolatileBuffer::Init(size_t aSize, size_t aAlignment)
{
MOZ_ASSERT(!mSize && !mBuf, "Init called twice");
MOZ_ASSERT(!(aAlignment % sizeof(void *)),
"Alignment must be multiple of pointer size");
mSize = aSize;
if (aSize < MIN_VOLATILE_ALLOC_SIZE) {
goto heap_alloc;
}
mFd = open("/" ASHMEM_NAME_DEF, O_RDWR);
if (mFd < 0) {
goto heap_alloc;
}
if (ioctl(mFd, ASHMEM_SET_SIZE, mSize) < 0) {
goto heap_alloc;
}
mBuf = mmap(nullptr, mSize, PROT_READ | PROT_WRITE, MAP_SHARED, mFd, 0);
if (mBuf != MAP_FAILED) {
return true;
}
heap_alloc:
mBuf = nullptr;
if (mFd >= 0) {
close(mFd);
mFd = -1;
}
#ifdef MOZ_MEMORY
posix_memalign(&mBuf, aAlignment, aSize);
#else
mBuf = memalign(aAlignment, aSize);
#endif
return !!mBuf;
}
VolatileBuffer::~VolatileBuffer()
{
if (OnHeap()) {
free(mBuf);
} else {
munmap(mBuf, mSize);
close(mFd);
}
}
bool
VolatileBuffer::Lock(void** aBuf)
{
MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
*aBuf = mBuf;
if (++mLockCount > 1 || OnHeap()) {
return true;
}
// Zero offset and zero length means we want to pin/unpin the entire thing.
struct ashmem_pin pin = { 0, 0 };
return ioctl(mFd, ASHMEM_PIN, &pin) == ASHMEM_NOT_PURGED;
}
void
VolatileBuffer::Unlock()
{
MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!");
if (--mLockCount || OnHeap()) {
return;
}
struct ashmem_pin pin = { 0, 0 };
ioctl(mFd, ASHMEM_UNPIN, &pin);
}
bool
VolatileBuffer::OnHeap() const
{
return mFd < 0;
}
size_t
VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
{
return OnHeap() ? aMallocSizeOf(mBuf) : 0;
}
size_t
VolatileBuffer::NonHeapSizeOfExcludingThis() const
{
if (OnHeap()) {
return 0;
}
return (mSize + (PAGE_SIZE - 1)) & PAGE_MASK;
}
} // namespace mozilla