impeller::android::HardwareBuffer Class Reference

A wrapper for AHardwareBuffer https://developer.android.com/ndk/reference/group/a-hardware-buffer. More...

#include <hardware_buffer.h>

Public Types
enum class	CPUAccessType { kRead , kWrite }

Public Member Functions
	HardwareBuffer (HardwareBufferDescriptor descriptor)
	~HardwareBuffer ()
	HardwareBuffer (const HardwareBuffer &)=delete
HardwareBuffer &	operator= (const HardwareBuffer &)=delete
bool	IsValid () const
AHardwareBuffer *	GetHandle () const
const HardwareBufferDescriptor &	GetDescriptor () const
const AHardwareBuffer_Desc &	GetAndroidDescriptor () const
std::optional< uint64_t >	GetSystemUniqueID () const
	Get the system wide unique ID of the hardware buffer if possible. This is only available on Android API 31 and above. Within the process, the handle are unique. More...
void *	Lock (CPUAccessType type) const
	Lock the buffer for CPU access. This call may fail if the buffer was not created with one the usages that allow for CPU access. More...
bool	Unlock () const
	Unlock a mapping previously locked for CPU access. More...

Static Public Member Functions
static bool	IsAvailableOnPlatform ()
static std::optional< AHardwareBuffer_Desc >	Describe (AHardwareBuffer *buffer)
static std::optional< uint64_t >	GetSystemUniqueID (AHardwareBuffer *buffer)
	Get the system wide unique ID of the hardware buffer if possible. This is only available on Android API 31 and above. Within the process, the handle are unique. More...

Detailed Description

A wrapper for AHardwareBuffer https://developer.android.com/ndk/reference/group/a-hardware-buffer.

This wrapper creates and owns a handle to a managed hardware buffer. That is, there is no ability to take a reference to an externally created hardware buffer.

This wrapper is only available on Android API 29 and above.

Definition at line 95 of file hardware_buffer.h.

Member Enumeration Documentation

CPUAccessType

enum class impeller::android::HardwareBuffer::CPUAccessType

strong

Enumerator
kRead
kWrite

Definition at line 135 of file hardware_buffer.h.

                           {
    kRead,
    kWrite,
  };

Constructor & Destructor Documentation

HardwareBuffer() [1/2]

impeller::android::HardwareBuffer::HardwareBuffer ( HardwareBufferDescriptor  descriptor )

explicit

Definition at line 57 of file hardware_buffer.cc.

    : descriptor_(descriptor),
      android_descriptor_(ToAHardwareBufferDesc(descriptor_)) {
  if (!descriptor_.IsAllocatable()) {
    VALIDATION_LOG << "The hardware buffer descriptor is not allocatable.";
    return;
  }
  const auto& proc_table = GetProcTable();
 
  AHardwareBuffer* buffer = nullptr;
  if (auto result =
          proc_table.AHardwareBuffer_allocate(&android_descriptor_, &buffer);
      result != 0 || buffer == nullptr) {
    VALIDATION_LOG << "Could not allocate hardware buffer. Error: " << result;
    return;
  }
  buffer_.reset(buffer);
  is_valid_ = true;
}

~HardwareBuffer()

impeller::android::HardwareBuffer::~HardwareBuffer ( )

default

HardwareBuffer() [2/2]

impeller::android::HardwareBuffer::HardwareBuffer ( const HardwareBuffer &  )

delete

Member Function Documentation

Describe()

std::optional< AHardwareBuffer_Desc > impeller::android::HardwareBuffer::Describe ( AHardwareBuffer *  buffer )

static

Definition at line 127 of file hardware_buffer.cc.

                             {
  if (!buffer || !GetProcTable().AHardwareBuffer_describe) {
    return std::nullopt;
  }
  AHardwareBuffer_Desc desc = {};
  GetProcTable().AHardwareBuffer_describe(buffer, &desc);
  return desc;
}

GetAndroidDescriptor()

const AHardwareBuffer_Desc & impeller::android::HardwareBuffer::GetAndroidDescriptor

(

)

const

Definition at line 103 of file hardware_buffer.cc.

                                                                       {
  return android_descriptor_;
}

GetDescriptor()

const HardwareBufferDescriptor & impeller::android::HardwareBuffer::GetDescriptor

(

)

const

Definition at line 99 of file hardware_buffer.cc.

                                                                    {
  return descriptor_;
}

GetHandle()

AHardwareBuffer * impeller::android::HardwareBuffer::GetHandle

(

)

const

Definition at line 83 of file hardware_buffer.cc.

                                                 {
  return buffer_.get();
}

GetSystemUniqueID() [1/2]

std::optional< uint64_t > impeller::android::HardwareBuffer::GetSystemUniqueID

(

)

const

Get the system wide unique ID of the hardware buffer if possible. This is only available on Android API 31 and above. Within the process, the handle are unique.

Returns

The system unique id if one can be obtained.

Definition at line 111 of file hardware_buffer.cc.

                                                              {
  return GetSystemUniqueID(GetHandle());
}

GetSystemUniqueID() [2/2]

std::optional< uint64_t > impeller::android::HardwareBuffer::GetSystemUniqueID ( AHardwareBuffer *  buffer )

static

Get the system wide unique ID of the hardware buffer if possible. This is only available on Android API 31 and above. Within the process, the handle are unique.

Returns

The system unique id if one can be obtained.

Definition at line 115 of file hardware_buffer.cc.

                             {
  if (!GetProcTable().AHardwareBuffer_getId) {
    return std::nullopt;
  }
  uint64_t out_id = 0u;
  if (GetProcTable().AHardwareBuffer_getId(buffer, &out_id) != 0) {
    return std::nullopt;
  }
  return out_id;
}

IsAvailableOnPlatform()

bool impeller::android::HardwareBuffer::IsAvailableOnPlatform ( )

static

Definition at line 107 of file hardware_buffer.cc.

                                           {
  return GetProcTable().IsValid() && GetProcTable().AHardwareBuffer_isSupported;
}

IsValid()

bool impeller::android::HardwareBuffer::IsValid

(

)

const

Definition at line 79 of file hardware_buffer.cc.

                                   {
  return is_valid_;
}

Lock()

void * impeller::android::HardwareBuffer::Lock

(

CPUAccessType

type

)

const

Lock the buffer for CPU access. This call may fail if the buffer was not created with one the usages that allow for CPU access.

Parameters

[in]

type

The type

Returns

A host-accessible buffer if there was no error related to usage or buffer validity.

Definition at line 137 of file hardware_buffer.cc.

                                                   {
  if (!is_valid_ || !GetProcTable().AHardwareBuffer_lock) {
    return nullptr;
  }
  uint64_t usage = 0;
  switch (type) {
    case CPUAccessType::kRead:
      usage |= AHARDWAREBUFFER_USAGE_CPU_READ_MASK;
      break;
    case CPUAccessType::kWrite:
      usage |= AHARDWAREBUFFER_USAGE_CPU_WRITE_MASK;
      break;
  }
  void* buffer = nullptr;
  const auto result = GetProcTable().AHardwareBuffer_lock(  //
      buffer_.get(),                                        // buffer
      usage,                                                // usage
      -1,                                                   // fence
      nullptr,                                              // rect
      &buffer                                               // out-addr
  );
  return result == 0 ? buffer : nullptr;
}

operator=()

HardwareBuffer & impeller::android::HardwareBuffer::operator= ( const HardwareBuffer &  )

delete

Unlock()

bool impeller::android::HardwareBuffer::Unlock

(

)

const

Unlock a mapping previously locked for CPU access.

Returns

If the unlock was successful.

Definition at line 161 of file hardware_buffer.cc.

                                  {
  if (!is_valid_ || !GetProcTable().AHardwareBuffer_unlock) {
    return false;
  }
  const auto result =
      GetProcTable().AHardwareBuffer_unlock(buffer_.get(), nullptr);
  return result == 0;
}

---

The documentation for this class was generated from the following files:

• impeller/toolkit/android/hardware_buffer.h
• impeller/toolkit/android/hardware_buffer.cc