| /* |
| * Copyright (C) 2024 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <fmq/AidlMessageQueue.h> |
| |
| using aidl::android::hardware::common::NativeHandle; |
| using aidl::android::hardware::common::fmq::GrantorDescriptor; |
| using aidl::android::hardware::common::fmq::SynchronizedReadWrite; |
| |
| using namespace android; |
| |
| struct MemTransaction { |
| MessageQueueBase<AidlMQDescriptorShim, MQErased, |
| FlavorTypeToValue<SynchronizedReadWrite>::value>::MemRegion first; |
| MessageQueueBase<AidlMQDescriptorShim, MQErased, |
| FlavorTypeToValue<SynchronizedReadWrite>::value>::MemRegion second; |
| }; |
| |
| typedef MQDescriptor<MQErased, SynchronizedReadWrite> ErasedMessageQueueDesc; |
| |
| GrantorDescriptor convertGrantor(int32_t fdIndex, int32_t offset, int64_t extent); |
| |
| /** |
| * Construct a C++ AIDL MQDescriptor<MQErased, SynchronizedReadWrite> (aka an |
| * ErasedMessageQueueDesc) from the fields of a Rust AIDL |
| * MQDescriptor<MQErased, SynchronizedReadWrite>. |
| * |
| * These two types are semantically equivalent but come from separate AIDL |
| * codegen backends, so we must convert between them. To convert in the opposite |
| * direction, use the descFoo methods to access each field, and manually build |
| * the Rust AIDL MQDescriptor<MQErased, SynchronizedReadWrite> instance; |
| * see the Rust MessageQueue<T>::dupe_desc method. |
| * |
| * @param grantors Pointer to the start of the MQDescriptor's GrantorDescriptor |
| * array. |
| * @param n_grantors The length of the MQDescriptor's GrantorDescriptor array. |
| * @param handle_fds Pointer to the start of the MQDescriptor's NativeHandle's |
| * file-descriptor array. Ownership of array and contents is not transferred. |
| * @param handle_n_fds The corresponding length. |
| * @param handle_ints Pointer to the start of the MQDescriptor's NativeHandle's |
| * integer array. Ownership of the array is not transferred. |
| * @param handle_n_ints The corresponding length. |
| * @param quantum The MQDescriptor's quantum. |
| * @param flags The MQDescriptor's flags. |
| * |
| * @return A heap-allocated ErasedMessageQueueDesc instance owned by the caller, |
| * which must be freed with freeDesc. |
| */ |
| ErasedMessageQueueDesc* convertDesc(const GrantorDescriptor* grantors, size_t n_grantors, |
| const int* handle_fds, size_t handle_n_fds, |
| const int32_t* handle_ints, size_t handle_n_ints, |
| int32_t quantum, int32_t flags); |
| |
| /** |
| * Free a heap-allocated ErasedMessageQueueDesc. Simply calls delete. |
| * |
| * @param desc The ErasedMessageQueueDesc to free. |
| */ |
| void freeDesc(ErasedMessageQueueDesc* desc); |
| |
| /** |
| * The following functions project out individual fields of an |
| * ErasedMessageQueueDesc as FFI-safe types to enable constructing a Rust AIDL |
| * MQDescriptor<MQErased, SynchronizedReadWrite> from a C++ AIDL one. See the |
| * Rust MessageQueue<T>::dupe_desc method. |
| */ |
| |
| const GrantorDescriptor* descGrantors(const ErasedMessageQueueDesc& desc); |
| size_t descNumGrantors(const ErasedMessageQueueDesc& desc); |
| const ndk::ScopedFileDescriptor* descHandleFDs(const ErasedMessageQueueDesc& desc); |
| size_t descHandleNumFDs(const ErasedMessageQueueDesc& desc); |
| const int* descHandleInts(const ErasedMessageQueueDesc& desc); |
| size_t descHandleNumInts(const ErasedMessageQueueDesc& desc); |
| int32_t descQuantum(const ErasedMessageQueueDesc& desc); |
| int32_t descFlags(const ErasedMessageQueueDesc& desc); |
| |
| /** |
| * ErasedMessageQueue is a monomorphized wrapper around AidlMessageQueue that lets |
| * us wrap it in an idiomatic Rust API. It does not statically know its element |
| * type, but treats elements as opaque objects whose size is given by the |
| * MQDescriptor. |
| */ |
| class ErasedMessageQueue { |
| /* This must be a unique_ptr because bindgen cannot handle by-value fields |
| * of template class type. */ |
| std::unique_ptr<AidlMessageQueue<MQErased, SynchronizedReadWrite>> inner; |
| |
| public: |
| ErasedMessageQueue(const ErasedMessageQueueDesc& desc, bool resetPointers = true); |
| ErasedMessageQueue(size_t numElementsInQueue, bool configureEventFlagWord, size_t quantum); |
| |
| /** |
| * Get a MemTransaction object to write `nMessages` elements. |
| * Once the write is performed using the information from MemTransaction, |
| * the write operation is to be committed using a call to commitWrite(). |
| * |
| * @param nMessages Number of messages of the element type. |
| * @param Pointer to MemTransaction struct that describes memory to write |
| * `nMessages` items of the element type. If a write of size `nMessages` is |
| * not possible, the base addresses in the `MemTransaction` object will be |
| * set to nullptr. |
| * |
| * @return Whether it is possible to write `nMessages` items into the FMQ. |
| */ |
| bool beginWrite(size_t nMessages, MemTransaction* memTx) const; |
| |
| /** |
| * Commit a write of size `nMessages`. To be only used after a call to |
| * `beginWrite()`. |
| * |
| * @param nMessages number of messages of the element type to be written. |
| * |
| * @return Whether the write operation of size `nMessages` succeeded. |
| */ |
| bool commitWrite(size_t nMessages); |
| |
| /** |
| * Get a MemTransaction object to read `nMessages` elements. |
| * Once the read is performed using the information from MemTransaction, |
| * the read operation is to be committed using a call to `commitRead()`. |
| * |
| * @param nMessages Number of messages of the element type. |
| * @param pointer to MemTransaction struct that describes memory to read |
| * `nMessages` items of the element type. If a read of size `nMessages` is |
| * not possible, the base pointers in the `MemTransaction` object returned |
| * will be set to nullptr. |
| * |
| * @return bool Whether it is possible to read `nMessages` items from the |
| * FMQ. |
| */ |
| bool beginRead(size_t nMessages, MemTransaction* memTx) const; |
| |
| /** |
| * Commit a read of size `nMessages`. To be only used after a call to |
| * `beginRead()`. |
| * |
| * @param nMessages number of messages of the element type to be read. |
| * |
| * @return bool Whether the read operation of size `nMessages` succeeded. |
| */ |
| bool commitRead(size_t nMessages); |
| |
| /** |
| * Create a copy of the MQDescriptor for this object. This descriptor can be |
| * sent over IPC to allow constructing a remote object that will access the |
| * same queue over shared memory. |
| * |
| * @return ErasedMessageQueueDesc The copied descriptor, which must be freed |
| * by passing it to freeDesc. |
| */ |
| ErasedMessageQueueDesc* dupeDesc(); |
| }; |