| // Copyright 2015 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef LIBCHROMEOS_CHROMEOS_STREAMS_MEMORY_CONTAINERS_H_ |
| #define LIBCHROMEOS_CHROMEOS_STREAMS_MEMORY_CONTAINERS_H_ |
| |
| #include <string> |
| #include <vector> |
| |
| #include <chromeos/chromeos_export.h> |
| #include <chromeos/errors/error.h> |
| #include <chromeos/streams/stream.h> |
| |
| namespace chromeos { |
| namespace data_container { |
| |
| // MemoryStream class relies on helper classes defined below to support data |
| // storage in various types of containers. |
| // A particular implementation of container type (e.g. based on raw memory |
| // buffers, std::vector, std::string or others) need to implement the container |
| // interface provided by data_container::DataContainerInterface. |
| // Low-level functionality such as reading data from and writing data to the |
| // container, getting and changing the buffer size, and so on, must be provided. |
| // Not all methods must be provided. For example, for read-only containers, only |
| // read operations can be provided. |
| class CHROMEOS_EXPORT DataContainerInterface { |
| public: |
| DataContainerInterface() = default; |
| virtual ~DataContainerInterface() = default; |
| |
| // Read the data from the container into |buffer|. Up to |size_to_read| bytes |
| // must be read at a time. The container can return fewer bytes. The actual |
| // size of data read is provided in |size_read|. |
| // If the read operation fails, the function must return false and provide |
| // additional information about the error in |error| object. |
| virtual bool Read(void* buffer, |
| size_t size_to_read, |
| size_t offset, |
| size_t* size_read, |
| ErrorPtr* error) = 0; |
| |
| // Writes |size_to_write| bytes of data from |buffer| into the container. |
| // The container may accept fewer bytes of data. The actual size of data |
| // written is provided in |size_written|. |
| // If the read operation fails, the function must return false and provide |
| // additional information about the error in |error| object. |
| virtual bool Write(const void* buffer, |
| size_t size_to_write, |
| size_t offset, |
| size_t* size_written, |
| ErrorPtr* error) = 0; |
| // Resizes the container to the new size specified in |new_size|. |
| virtual bool Resize(size_t new_size, ErrorPtr* error) = 0; |
| // Returns the current size of the container. |
| virtual size_t GetSize() const = 0; |
| // Returns true if the container is read-only. |
| virtual bool IsReadOnly() const = 0; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(DataContainerInterface); |
| }; |
| |
| // ContiguousBufferBase is a helper base class for memory containers that |
| // employ contiguous memory for all of their data. This class provides the |
| // default implementation for Read() and Write() functions and requires the |
| // implementations to provide GetBuffer() and/or ReadOnlyBuffer() functions. |
| class CHROMEOS_EXPORT ContiguousBufferBase : public DataContainerInterface { |
| public: |
| ContiguousBufferBase() = default; |
| // Implementation of DataContainerInterface::Read(). |
| bool Read(void* buffer, |
| size_t size_to_read, |
| size_t offset, |
| size_t* size_read, |
| ErrorPtr* error) override; |
| // Implementation of DataContainerInterface::Write(). |
| bool Write(const void* buffer, |
| size_t size_to_write, |
| size_t offset, |
| size_t* size_written, |
| ErrorPtr* error) override; |
| |
| // Overload to provide the pointer to the read-only data for the container at |
| // the specified |offset|. In case of an error, this function must return |
| // nullptr and provide error details in |error| object if provided. |
| virtual const void* GetReadOnlyBuffer(size_t offset, |
| ErrorPtr* error) const = 0; |
| // Overload to provide the pointer to the read/write data for the container at |
| // the specified |offset|. In case of an error, this function must return |
| // nullptr and provide error details in |error| object if provided. |
| virtual void* GetBuffer(size_t offset, ErrorPtr* error) = 0; |
| |
| protected: |
| // Wrapper around memcpy which can be mocked out in tests. |
| virtual void CopyMemoryBlock(void* dest, const void* src, size_t size) const; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ContiguousBufferBase); |
| }; |
| |
| // ContiguousReadOnlyBufferBase is a specialization of ContiguousBufferBase for |
| // read-only containers. |
| class CHROMEOS_EXPORT ContiguousReadOnlyBufferBase |
| : public ContiguousBufferBase { |
| public: |
| ContiguousReadOnlyBufferBase() = default; |
| // Fails with an error "operation_not_supported" (Stream is read-only) error. |
| bool Write(const void* buffer, |
| size_t size_to_write, |
| size_t offset, |
| size_t* size_written, |
| ErrorPtr* error) override; |
| // Fails with an error "operation_not_supported" (Stream is read-only) error. |
| bool Resize(size_t new_size, ErrorPtr* error) override; |
| // Fails with an error "operation_not_supported" (Stream is read-only) error. |
| bool IsReadOnly() const override { return true; } |
| // Fails with an error "operation_not_supported" (Stream is read-only) error. |
| void* GetBuffer(size_t offset, ErrorPtr* error) override; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ContiguousReadOnlyBufferBase); |
| }; |
| |
| // ReadOnlyBuffer implements a read-only container based on raw memory block. |
| class CHROMEOS_EXPORT ReadOnlyBuffer : public ContiguousReadOnlyBufferBase { |
| public: |
| // Constructs the container based at the pointer to memory |buffer| and its |
| // |size|. The pointer to the memory must be valid throughout life-time of |
| // the stream using this container. |
| ReadOnlyBuffer(const void* buffer, size_t size) |
| : buffer_(buffer), size_(size) {} |
| |
| // Returns the pointer to data at |offset|. |
| const void* GetReadOnlyBuffer(size_t offset, ErrorPtr* error) const override { |
| return reinterpret_cast<const uint8_t*>(buffer_) + offset; |
| } |
| // Returns the size of the container. |
| size_t GetSize() const override { return size_; } |
| |
| private: |
| // Raw memory pointer to the data block and its size. |
| const void* buffer_; |
| size_t size_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ReadOnlyBuffer); |
| }; |
| |
| // VectorPtr<T> is a read/write container based on a vector<T> pointer. |
| // This is a template class to allow usage of both vector<char> and |
| // vector<uint8_t> without duplicating the implementation. |
| template<typename T> |
| class VectorPtr : public ContiguousBufferBase { |
| public: |
| static_assert(sizeof(T) == 1, "Only char/byte is supported"); |
| explicit VectorPtr(std::vector<T>* vector) : vector_ptr_(vector) {} |
| |
| bool Resize(size_t new_size, ErrorPtr* error) override { |
| vector_ptr_->resize(new_size); |
| return true; |
| } |
| size_t GetSize() const override { return vector_ptr_->size(); } |
| bool IsReadOnly() const override { return false; } |
| const void* GetReadOnlyBuffer(size_t offset, ErrorPtr* error) const override { |
| return reinterpret_cast<const uint8_t*>(vector_ptr_->data()) + offset; |
| } |
| void* GetBuffer(size_t offset, ErrorPtr* error) override { |
| return reinterpret_cast<uint8_t*>(vector_ptr_->data()) + offset; |
| } |
| |
| protected: |
| std::vector<T>* vector_ptr_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(VectorPtr); |
| }; |
| |
| // ReadOnlyVectorRef<T> is a read-only container based on a vector<T> reference. |
| // This is a template class to allow usage of both vector<char> and |
| // vector<uint8_t> without duplicating the implementation. |
| template<typename T> |
| class ReadOnlyVectorRef : public ContiguousReadOnlyBufferBase { |
| public: |
| static_assert(sizeof(T) == 1, "Only char/byte is supported"); |
| explicit ReadOnlyVectorRef(const std::vector<T>& vector) |
| : vector_ref_(vector) {} |
| |
| const void* GetReadOnlyBuffer(size_t offset, ErrorPtr* error) const override { |
| return reinterpret_cast<const uint8_t*>(vector_ref_.data()) + offset; |
| } |
| size_t GetSize() const override { return vector_ref_.size(); } |
| |
| protected: |
| const std::vector<T>& vector_ref_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ReadOnlyVectorRef); |
| }; |
| |
| // ReadOnlyVectorCopy<T> is a read-only container based on a copy of vector<T>. |
| // This container actually owns the data stored in the vector. |
| // This is a template class to allow usage of both vector<char> and |
| // vector<uint8_t> without duplicating the implementation. |
| template<typename T> |
| class ReadOnlyVectorCopy : public ContiguousReadOnlyBufferBase { |
| public: |
| static_assert(sizeof(T) == 1, "Only char/byte is supported"); |
| explicit ReadOnlyVectorCopy(std::vector<T> vector) |
| : vector_copy_(std::move(vector)) {} |
| |
| ReadOnlyVectorCopy(const T* buffer, size_t size) |
| : vector_copy_(buffer, buffer + size) {} |
| |
| const void* GetReadOnlyBuffer(size_t offset, ErrorPtr* error) const override { |
| return reinterpret_cast<const uint8_t*>(vector_copy_.data()) + offset; |
| } |
| size_t GetSize() const override { return vector_copy_.size(); } |
| |
| protected: |
| std::vector<T> vector_copy_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ReadOnlyVectorCopy); |
| }; |
| |
| // ByteBuffer is a read/write container that manages the data and underlying |
| // storage. |
| class CHROMEOS_EXPORT ByteBuffer : public VectorPtr<uint8_t> { |
| public: |
| explicit ByteBuffer(size_t reserve_size); |
| ~ByteBuffer() override; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ByteBuffer); |
| }; |
| |
| // StringPtr is a read/write container based on external std::string storage. |
| class CHROMEOS_EXPORT StringPtr : public ContiguousBufferBase { |
| public: |
| explicit StringPtr(std::string* string); |
| |
| bool Resize(size_t new_size, ErrorPtr* error) override; |
| size_t GetSize() const override { return string_ptr_->size(); } |
| bool IsReadOnly() const override { return false; } |
| const void* GetReadOnlyBuffer(size_t offset, ErrorPtr* error) const override; |
| void* GetBuffer(size_t offset, ErrorPtr* error) override; |
| |
| protected: |
| std::string* string_ptr_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(StringPtr); |
| }; |
| |
| // ReadOnlyStringRef is a read-only container based on external std::string. |
| class CHROMEOS_EXPORT ReadOnlyStringRef : public ContiguousReadOnlyBufferBase { |
| public: |
| explicit ReadOnlyStringRef(const std::string& string); |
| const void* GetReadOnlyBuffer(size_t offset, ErrorPtr* error) const override; |
| size_t GetSize() const override { return string_ref_.size(); } |
| |
| protected: |
| const std::string& string_ref_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ReadOnlyStringRef); |
| }; |
| |
| // ReadOnlyStringCopy is a read-only container based on a copy of a std::string. |
| // This container actually owns the data stored in the string. |
| class CHROMEOS_EXPORT ReadOnlyStringCopy : public ReadOnlyStringRef { |
| public: |
| explicit ReadOnlyStringCopy(std::string string); |
| |
| protected: |
| std::string string_copy_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(ReadOnlyStringCopy); |
| }; |
| |
| } // namespace data_container |
| } // namespace chromeos |
| |
| #endif // LIBCHROMEOS_CHROMEOS_STREAMS_MEMORY_CONTAINERS_H_ |