84674909a2
This PR is for resolving the following issue: [issue](https://github.com/capnproto/pycapnp/issues/379) 1. Created `_PyCustomMessageBuilder` extends `MessageBuilder`, enabling the ability to customise the `SegmentAllocate` method in Python. This allows allocation and data population within shared memory, and supports zero-copy inter-process data transfer by passing segment offsets. 2. Fields of type `Data` now support being set with a `memoryview`. When retrieving a `Data` field from a `DynamicStructBuilder`, it will return a writable `memoryview`, allowing users to modify the data directly. This enables memory to be pre-allocated and content to be modified in later, eliminating an extra copy. When retrieving a `Data` field from a `DynamicStructReader`, it will return a read-only `memoryview`, allowing user to read data without memory copy. * add memoryview and custom builder * support set dynamic field * add curSize * add initialSize and lastSize * change StringPtr name * add test case * refine test case * convert func to py callable object * add initial value * refine example * add copy as_reader and new_message, make structReader's data field return RO memoryView * rebase master and bugfix * reformat flake8 * refine test case * refine test cases for blob * remove unused import for flake8 * run black . --------- Co-authored-by: Brian Xu <brian.xu1@bytedance.com>
29 lines
604 B
C++
29 lines
604 B
C++
#pragma once
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#include "Python.h"
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#include <capnp/message.h>
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#include <capnp/serialize.h>
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#include <vector>
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namespace capnp {
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class PyCustomMessageBuilder : public capnp::MessageBuilder {
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public:
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explicit PyCustomMessageBuilder(PyObject* allocateSegmentCallable,
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uint firstSegmentWords = capnp::SUGGESTED_FIRST_SEGMENT_WORDS);
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~PyCustomMessageBuilder() noexcept(false) override;
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kj::ArrayPtr<capnp::word> allocateSegment(capnp::uint minimumSize) override;
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private:
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PyObject* allocateSegmentCallable;
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uint firstSize;
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uint curSize = 0;
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std::vector<PyObject*> allocatedBuffers;
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};
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}
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