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annotate CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/kj/compat/readiness-io.h @ 69:33d812a61356

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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 17:55:14 -0400
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jpayne@69 1 // Copyright (c) 2016 Sandstorm Development Group, Inc. and contributors
jpayne@69 2 // Licensed under the MIT License:
jpayne@69 3 //
jpayne@69 4 // Permission is hereby granted, free of charge, to any person obtaining a copy
jpayne@69 5 // of this software and associated documentation files (the "Software"), to deal
jpayne@69 6 // in the Software without restriction, including without limitation the rights
jpayne@69 7 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
jpayne@69 8 // copies of the Software, and to permit persons to whom the Software is
jpayne@69 9 // furnished to do so, subject to the following conditions:
jpayne@69 10 //
jpayne@69 11 // The above copyright notice and this permission notice shall be included in
jpayne@69 12 // all copies or substantial portions of the Software.
jpayne@69 13 //
jpayne@69 14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
jpayne@69 15 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
jpayne@69 16 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
jpayne@69 17 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
jpayne@69 18 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
jpayne@69 19 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
jpayne@69 20 // THE SOFTWARE.
jpayne@69 21
jpayne@69 22 #pragma once
jpayne@69 23
jpayne@69 24 #include <kj/async-io.h>
jpayne@69 25
jpayne@69 26 KJ_BEGIN_HEADER
jpayne@69 27
jpayne@69 28 namespace kj {
jpayne@69 29
jpayne@69 30 class ReadyInputStreamWrapper {
jpayne@69 31 // Provides readiness-based Async I/O as a wrapper around KJ's standard completion-based API, for
jpayne@69 32 // compatibility with libraries that use readiness-based abstractions (e.g. OpenSSL).
jpayne@69 33 //
jpayne@69 34 // Unfortunately this requires buffering, so is not very efficient.
jpayne@69 35
jpayne@69 36 public:
jpayne@69 37 ReadyInputStreamWrapper(AsyncInputStream& input);
jpayne@69 38 ~ReadyInputStreamWrapper() noexcept(false);
jpayne@69 39 KJ_DISALLOW_COPY_AND_MOVE(ReadyInputStreamWrapper);
jpayne@69 40
jpayne@69 41 kj::Maybe<size_t> read(kj::ArrayPtr<byte> dst);
jpayne@69 42 // Reads bytes into `dst`, returning the number of bytes read. Returns zero only at EOF. Returns
jpayne@69 43 // nullptr if not ready.
jpayne@69 44
jpayne@69 45 kj::Promise<void> whenReady();
jpayne@69 46 // Returns a promise that resolves when read() will return non-null.
jpayne@69 47
jpayne@69 48 bool isAtEnd() { return eof; }
jpayne@69 49 // Returns true if read() would return zero.
jpayne@69 50
jpayne@69 51 private:
jpayne@69 52 AsyncInputStream& input;
jpayne@69 53 kj::ForkedPromise<void> pumpTask = nullptr;
jpayne@69 54 bool isPumping = false;
jpayne@69 55 bool eof = false;
jpayne@69 56
jpayne@69 57 kj::ArrayPtr<const byte> content = nullptr; // Points to currently-valid part of `buffer`.
jpayne@69 58 byte buffer[8192];
jpayne@69 59 };
jpayne@69 60
jpayne@69 61 class ReadyOutputStreamWrapper {
jpayne@69 62 // Provides readiness-based Async I/O as a wrapper around KJ's standard completion-based API, for
jpayne@69 63 // compatibility with libraries that use readiness-based abstractions (e.g. OpenSSL).
jpayne@69 64 //
jpayne@69 65 // Unfortunately this requires buffering, so is not very efficient.
jpayne@69 66
jpayne@69 67 public:
jpayne@69 68 ReadyOutputStreamWrapper(AsyncOutputStream& output);
jpayne@69 69 ~ReadyOutputStreamWrapper() noexcept(false);
jpayne@69 70 KJ_DISALLOW_COPY_AND_MOVE(ReadyOutputStreamWrapper);
jpayne@69 71
jpayne@69 72 kj::Maybe<size_t> write(kj::ArrayPtr<const byte> src);
jpayne@69 73 // Writes bytes from `src`, returning the number of bytes written. Never returns zero for
jpayne@69 74 // a non-empty `src`. Returns nullptr if not ready.
jpayne@69 75
jpayne@69 76 kj::Promise<void> whenReady();
jpayne@69 77 // Returns a promise that resolves when write() will return non-null.
jpayne@69 78
jpayne@69 79 class Cork;
jpayne@69 80 // An object that, when destructed, will uncork its parent stream.
jpayne@69 81
jpayne@69 82 Cork cork();
jpayne@69 83 // After calling, data won't be pumped until either the internal buffer fills up or the returned
jpayne@69 84 // object is destructed. Use this if you know multiple small write() calls will be happening in
jpayne@69 85 // the near future and want to flush them all at once.
jpayne@69 86 // Once the returned object is destructed, behavior goes back to normal. The returned object
jpayne@69 87 // must be destructed before the ReadyOutputStreamWrapper.
jpayne@69 88 // TODO(perf): This is an ugly hack to avoid sending lots of tiny packets when using TLS, which
jpayne@69 89 // has to work around OpenSSL's readiness-based I/O layer. We could certainly do better here.
jpayne@69 90
jpayne@69 91 private:
jpayne@69 92 AsyncOutputStream& output;
jpayne@69 93 ArrayPtr<const byte> segments[2];
jpayne@69 94 kj::ForkedPromise<void> pumpTask = nullptr;
jpayne@69 95 bool isPumping = false;
jpayne@69 96 bool corked = false;
jpayne@69 97
jpayne@69 98 uint start = 0; // index of first byte
jpayne@69 99 uint filled = 0; // number of bytes currently in buffer
jpayne@69 100
jpayne@69 101 byte buffer[8192];
jpayne@69 102
jpayne@69 103 void uncork();
jpayne@69 104
jpayne@69 105 kj::Promise<void> pump();
jpayne@69 106 // Asynchronously push the buffer out to the underlying stream.
jpayne@69 107 };
jpayne@69 108
jpayne@69 109 class ReadyOutputStreamWrapper::Cork {
jpayne@69 110 // An object that, when destructed, will uncork its parent stream.
jpayne@69 111 public:
jpayne@69 112 ~Cork() {
jpayne@69 113 KJ_IF_MAYBE(p, parent) {
jpayne@69 114 p->uncork();
jpayne@69 115 }
jpayne@69 116 }
jpayne@69 117 Cork(Cork&& other) : parent(kj::mv(other.parent)) {
jpayne@69 118 other.parent = nullptr;
jpayne@69 119 }
jpayne@69 120 KJ_DISALLOW_COPY(Cork);
jpayne@69 121
jpayne@69 122 private:
jpayne@69 123 Cork(ReadyOutputStreamWrapper& parent) : parent(parent) {}
jpayne@69 124
jpayne@69 125 kj::Maybe<ReadyOutputStreamWrapper&> parent;
jpayne@69 126 friend class ReadyOutputStreamWrapper;
jpayne@69 127 };
jpayne@69 128
jpayne@69 129 } // namespace kj
jpayne@69 130
jpayne@69 131 KJ_END_HEADER