294 lines
9.1 KiB
C++
294 lines
9.1 KiB
C++
#include "compression.hh"
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#include "signals.hh"
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#include "tarfile.hh"
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#include "finally.hh"
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#include "logging.hh"
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#include <archive.h>
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#include <archive_entry.h>
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#include <cstdio>
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#include <cstring>
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#include <brotli/decode.h>
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#include <brotli/encode.h>
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#include <iostream>
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namespace nix {
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static const int COMPRESSION_LEVEL_DEFAULT = -1;
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// Don't feed brotli too much at once.
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struct ChunkedCompressionSink : CompressionSink
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{
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uint8_t outbuf[32 * 1024];
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void writeUnbuffered(std::string_view data) override
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{
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const size_t CHUNK_SIZE = sizeof(outbuf) << 2;
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while (!data.empty()) {
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size_t n = std::min(CHUNK_SIZE, data.size());
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writeInternal(data.substr(0, n));
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data.remove_prefix(n);
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}
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}
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virtual void writeInternal(std::string_view data) = 0;
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};
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struct ArchiveDecompressionSource : Source
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{
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std::unique_ptr<TarArchive> archive = 0;
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Source & src;
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ArchiveDecompressionSource(Source & src) : src(src) {}
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~ArchiveDecompressionSource() override {}
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size_t read(char * data, size_t len) override {
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struct archive_entry * ae;
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if (!archive) {
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archive = std::make_unique<TarArchive>(src, true);
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this->archive->check(archive_read_next_header(this->archive->archive, &ae),
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"failed to read header (%s)");
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if (archive_filter_count(this->archive->archive) < 2) {
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throw CompressionError("input compression not recognized");
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}
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}
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ssize_t result = archive_read_data(this->archive->archive, data, len);
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if (result > 0) return result;
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if (result == 0) {
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throw EndOfFile("reached end of compressed file");
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}
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this->archive->check(result, "failed to read compressed data (%s)");
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return result;
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}
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};
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struct ArchiveCompressionSink : CompressionSink
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{
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Sink & nextSink;
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struct archive * archive;
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ArchiveCompressionSink(Sink & nextSink, std::string format, bool parallel, int level = COMPRESSION_LEVEL_DEFAULT) : nextSink(nextSink)
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{
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archive = archive_write_new();
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if (!archive) throw Error("failed to initialize libarchive");
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check(archive_write_add_filter_by_name(archive, format.c_str()), "couldn't initialize compression (%s)");
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check(archive_write_set_format_raw(archive));
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if (parallel)
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check(archive_write_set_filter_option(archive, format.c_str(), "threads", "0"));
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if (level != COMPRESSION_LEVEL_DEFAULT)
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check(archive_write_set_filter_option(archive, format.c_str(), "compression-level", std::to_string(level).c_str()));
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// disable internal buffering
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check(archive_write_set_bytes_per_block(archive, 0));
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// disable output padding
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check(archive_write_set_bytes_in_last_block(archive, 1));
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open();
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}
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~ArchiveCompressionSink() override
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{
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if (archive) archive_write_free(archive);
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}
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void finish() override
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{
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flush();
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check(archive_write_close(archive));
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}
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void check(int err, const std::string & reason = "failed to compress (%s)")
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{
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if (err == ARCHIVE_EOF)
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throw EndOfFile("reached end of archive");
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else if (err != ARCHIVE_OK)
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throw Error(reason, archive_error_string(this->archive));
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}
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void writeUnbuffered(std::string_view data) override
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{
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ssize_t result = archive_write_data(archive, data.data(), data.length());
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if (result <= 0) check(result);
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}
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private:
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void open()
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{
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check(archive_write_open(archive, this, nullptr, ArchiveCompressionSink::callback_write, nullptr));
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auto ae = archive_entry_new();
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archive_entry_set_filetype(ae, AE_IFREG);
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check(archive_write_header(archive, ae));
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archive_entry_free(ae);
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}
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static ssize_t callback_write(struct archive * archive, void * _self, const void * buffer, size_t length)
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{
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auto self = (ArchiveCompressionSink *) _self;
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self->nextSink({(const char *) buffer, length});
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return length;
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}
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};
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struct NoneSink : CompressionSink
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{
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Sink & nextSink;
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NoneSink(Sink & nextSink, int level = COMPRESSION_LEVEL_DEFAULT) : nextSink(nextSink)
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{
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if (level != COMPRESSION_LEVEL_DEFAULT)
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warn("requested compression level '%d' not supported by compression method 'none'", level);
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}
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void finish() override { flush(); }
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void writeUnbuffered(std::string_view data) override { nextSink(data); }
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};
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struct BrotliDecompressionSink : ChunkedCompressionSink
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{
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Sink & nextSink;
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BrotliDecoderState * state;
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bool finished = false;
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BrotliDecompressionSink(Sink & nextSink) : nextSink(nextSink)
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{
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state = BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);
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if (!state)
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throw CompressionError("unable to initialize brotli decoder");
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}
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~BrotliDecompressionSink()
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{
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BrotliDecoderDestroyInstance(state);
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}
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void finish() override
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{
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flush();
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writeInternal({});
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}
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void writeInternal(std::string_view data) override
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{
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auto next_in = (const uint8_t *) data.data();
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size_t avail_in = data.size();
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uint8_t * next_out = outbuf;
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size_t avail_out = sizeof(outbuf);
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while (!finished && (!data.data() || avail_in)) {
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checkInterrupt();
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if (!BrotliDecoderDecompressStream(state,
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&avail_in, &next_in,
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&avail_out, &next_out,
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nullptr))
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throw CompressionError("error while decompressing brotli file");
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if (avail_out < sizeof(outbuf) || avail_in == 0) {
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nextSink({(char *) outbuf, sizeof(outbuf) - avail_out});
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next_out = outbuf;
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avail_out = sizeof(outbuf);
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}
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finished = BrotliDecoderIsFinished(state);
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}
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}
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};
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std::string decompress(const std::string & method, std::string_view in)
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{
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StringSink ssink;
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auto sink = makeDecompressionSink(method, ssink);
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(*sink)(in);
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sink->finish();
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return std::move(ssink.s);
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}
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std::unique_ptr<FinishSink> makeDecompressionSink(const std::string & method, Sink & nextSink)
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{
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if (method == "none" || method == "")
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return std::make_unique<NoneSink>(nextSink);
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else if (method == "br")
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return std::make_unique<BrotliDecompressionSink>(nextSink);
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else
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return sourceToSink([&](Source & source) {
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auto decompressionSource = std::make_unique<ArchiveDecompressionSource>(source);
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decompressionSource->drainInto(nextSink);
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});
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}
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struct BrotliCompressionSink : ChunkedCompressionSink
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{
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Sink & nextSink;
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uint8_t outbuf[BUFSIZ];
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BrotliEncoderState * state;
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bool finished = false;
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BrotliCompressionSink(Sink & nextSink) : nextSink(nextSink)
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{
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state = BrotliEncoderCreateInstance(nullptr, nullptr, nullptr);
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if (!state)
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throw CompressionError("unable to initialise brotli encoder");
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}
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~BrotliCompressionSink()
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{
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BrotliEncoderDestroyInstance(state);
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}
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void finish() override
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{
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flush();
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writeInternal({});
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}
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void writeInternal(std::string_view data) override
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{
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auto next_in = (const uint8_t *) data.data();
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size_t avail_in = data.size();
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uint8_t * next_out = outbuf;
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size_t avail_out = sizeof(outbuf);
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while (!finished && (!data.data() || avail_in)) {
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checkInterrupt();
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if (!BrotliEncoderCompressStream(state,
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data.data() ? BROTLI_OPERATION_PROCESS : BROTLI_OPERATION_FINISH,
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&avail_in, &next_in,
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&avail_out, &next_out,
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nullptr))
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throw CompressionError("error while compressing brotli compression");
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if (avail_out < sizeof(outbuf) || avail_in == 0) {
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nextSink({(const char *) outbuf, sizeof(outbuf) - avail_out});
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next_out = outbuf;
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avail_out = sizeof(outbuf);
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}
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finished = BrotliEncoderIsFinished(state);
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}
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}
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};
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ref<CompressionSink> makeCompressionSink(const std::string & method, Sink & nextSink, const bool parallel, int level)
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{
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std::vector<std::string> la_supports = {
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"bzip2", "compress", "grzip", "gzip", "lrzip", "lz4", "lzip", "lzma", "lzop", "xz", "zstd"
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};
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if (std::find(la_supports.begin(), la_supports.end(), method) != la_supports.end()) {
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return make_ref<ArchiveCompressionSink>(nextSink, method, parallel, level);
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}
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if (method == "none")
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return make_ref<NoneSink>(nextSink);
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else if (method == "br")
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return make_ref<BrotliCompressionSink>(nextSink);
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else
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throw UnknownCompressionMethod("unknown compression method '%s'", method);
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}
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std::string compress(const std::string & method, std::string_view in, const bool parallel, int level)
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{
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StringSink ssink;
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auto sink = makeCompressionSink(method, ssink, parallel, level);
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(*sink)(in);
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sink->finish();
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return std::move(ssink.s);
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}
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}
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