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#include "compression.hh"
#include "util.hh"
#include "finally.hh"
#include <lzma.h>
#include <bzlib.h>
#include <cstdio>
#include <cstring>
#include <iostream>
namespace nix {
static ref<std::string> decompressXZ(const std::string & in)
{
lzma_stream strm(LZMA_STREAM_INIT);
lzma_ret ret = lzma_stream_decoder(
&strm, UINT64_MAX, LZMA_CONCATENATED);
if (ret != LZMA_OK)
throw Error("unable to initialise lzma decoder");
Finally free([&]() { lzma_end(&strm); });
lzma_action action = LZMA_RUN;
uint8_t outbuf[BUFSIZ];
ref<std::string> res = make_ref<std::string>();
strm.next_in = (uint8_t *) in.c_str();
strm.avail_in = in.size();
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
while (true) {
checkInterrupt();
if (strm.avail_in == 0)
action = LZMA_FINISH;
lzma_ret ret = lzma_code(&strm, action);
if (strm.avail_out == 0 || ret == LZMA_STREAM_END) {
res->append((char *) outbuf, sizeof(outbuf) - strm.avail_out);
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
if (ret == LZMA_STREAM_END)
return res;
if (ret != LZMA_OK)
throw Error("error while decompressing xz file");
}
}
static ref<std::string> decompressBzip2(const std::string & in)
{
bz_stream strm;
memset(&strm, 0, sizeof(strm));
int ret = BZ2_bzDecompressInit(&strm, 0, 0);
if (ret != BZ_OK)
throw Error("unable to initialise bzip2 decoder");
Finally free([&]() { BZ2_bzDecompressEnd(&strm); });
char outbuf[BUFSIZ];
ref<std::string> res = make_ref<std::string>();
strm.next_in = (char *) in.c_str();
strm.avail_in = in.size();
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
while (true) {
checkInterrupt();
int ret = BZ2_bzDecompress(&strm);
if (strm.avail_out == 0 || ret == BZ_STREAM_END) {
res->append(outbuf, sizeof(outbuf) - strm.avail_out);
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
if (ret == BZ_STREAM_END)
return res;
if (ret != BZ_OK)
throw Error("error while decompressing bzip2 file");
}
}
static ref<std::string> decompressBrotli(const std::string & in)
{
return make_ref<std::string>(runProgram(BRO, true, {"-d"}, in));
}
ref<std::string> compress(const std::string & method, const std::string & in)
{
StringSink ssink;
auto sink = makeCompressionSink(method, ssink);
(*sink)(in);
sink->finish();
return ssink.s;
}
ref<std::string> decompress(const std::string & method, const std::string & in)
{
if (method == "none")
return make_ref<std::string>(in);
else if (method == "xz")
return decompressXZ(in);
else if (method == "bzip2")
return decompressBzip2(in);
else if (method == "br")
return decompressBrotli(in);
else
throw UnknownCompressionMethod(format("unknown compression method ‘%s’") % method);
}
struct NoneSink : CompressionSink
{
Sink & nextSink;
NoneSink(Sink & nextSink) : nextSink(nextSink) { }
void finish() override { flush(); }
void write(const unsigned char * data, size_t len) override { nextSink(data, len); }
};
struct XzSink : CompressionSink
{
Sink & nextSink;
uint8_t outbuf[BUFSIZ];
lzma_stream strm = LZMA_STREAM_INIT;
bool finished = false;
XzSink(Sink & nextSink) : nextSink(nextSink)
{
lzma_ret ret = lzma_easy_encoder(
&strm, 6, LZMA_CHECK_CRC64);
if (ret != LZMA_OK)
throw Error("unable to initialise lzma encoder");
// FIXME: apply the x86 BCJ filter?
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
~XzSink()
{
lzma_end(&strm);
}
void finish() override
{
CompressionSink::flush();
assert(!finished);
finished = true;
while (true) {
checkInterrupt();
lzma_ret ret = lzma_code(&strm, LZMA_FINISH);
if (ret != LZMA_OK && ret != LZMA_STREAM_END)
throw Error("error while flushing xz file");
if (strm.avail_out == 0 || ret == LZMA_STREAM_END) {
nextSink(outbuf, sizeof(outbuf) - strm.avail_out);
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
if (ret == LZMA_STREAM_END) break;
}
}
void write(const unsigned char * data, size_t len) override
{
assert(!finished);
strm.next_in = data;
strm.avail_in = len;
while (strm.avail_in) {
checkInterrupt();
lzma_ret ret = lzma_code(&strm, LZMA_RUN);
if (ret != LZMA_OK)
throw Error("error while compressing xz file");
if (strm.avail_out == 0) {
nextSink(outbuf, sizeof(outbuf));
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
}
}
};
struct BzipSink : CompressionSink
{
Sink & nextSink;
char outbuf[BUFSIZ];
bz_stream strm;
bool finished = false;
BzipSink(Sink & nextSink) : nextSink(nextSink)
{
memset(&strm, 0, sizeof(strm));
int ret = BZ2_bzCompressInit(&strm, 9, 0, 30);
if (ret != BZ_OK)
throw Error("unable to initialise bzip2 encoder");
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
~BzipSink()
{
BZ2_bzCompressEnd(&strm);
}
void finish() override
{
flush();
assert(!finished);
finished = true;
while (true) {
checkInterrupt();
int ret = BZ2_bzCompress(&strm, BZ_FINISH);
if (ret != BZ_FINISH_OK && ret != BZ_STREAM_END)
throw Error("error while flushing bzip2 file");
if (strm.avail_out == 0 || ret == BZ_STREAM_END) {
nextSink((unsigned char *) outbuf, sizeof(outbuf) - strm.avail_out);
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
if (ret == BZ_STREAM_END) break;
}
}
void write(const unsigned char * data, size_t len) override
{
assert(!finished);
strm.next_in = (char *) data;
strm.avail_in = len;
while (strm.avail_in) {
checkInterrupt();
int ret = BZ2_bzCompress(&strm, BZ_RUN);
if (ret != BZ_OK)
Error("error while compressing bzip2 file");
if (strm.avail_out == 0) {
nextSink((unsigned char *) outbuf, sizeof(outbuf));
strm.next_out = outbuf;
strm.avail_out = sizeof(outbuf);
}
}
}
};
ref<CompressionSink> makeCompressionSink(const std::string & method, Sink & nextSink)
{
if (method == "none")
return make_ref<NoneSink>(nextSink);
else if (method == "xz")
return make_ref<XzSink>(nextSink);
else if (method == "bzip2")
return make_ref<BzipSink>(nextSink);
else
throw UnknownCompressionMethod(format("unknown compression method ‘%s’") % method);
}
}
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