180 lines
4.2 KiB
C++
180 lines
4.2 KiB
C++
#pragma once
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#include <memory>
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#include "types.hh"
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#include "util.hh"
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namespace nix {
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/* Abstract destination of binary data. */
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struct Sink
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{
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virtual ~Sink() { }
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virtual void operator () (const unsigned char * data, size_t len) = 0;
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virtual bool good() { return true; }
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void operator () (const std::string & s)
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{
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(*this)((const unsigned char *) s.data(), s.size());
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}
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};
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/* A buffered abstract sink. */
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struct BufferedSink : Sink
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{
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size_t bufSize, bufPos;
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std::unique_ptr<unsigned char[]> buffer;
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BufferedSink(size_t bufSize = 32 * 1024)
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: bufSize(bufSize), bufPos(0), buffer(nullptr) { }
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void operator () (const unsigned char * data, size_t len) override;
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void operator () (const std::string & s)
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{
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Sink::operator()(s);
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}
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void flush();
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virtual void write(const unsigned char * data, size_t len) = 0;
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};
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/* Abstract source of binary data. */
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struct Source
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{
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virtual ~Source() { }
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/* Store exactly ‘len’ bytes in the buffer pointed to by ‘data’.
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It blocks until all the requested data is available, or throws
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an error if it is not going to be available. */
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void operator () (unsigned char * data, size_t len);
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/* Store up to ‘len’ in the buffer pointed to by ‘data’, and
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return the number of bytes stored. If blocks until at least
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one byte is available. */
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virtual size_t read(unsigned char * data, size_t len) = 0;
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virtual bool good() { return true; }
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};
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/* A buffered abstract source. */
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struct BufferedSource : Source
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{
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size_t bufSize, bufPosIn, bufPosOut;
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std::unique_ptr<unsigned char[]> buffer;
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BufferedSource(size_t bufSize = 32 * 1024)
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: bufSize(bufSize), bufPosIn(0), bufPosOut(0), buffer(nullptr) { }
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size_t read(unsigned char * data, size_t len) override;
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/* Underlying read call, to be overridden. */
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virtual size_t readUnbuffered(unsigned char * data, size_t len) = 0;
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bool hasData();
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};
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/* A sink that writes data to a file descriptor. */
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struct FdSink : BufferedSink
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{
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int fd;
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bool warn = false;
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size_t written = 0;
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FdSink() : fd(-1) { }
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FdSink(int fd) : fd(fd) { }
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FdSink(FdSink&&) = default;
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FdSink& operator=(FdSink&&) = default;
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~FdSink();
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void write(const unsigned char * data, size_t len) override;
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bool good() override;
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private:
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bool _good = true;
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};
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/* A source that reads data from a file descriptor. */
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struct FdSource : BufferedSource
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{
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int fd;
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size_t read = 0;
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FdSource() : fd(-1) { }
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FdSource(int fd) : fd(fd) { }
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size_t readUnbuffered(unsigned char * data, size_t len) override;
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bool good() override;
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private:
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bool _good = true;
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};
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/* A sink that writes data to a string. */
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struct StringSink : Sink
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{
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ref<std::string> s;
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StringSink() : s(make_ref<std::string>()) { };
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StringSink(ref<std::string> s) : s(s) { };
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void operator () (const unsigned char * data, size_t len) override;
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};
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/* A source that reads data from a string. */
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struct StringSource : Source
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{
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const string & s;
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size_t pos;
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StringSource(const string & _s) : s(_s), pos(0) { }
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size_t read(unsigned char * data, size_t len) override;
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};
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void writePadding(size_t len, Sink & sink);
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void writeString(const unsigned char * buf, size_t len, Sink & sink);
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inline Sink & operator << (Sink & sink, uint64_t n)
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{
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unsigned char buf[8];
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buf[0] = n & 0xff;
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buf[1] = (n >> 8) & 0xff;
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buf[2] = (n >> 16) & 0xff;
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buf[3] = (n >> 24) & 0xff;
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buf[4] = (n >> 32) & 0xff;
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buf[5] = (n >> 40) & 0xff;
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buf[6] = (n >> 48) & 0xff;
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buf[7] = (n >> 56) & 0xff;
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sink(buf, sizeof(buf));
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return sink;
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}
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Sink & operator << (Sink & sink, const string & s);
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Sink & operator << (Sink & sink, const Strings & s);
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Sink & operator << (Sink & sink, const StringSet & s);
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void readPadding(size_t len, Source & source);
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unsigned int readInt(Source & source);
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unsigned long long readLongLong(Source & source);
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size_t readString(unsigned char * buf, size_t max, Source & source);
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string readString(Source & source);
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template<class T> T readStrings(Source & source);
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Source & operator >> (Source & in, string & s);
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Source & operator >> (Source & in, unsigned int & n);
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MakeError(SerialisationError, Error)
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}
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