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![Jonathan Tan](/assets/img/avatar_default.png)
Currently, a response to a fetch request has sideband support only while the packfile is being sent, meaning that the server cannot send notices until the start of the packfile. Extend sideband support in protocol v2 fetch responses to the whole response. upload-pack will advertise it if the uploadpack.allowsidebandall configuration variable is set, and fetch-pack will automatically request it if advertised. If the sideband is to be used throughout the whole response, upload-pack will use it to send errors instead of prefixing a PKT-LINE payload with "ERR ". This will be tested in a subsequent patch. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
221 lines
7.9 KiB
C
221 lines
7.9 KiB
C
#ifndef PKTLINE_H
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#define PKTLINE_H
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#include "git-compat-util.h"
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#include "strbuf.h"
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#include "sideband.h"
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/*
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* Write a packetized stream, where each line is preceded by
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* its length (including the header) as a 4-byte hex number.
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* A length of 'zero' means end of stream (and a length of 1-3
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* would be an error).
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*
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* This is all pretty stupid, but we use this packetized line
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* format to make a streaming format possible without ever
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* over-running the read buffers. That way we'll never read
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* into what might be the pack data (which should go to another
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* process entirely).
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*
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* The writing side could use stdio, but since the reading
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* side can't, we stay with pure read/write interfaces.
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*/
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void packet_flush(int fd);
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void packet_delim(int fd);
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void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
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void packet_buf_flush(struct strbuf *buf);
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void packet_buf_delim(struct strbuf *buf);
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void packet_write(int fd_out, const char *buf, size_t size);
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void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
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void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
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int packet_flush_gently(int fd);
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int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
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int write_packetized_from_fd(int fd_in, int fd_out);
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int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);
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/*
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* Read a packetized line into the buffer, which must be at least size bytes
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* long. The return value specifies the number of bytes read into the buffer.
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*
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* If src_buffer and *src_buffer are not NULL, it should point to a buffer
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* containing the packet data to parse, of at least *src_len bytes. After the
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* function returns, src_buf will be incremented and src_len decremented by the
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* number of bytes consumed.
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*
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* If src_buffer (or *src_buffer) is NULL, then data is read from the
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* descriptor "fd".
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*
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* If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
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* of the following conditions:
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*
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* 1. Read error from descriptor.
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*
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* 2. Protocol error from the remote (e.g., bogus length characters).
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*
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* 3. Receiving a packet larger than "size" bytes.
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*
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* 4. Truncated output from the remote (e.g., we expected a packet but got
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* EOF, or we got a partial packet followed by EOF).
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*
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* If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
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* condition 4 (truncated input), but instead return -1. However, we will still
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* die for the other 3 conditions.
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*
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* If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
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* present) is removed from the buffer before returning.
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*
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* If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an
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* ERR packet.
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*/
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#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
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#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
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#define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2)
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int packet_read(int fd, char **src_buffer, size_t *src_len, char
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*buffer, unsigned size, int options);
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/*
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* Read a packetized line into a buffer like the 'packet_read()' function but
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* returns an 'enum packet_read_status' which indicates the status of the read.
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* The number of bytes read will be assigined to *pktlen if the status of the
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* read was 'PACKET_READ_NORMAL'.
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*/
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enum packet_read_status {
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PACKET_READ_EOF,
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PACKET_READ_NORMAL,
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PACKET_READ_FLUSH,
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PACKET_READ_DELIM,
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};
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enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
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size_t *src_len, char *buffer,
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unsigned size, int *pktlen,
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int options);
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/*
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* Convenience wrapper for packet_read that is not gentle, and sets the
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* CHOMP_NEWLINE option. The return value is NULL for a flush packet,
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* and otherwise points to a static buffer (that may be overwritten by
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* subsequent calls). If the size parameter is not NULL, the length of the
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* packet is written to it.
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*/
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char *packet_read_line(int fd, int *size);
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/*
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* Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF
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* and CHOMP_NEWLINE options. The return value specifies the number of bytes
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* read into the buffer or -1 on truncated input. If the *dst_line parameter
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* is not NULL it will return NULL for a flush packet or when the number of
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* bytes copied is zero and otherwise points to a static buffer (that may be
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* overwritten by subsequent calls). If the size parameter is not NULL, the
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* length of the packet is written to it.
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*/
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int packet_read_line_gently(int fd, int *size, char **dst_line);
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/*
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* Same as packet_read_line, but read from a buf rather than a descriptor;
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* see packet_read for details on how src_* is used.
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*/
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char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
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/*
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* Reads a stream of variable sized packets until a flush packet is detected.
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*/
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ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);
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/*
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* Receive multiplexed output stream over git native protocol.
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* in_stream is the input stream from the remote, which carries data
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* in pkt_line format with band designator. Demultiplex it into out
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* and err and return error appropriately. Band #1 carries the
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* primary payload. Things coming over band #2 is not necessarily
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* error; they are usually informative message on the standard error
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* stream, aka "verbose"). A message over band #3 is a signal that
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* the remote died unexpectedly. A flush() concludes the stream.
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*
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* Returns SIDEBAND_FLUSH upon a normal conclusion, and SIDEBAND_PROTOCOL_ERROR
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* or SIDEBAND_REMOTE_ERROR if an error occurred.
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*/
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int recv_sideband(const char *me, int in_stream, int out);
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struct packet_reader {
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/* source file descriptor */
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int fd;
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/* source buffer and its size */
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char *src_buffer;
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size_t src_len;
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/* buffer that pkt-lines are read into and its size */
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char *buffer;
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unsigned buffer_size;
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/* options to be used during reads */
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int options;
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/* status of the last read */
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enum packet_read_status status;
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/* length of data read during the last read */
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int pktlen;
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/* the last line read */
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const char *line;
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/* indicates if a line has been peeked */
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int line_peeked;
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unsigned use_sideband : 1;
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const char *me;
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};
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/*
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* Initialize a 'struct packet_reader' object which is an
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* abstraction around the 'packet_read_with_status()' function.
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*/
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extern void packet_reader_init(struct packet_reader *reader, int fd,
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char *src_buffer, size_t src_len,
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int options);
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/*
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* Perform a packet read and return the status of the read.
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* The values of 'pktlen' and 'line' are updated based on the status of the
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* read as follows:
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*
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* PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL
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* PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read
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* 'line' is set to point at the read line
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* PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL
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*/
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extern enum packet_read_status packet_reader_read(struct packet_reader *reader);
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/*
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* Peek the next packet line without consuming it and return the status.
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* The next call to 'packet_reader_read()' will perform a read of the same line
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* that was peeked, consuming the line.
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*
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* Peeking multiple times without calling 'packet_reader_read()' will return
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* the same result.
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*/
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extern enum packet_read_status packet_reader_peek(struct packet_reader *reader);
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#define DEFAULT_PACKET_MAX 1000
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#define LARGE_PACKET_MAX 65520
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#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
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extern char packet_buffer[LARGE_PACKET_MAX];
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struct packet_writer {
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int dest_fd;
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unsigned use_sideband : 1;
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};
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void packet_writer_init(struct packet_writer *writer, int dest_fd);
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/* These functions die upon failure. */
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__attribute__((format (printf, 2, 3)))
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void packet_writer_write(struct packet_writer *writer, const char *fmt, ...);
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__attribute__((format (printf, 2, 3)))
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void packet_writer_error(struct packet_writer *writer, const char *fmt, ...);
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void packet_writer_delim(struct packet_writer *writer);
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void packet_writer_flush(struct packet_writer *writer);
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#endif
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