From 1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5 Mon Sep 17 00:00:00 2001 From: Vincent Ambo Date: Sat, 11 Jan 2020 23:36:56 +0000 Subject: Squashed 'third_party/git/' content from commit cb71568594 git-subtree-dir: third_party/git git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7 --- pkt-line.h | 221 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 221 insertions(+) create mode 100644 pkt-line.h (limited to 'pkt-line.h') diff --git a/pkt-line.h b/pkt-line.h new file mode 100644 index 000000000000..5c62015db4df --- /dev/null +++ b/pkt-line.h @@ -0,0 +1,221 @@ +#ifndef PKTLINE_H +#define PKTLINE_H + +#include "git-compat-util.h" +#include "strbuf.h" +#include "sideband.h" + +/* + * Write a packetized stream, where each line is preceded by + * its length (including the header) as a 4-byte hex number. + * A length of 'zero' means end of stream (and a length of 1-3 + * would be an error). + * + * This is all pretty stupid, but we use this packetized line + * format to make a streaming format possible without ever + * over-running the read buffers. That way we'll never read + * into what might be the pack data (which should go to another + * process entirely). + * + * The writing side could use stdio, but since the reading + * side can't, we stay with pure read/write interfaces. + */ +void packet_flush(int fd); +void packet_delim(int fd); +void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); +void packet_buf_flush(struct strbuf *buf); +void packet_buf_delim(struct strbuf *buf); +void set_packet_header(char *buf, int size); +void packet_write(int fd_out, const char *buf, size_t size); +void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3))); +void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len); +int packet_flush_gently(int fd); +int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); +int write_packetized_from_fd(int fd_in, int fd_out); +int write_packetized_from_buf(const char *src_in, size_t len, int fd_out); + +/* + * Read a packetized line into the buffer, which must be at least size bytes + * long. The return value specifies the number of bytes read into the buffer. + * + * If src_buffer and *src_buffer are not NULL, it should point to a buffer + * containing the packet data to parse, of at least *src_len bytes. After the + * function returns, src_buf will be incremented and src_len decremented by the + * number of bytes consumed. + * + * If src_buffer (or *src_buffer) is NULL, then data is read from the + * descriptor "fd". + * + * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any + * of the following conditions: + * + * 1. Read error from descriptor. + * + * 2. Protocol error from the remote (e.g., bogus length characters). + * + * 3. Receiving a packet larger than "size" bytes. + * + * 4. Truncated output from the remote (e.g., we expected a packet but got + * EOF, or we got a partial packet followed by EOF). + * + * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on + * condition 4 (truncated input), but instead return -1. However, we will still + * die for the other 3 conditions. + * + * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if + * present) is removed from the buffer before returning. + * + * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an + * ERR packet. + */ +#define PACKET_READ_GENTLE_ON_EOF (1u<<0) +#define PACKET_READ_CHOMP_NEWLINE (1u<<1) +#define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2) +int packet_read(int fd, char **src_buffer, size_t *src_len, char + *buffer, unsigned size, int options); + +/* + * Read a packetized line into a buffer like the 'packet_read()' function but + * returns an 'enum packet_read_status' which indicates the status of the read. + * The number of bytes read will be assigined to *pktlen if the status of the + * read was 'PACKET_READ_NORMAL'. + */ +enum packet_read_status { + PACKET_READ_EOF, + PACKET_READ_NORMAL, + PACKET_READ_FLUSH, + PACKET_READ_DELIM, +}; +enum packet_read_status packet_read_with_status(int fd, char **src_buffer, + size_t *src_len, char *buffer, + unsigned size, int *pktlen, + int options); + +/* + * Convenience wrapper for packet_read that is not gentle, and sets the + * CHOMP_NEWLINE option. The return value is NULL for a flush packet, + * and otherwise points to a static buffer (that may be overwritten by + * subsequent calls). If the size parameter is not NULL, the length of the + * packet is written to it. + */ +char *packet_read_line(int fd, int *size); + +/* + * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF + * and CHOMP_NEWLINE options. The return value specifies the number of bytes + * read into the buffer or -1 on truncated input. If the *dst_line parameter + * is not NULL it will return NULL for a flush packet or when the number of + * bytes copied is zero and otherwise points to a static buffer (that may be + * overwritten by subsequent calls). If the size parameter is not NULL, the + * length of the packet is written to it. + */ +int packet_read_line_gently(int fd, int *size, char **dst_line); + +/* + * Same as packet_read_line, but read from a buf rather than a descriptor; + * see packet_read for details on how src_* is used. + */ +char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size); + +/* + * Reads a stream of variable sized packets until a flush packet is detected. + */ +ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out); + +/* + * Receive multiplexed output stream over git native protocol. + * in_stream is the input stream from the remote, which carries data + * in pkt_line format with band designator. Demultiplex it into out + * and err and return error appropriately. Band #1 carries the + * primary payload. Things coming over band #2 is not necessarily + * error; they are usually informative message on the standard error + * stream, aka "verbose"). A message over band #3 is a signal that + * the remote died unexpectedly. A flush() concludes the stream. + * + * Returns SIDEBAND_FLUSH upon a normal conclusion, and SIDEBAND_PROTOCOL_ERROR + * or SIDEBAND_REMOTE_ERROR if an error occurred. + */ +int recv_sideband(const char *me, int in_stream, int out); + +struct packet_reader { + /* source file descriptor */ + int fd; + + /* source buffer and its size */ + char *src_buffer; + size_t src_len; + + /* buffer that pkt-lines are read into and its size */ + char *buffer; + unsigned buffer_size; + + /* options to be used during reads */ + int options; + + /* status of the last read */ + enum packet_read_status status; + + /* length of data read during the last read */ + int pktlen; + + /* the last line read */ + const char *line; + + /* indicates if a line has been peeked */ + int line_peeked; + + unsigned use_sideband : 1; + const char *me; +}; + +/* + * Initialize a 'struct packet_reader' object which is an + * abstraction around the 'packet_read_with_status()' function. + */ +void packet_reader_init(struct packet_reader *reader, int fd, + char *src_buffer, size_t src_len, + int options); + +/* + * Perform a packet read and return the status of the read. + * The values of 'pktlen' and 'line' are updated based on the status of the + * read as follows: + * + * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL + * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read + * 'line' is set to point at the read line + * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL + */ +enum packet_read_status packet_reader_read(struct packet_reader *reader); + +/* + * Peek the next packet line without consuming it and return the status. + * The next call to 'packet_reader_read()' will perform a read of the same line + * that was peeked, consuming the line. + * + * Peeking multiple times without calling 'packet_reader_read()' will return + * the same result. + */ +enum packet_read_status packet_reader_peek(struct packet_reader *reader); + +#define DEFAULT_PACKET_MAX 1000 +#define LARGE_PACKET_MAX 65520 +#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4) +extern char packet_buffer[LARGE_PACKET_MAX]; + +struct packet_writer { + int dest_fd; + unsigned use_sideband : 1; +}; + +void packet_writer_init(struct packet_writer *writer, int dest_fd); + +/* These functions die upon failure. */ +__attribute__((format (printf, 2, 3))) +void packet_writer_write(struct packet_writer *writer, const char *fmt, ...); +__attribute__((format (printf, 2, 3))) +void packet_writer_error(struct packet_writer *writer, const char *fmt, ...); +void packet_writer_delim(struct packet_writer *writer); +void packet_writer_flush(struct packet_writer *writer); + +#endif -- cgit 1.4.1