sideband: reverse its dependency on pkt-line
[git/git.git] / pkt-line.h
CommitLineData
f3a3214e
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1#ifndef PKTLINE_H
2#define PKTLINE_H
3
07d68930 4#include "git-compat-util.h"
f5615d24 5#include "strbuf.h"
fbd76cd4 6#include "sideband.h"
07d68930 7
f3a3214e 8/*
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9 * Write a packetized stream, where each line is preceded by
10 * its length (including the header) as a 4-byte hex number.
11 * A length of 'zero' means end of stream (and a length of 1-3
12 * would be an error).
13 *
14 * This is all pretty stupid, but we use this packetized line
15 * format to make a streaming format possible without ever
16 * over-running the read buffers. That way we'll never read
17 * into what might be the pack data (which should go to another
18 * process entirely).
19 *
20 * The writing side could use stdio, but since the reading
21 * side can't, we stay with pure read/write interfaces.
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22 */
23void packet_flush(int fd);
a4cfd41c 24void packet_delim(int fd);
81c634e9 25void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
f5615d24 26void packet_buf_flush(struct strbuf *buf);
a4cfd41c 27void packet_buf_delim(struct strbuf *buf);
5d2124b3 28void packet_write(int fd_out, const char *buf, size_t size);
f5615d24 29void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
f1f4d8ac 30void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
038ce90f 31int packet_flush_gently(int fd);
70428d1a 32int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
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33int write_packetized_from_fd(int fd_in, int fd_out);
34int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);
f3a3214e 35
03809429 36/*
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37 * Read a packetized line into the buffer, which must be at least size bytes
38 * long. The return value specifies the number of bytes read into the buffer.
39 *
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40 * If src_buffer and *src_buffer are not NULL, it should point to a buffer
41 * containing the packet data to parse, of at least *src_len bytes. After the
42 * function returns, src_buf will be incremented and src_len decremented by the
43 * number of bytes consumed.
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44 *
45 * If src_buffer (or *src_buffer) is NULL, then data is read from the
46 * descriptor "fd".
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47 *
48 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
49 * of the following conditions:
50 *
51 * 1. Read error from descriptor.
52 *
53 * 2. Protocol error from the remote (e.g., bogus length characters).
54 *
55 * 3. Receiving a packet larger than "size" bytes.
56 *
57 * 4. Truncated output from the remote (e.g., we expected a packet but got
58 * EOF, or we got a partial packet followed by EOF).
59 *
60 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
61 * condition 4 (truncated input), but instead return -1. However, we will still
62 * die for the other 3 conditions.
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63 *
64 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
65 * present) is removed from the buffer before returning.
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66 *
67 * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an
68 * ERR packet.
03809429 69 */
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70#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
71#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
72#define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2)
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73int packet_read(int fd, char **src_buffer, size_t *src_len, char
74 *buffer, unsigned size, int options);
03809429 75
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76/*
77 * Read a packetized line into a buffer like the 'packet_read()' function but
78 * returns an 'enum packet_read_status' which indicates the status of the read.
79 * The number of bytes read will be assigined to *pktlen if the status of the
80 * read was 'PACKET_READ_NORMAL'.
81 */
82enum packet_read_status {
83 PACKET_READ_EOF,
84 PACKET_READ_NORMAL,
85 PACKET_READ_FLUSH,
a4cfd41c 86 PACKET_READ_DELIM,
2153d478
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87};
88enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
89 size_t *src_len, char *buffer,
90 unsigned size, int *pktlen,
91 int options);
92
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93/*
94 * Convenience wrapper for packet_read that is not gentle, and sets the
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95 * CHOMP_NEWLINE option. The return value is NULL for a flush packet,
96 * and otherwise points to a static buffer (that may be overwritten by
97 * subsequent calls). If the size parameter is not NULL, the length of the
98 * packet is written to it.
819b929d 99 */
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100char *packet_read_line(int fd, int *size);
101
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102/*
103 * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF
104 * and CHOMP_NEWLINE options. The return value specifies the number of bytes
105 * read into the buffer or -1 on truncated input. If the *dst_line parameter
106 * is not NULL it will return NULL for a flush packet or when the number of
107 * bytes copied is zero and otherwise points to a static buffer (that may be
108 * overwritten by subsequent calls). If the size parameter is not NULL, the
109 * length of the packet is written to it.
110 */
111int packet_read_line_gently(int fd, int *size, char **dst_line);
112
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113/*
114 * Same as packet_read_line, but read from a buf rather than a descriptor;
115 * see packet_read for details on how src_* is used.
116 */
117char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
03809429 118
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119/*
120 * Reads a stream of variable sized packets until a flush packet is detected.
121 */
122ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);
123
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124/*
125 * Receive multiplexed output stream over git native protocol.
126 * in_stream is the input stream from the remote, which carries data
127 * in pkt_line format with band designator. Demultiplex it into out
128 * and err and return error appropriately. Band #1 carries the
129 * primary payload. Things coming over band #2 is not necessarily
130 * error; they are usually informative message on the standard error
131 * stream, aka "verbose"). A message over band #3 is a signal that
132 * the remote died unexpectedly. A flush() concludes the stream.
133 *
134 * Returns SIDEBAND_FLUSH upon a normal conclusion, and SIDEBAND_PROTOCOL_ERROR
135 * or SIDEBAND_REMOTE_ERROR if an error occurred.
136 */
137int recv_sideband(const char *me, int in_stream, int out);
138
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139struct packet_reader {
140 /* source file descriptor */
141 int fd;
142
143 /* source buffer and its size */
144 char *src_buffer;
145 size_t src_len;
146
147 /* buffer that pkt-lines are read into and its size */
148 char *buffer;
149 unsigned buffer_size;
150
151 /* options to be used during reads */
152 int options;
153
154 /* status of the last read */
155 enum packet_read_status status;
156
157 /* length of data read during the last read */
158 int pktlen;
159
160 /* the last line read */
161 const char *line;
162
163 /* indicates if a line has been peeked */
164 int line_peeked;
165};
166
167/*
168 * Initialize a 'struct packet_reader' object which is an
169 * abstraction around the 'packet_read_with_status()' function.
170 */
171extern void packet_reader_init(struct packet_reader *reader, int fd,
172 char *src_buffer, size_t src_len,
173 int options);
174
175/*
176 * Perform a packet read and return the status of the read.
177 * The values of 'pktlen' and 'line' are updated based on the status of the
178 * read as follows:
179 *
180 * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL
181 * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read
182 * 'line' is set to point at the read line
183 * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL
184 */
185extern enum packet_read_status packet_reader_read(struct packet_reader *reader);
186
187/*
188 * Peek the next packet line without consuming it and return the status.
189 * The next call to 'packet_reader_read()' will perform a read of the same line
190 * that was peeked, consuming the line.
191 *
192 * Peeking multiple times without calling 'packet_reader_read()' will return
193 * the same result.
194 */
195extern enum packet_read_status packet_reader_peek(struct packet_reader *reader);
196
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197#define DEFAULT_PACKET_MAX 1000
198#define LARGE_PACKET_MAX 65520
bb643d8b 199#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
74543a04 200extern char packet_buffer[LARGE_PACKET_MAX];
047ec602 201
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202struct packet_writer {
203 int dest_fd;
204};
205
206void packet_writer_init(struct packet_writer *writer, int dest_fd);
207
208/* These functions die upon failure. */
209__attribute__((format (printf, 2, 3)))
210void packet_writer_write(struct packet_writer *writer, const char *fmt, ...);
211__attribute__((format (printf, 2, 3)))
212void packet_writer_error(struct packet_writer *writer, const char *fmt, ...);
213void packet_writer_delim(struct packet_writer *writer);
214void packet_writer_flush(struct packet_writer *writer);
215
f3a3214e 216#endif