1 files changed, 251 insertions, 0 deletions
diff --git a/pkt-line.h b/pkt-line.h
new file mode 100644
index 0000000..954eec8
--- /dev/null
+++ b/pkt-line.h
@@ -0,0 +1,251 @@
+#ifndef PKTLINE_H
+#define PKTLINE_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_response_end(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)));
+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_no_flush(int fd_in, int fd_out);
+int write_packetized_from_buf_no_flush_count(const char *src_in, size_t len,
+					     int fd_out, int *packet_counter);
+static inline int write_packetized_from_buf_no_flush(const char *src_in,
+						     size_t len, int fd_out)
+{
+	return write_packetized_from_buf_no_flush_count(src_in, len, fd_out, NULL);
+}
+
+/*
+ * Stdio versions of packet_write functions. When mixing these with fd
+ * based functions, take care to call fflush(3) before doing fd writes or
+ * closing the fd.
+ */
+void packet_fwrite(FILE *f, const char *buf, size_t size);
+void packet_fwrite_fmt(FILE *f, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
+
+/* packet_fflush writes a flush packet and flushes the stdio buffer of f */
+void packet_fflush(FILE *f);
+
+/*
+ * 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 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.
+ *
+ * If options contains PACKET_READ_GENTLE_ON_READ_ERROR, we will not die
+ * on read errors, but instead return -1.  However, we may still die on an
+ * ERR packet (if requested).
+ */
+#define PACKET_READ_GENTLE_ON_EOF        (1u<<0)
+#define PACKET_READ_CHOMP_NEWLINE        (1u<<1)
+#define PACKET_READ_DIE_ON_ERR_PACKET    (1u<<2)
+#define PACKET_READ_GENTLE_ON_READ_ERROR (1u<<3)
+#define PACKET_READ_REDACT_URI_PATH      (1u<<4)
+int packet_read(int fd, char *buffer, unsigned size, int options);
+
+/*
+ * Convert a four hex digit packet line length header into its numeric
+ * representation.
+ *
+ * If lenbuf_hex contains non-hex characters, return -1. Otherwise, return the
+ * numeric value of the length header.
+ */
+int packet_length(const char lenbuf_hex[4], size_t size);
+
+/*
+ * 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 assigned to *pktlen if the status of the
+ * read was 'PACKET_READ_NORMAL'.
+ *
+ * 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".
+ */
+enum packet_read_status {
+	PACKET_READ_EOF,
+	PACKET_READ_NORMAL,
+	PACKET_READ_FLUSH,
+	PACKET_READ_DELIM,
+	PACKET_READ_RESPONSE_END,
+};
+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);
+
+/*
+ * 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, int options);
+
+/*
+ * 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;
+
+	/* hash algorithm in use */
+	const struct git_hash_algo *hash_algo;
+};
+
+/*
+ * 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);
+
+void packet_trace_identity(const char *prog);
+
+#endif