#include "cache.h"
#include "pkt-line.h"
#include "run-command.h"

char packet_buffer[LARGE_PACKET_MAX];
static const char *packet_trace_prefix = "git";
static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);

void packet_trace_identity(const char *prog)
{
        packet_trace_prefix = xstrdup(prog);
}

static const char *get_trace_prefix(void)
{
        return in_async() ? "sideband" : packet_trace_prefix;
}

static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
{
        if (!sideband) {
                trace_verbatim(&trace_pack, buf, len);
                return 1;
        } else if (len && *buf == '\1') {
                trace_verbatim(&trace_pack, buf + 1, len - 1);
                return 1;
        } else {
                /* it's another non-pack sideband */
                return 0;
        }
}

static void packet_trace(const char *buf, unsigned int len, int write)
{
        int i;
        struct strbuf out;
        static int in_pack, sideband;

        if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
                return;

        if (in_pack) {
                if (packet_trace_pack(buf, len, sideband))
                        return;
        } else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
                in_pack = 1;
                sideband = *buf == '\1';
                packet_trace_pack(buf, len, sideband);

                /*
                 * Make a note in the human-readable trace that the pack data
                 * started.
                 */
                buf = "PACK ...";
                len = strlen(buf);
        }

        if (!trace_want(&trace_packet))
                return;

        /* +32 is just a guess for header + quoting */
        strbuf_init(&out, len+32);

        strbuf_addf(&out, "packet: %12s%c ",
                    get_trace_prefix(), write ? '>' : '<');

        /* XXX we should really handle printable utf8 */
        for (i = 0; i < len; i++) {
                /* suppress newlines */
                if (buf[i] == '\n')
                        continue;
                if (buf[i] >= 0x20 && buf[i] <= 0x7e)
                        strbuf_addch(&out, buf[i]);
                else
                        strbuf_addf(&out, "\\%o", buf[i]);
        }

        strbuf_addch(&out, '\n');
        trace_strbuf(&trace_packet, &out);
        strbuf_release(&out);
}

/*
 * If we buffered things up above (we don't, but we should),
 * we'd flush it here
 */
void packet_flush(int fd)
{
        packet_trace("0000", 4, 1);
        write_or_die(fd, "0000", 4);
}

void packet_delim(int fd)
{
        packet_trace("0001", 4, 1);
        write_or_die(fd, "0001", 4);
}

int packet_flush_gently(int fd)
{
        packet_trace("0000", 4, 1);
        if (write_in_full(fd, "0000", 4) < 0)
                return error("flush packet write failed");
        return 0;
}

void packet_buf_flush(struct strbuf *buf)
{
        packet_trace("0000", 4, 1);
        strbuf_add(buf, "0000", 4);
}

void packet_buf_delim(struct strbuf *buf)
{
        packet_trace("0001", 4, 1);
        strbuf_add(buf, "0001", 4);
}

static void set_packet_header(char *buf, const int size)
{
        static char hexchar[] = "0123456789abcdef";

        #define hex(a) (hexchar[(a) & 15])
        buf[0] = hex(size >> 12);
        buf[1] = hex(size >> 8);
        buf[2] = hex(size >> 4);
        buf[3] = hex(size);
        #undef hex
}

static void format_packet(struct strbuf *out, const char *fmt, va_list args)
{
        size_t orig_len, n;

        orig_len = out->len;
        strbuf_addstr(out, "0000");
        strbuf_vaddf(out, fmt, args);
        n = out->len - orig_len;

        if (n > LARGE_PACKET_MAX)
                die("protocol error: impossibly long line");

        set_packet_header(&out->buf[orig_len], n);
        packet_trace(out->buf + orig_len + 4, n - 4, 1);
}

static int packet_write_fmt_1(int fd, int gently,
                              const char *fmt, va_list args)
{
        static struct strbuf buf = STRBUF_INIT;

        strbuf_reset(&buf);
        format_packet(&buf, fmt, args);
        if (write_in_full(fd, buf.buf, buf.len) < 0) {
                if (!gently) {
                        check_pipe(errno);
                        die_errno("packet write with format failed");
                }
                return error("packet write with format failed");
        }

        return 0;
}

void packet_write_fmt(int fd, const char *fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        packet_write_fmt_1(fd, 0, fmt, args);
        va_end(args);
}

int packet_write_fmt_gently(int fd, const char *fmt, ...)
{
        int status;
        va_list args;

        va_start(args, fmt);
        status = packet_write_fmt_1(fd, 1, fmt, args);
        va_end(args);
        return status;
}

static int packet_write_gently(const int fd_out, const char *buf, size_t size)
{
        static char packet_write_buffer[LARGE_PACKET_MAX];
        size_t packet_size;

        if (size > sizeof(packet_write_buffer) - 4)
                return error("packet write failed - data exceeds max packet size");

        packet_trace(buf, size, 1);
        packet_size = size + 4;
        set_packet_header(packet_write_buffer, packet_size);
        memcpy(packet_write_buffer + 4, buf, size);
        if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
                return error("packet write failed");
        return 0;
}

void packet_write(int fd_out, const char *buf, size_t size)
{
        if (packet_write_gently(fd_out, buf, size))
                die_errno("packet write failed");
}

void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        format_packet(buf, fmt, args);
        va_end(args);
}

void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
{
        size_t orig_len, n;

        orig_len = buf->len;
        strbuf_addstr(buf, "0000");
        strbuf_add(buf, data, len);
        n = buf->len - orig_len;

        if (n > LARGE_PACKET_MAX)
                die("protocol error: impossibly long line");

        set_packet_header(&buf->buf[orig_len], n);
        packet_trace(data, len, 1);
}

int write_packetized_from_fd(int fd_in, int fd_out)
{
        static char buf[LARGE_PACKET_DATA_MAX];
        int err = 0;
        ssize_t bytes_to_write;

        while (!err) {
                bytes_to_write = xread(fd_in, buf, sizeof(buf));
                if (bytes_to_write < 0)
                        return COPY_READ_ERROR;
                if (bytes_to_write == 0)
                        break;
                err = packet_write_gently(fd_out, buf, bytes_to_write);
        }
        if (!err)
                err = packet_flush_gently(fd_out);
        return err;
}

int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
{
        int err = 0;
        size_t bytes_written = 0;
        size_t bytes_to_write;

        while (!err) {
                if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
                        bytes_to_write = LARGE_PACKET_DATA_MAX;
                else
                        bytes_to_write = len - bytes_written;
                if (bytes_to_write == 0)
                        break;
                err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
                bytes_written += bytes_to_write;
        }
        if (!err)
                err = packet_flush_gently(fd_out);
        return err;
}

static int get_packet_data(int fd, char **src_buf, size_t *src_size,
                           void *dst, unsigned size, int options)
{
        ssize_t ret;

        if (fd >= 0 && src_buf && *src_buf)
                die("BUG: multiple sources given to packet_read");

        /* Read up to "size" bytes from our source, whatever it is. */
        if (src_buf && *src_buf) {
                ret = size < *src_size ? size : *src_size;
                memcpy(dst, *src_buf, ret);
                *src_buf += ret;
                *src_size -= ret;
        } else {
                ret = read_in_full(fd, dst, size);
                if (ret < 0)
                        die_errno("read error");
        }

        /* And complain if we didn't get enough bytes to satisfy the read. */
        if (ret != size) {
                if (options & PACKET_READ_GENTLE_ON_EOF)
                        return -1;

                die("The remote end hung up unexpectedly");
        }

        return ret;
}

static int packet_length(const char *linelen)
{
        int val = hex2chr(linelen);
        return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
}

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)
{
        int len;
        char linelen[4];

        if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
                *pktlen = -1;
                return PACKET_READ_EOF;
        }

        len = packet_length(linelen);

        if (len < 0) {
                die("protocol error: bad line length character: %.4s", linelen);
        } else if (!len) {
                packet_trace("0000", 4, 0);
                *pktlen = 0;
                return PACKET_READ_FLUSH;
        } else if (len == 1) {
                packet_trace("0001", 4, 0);
                *pktlen = 0;
                return PACKET_READ_DELIM;
        } else if (len < 4) {
                die("protocol error: bad line length %d", len);
        }

        len -= 4;
        if ((unsigned)len >= size)
                die("protocol error: bad line length %d", len);

        if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
                *pktlen = -1;
                return PACKET_READ_EOF;
        }

        if ((options & PACKET_READ_CHOMP_NEWLINE) &&
            len && buffer[len-1] == '\n')
                len--;

        buffer[len] = 0;
        packet_trace(buffer, len, 0);
        *pktlen = len;
        return PACKET_READ_NORMAL;
}

int packet_read(int fd, char **src_buffer, size_t *src_len,
                char *buffer, unsigned size, int options)
{
        int pktlen = -1;

        packet_read_with_status(fd, src_buffer, src_len, buffer, size,
                                &pktlen, options);

        return pktlen;
}

static char *packet_read_line_generic(int fd,
                                      char **src, size_t *src_len,
                                      int *dst_len)
{
        int len = packet_read(fd, src, src_len,
                              packet_buffer, sizeof(packet_buffer),
                              PACKET_READ_CHOMP_NEWLINE);
        if (dst_len)
                *dst_len = len;
        return (len > 0) ? packet_buffer : NULL;
}

char *packet_read_line(int fd, int *len_p)
{
        return packet_read_line_generic(fd, NULL, NULL, len_p);
}

int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
{
        int len = packet_read(fd, NULL, NULL,
                              packet_buffer, sizeof(packet_buffer),
                              PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
        if (dst_len)
                *dst_len = len;
        if (dst_line)
                *dst_line = (len > 0) ? packet_buffer : NULL;
        return len;
}

char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
{
        return packet_read_line_generic(-1, src, src_len, dst_len);
}

ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
{
        int packet_len;

        size_t orig_len = sb_out->len;
        size_t orig_alloc = sb_out->alloc;

        for (;;) {
                strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
                packet_len = packet_read(fd_in, NULL, NULL,
                        /* strbuf_grow() above always allocates one extra byte to
                         * store a '\0' at the end of the string. packet_read()
                         * writes a '\0' extra byte at the end, too. Let it know
                         * that there is already room for the extra byte.
                         */
                        sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
                        PACKET_READ_GENTLE_ON_EOF);
                if (packet_len <= 0)
                        break;
                sb_out->len += packet_len;
        }

        if (packet_len < 0) {
                if (orig_alloc == 0)
                        strbuf_release(sb_out);
                else
                        strbuf_setlen(sb_out, orig_len);
                return packet_len;
        }
        return sb_out->len - orig_len;
}

/* Packet Reader Functions */
void packet_reader_init(struct packet_reader *reader, int fd,
                        char *src_buffer, size_t src_len,
                        int options)
{
        memset(reader, 0, sizeof(*reader));

        reader->fd = fd;
        reader->src_buffer = src_buffer;
        reader->src_len = src_len;
        reader->buffer = packet_buffer;
        reader->buffer_size = sizeof(packet_buffer);
        reader->options = options;
}

enum packet_read_status packet_reader_read(struct packet_reader *reader)
{
        if (reader->line_peeked) {
                reader->line_peeked = 0;
                return reader->status;
        }

        reader->status = packet_read_with_status(reader->fd,
                                                 &reader->src_buffer,
                                                 &reader->src_len,
                                                 reader->buffer,
                                                 reader->buffer_size,
                                                 &reader->pktlen,
                                                 reader->options);

        if (reader->status == PACKET_READ_NORMAL)
                reader->line = reader->buffer;
        else
                reader->line = NULL;

        return reader->status;
}

enum packet_read_status packet_reader_peek(struct packet_reader *reader)
{
        /* Only allow peeking a single line */
        if (reader->line_peeked)
                return reader->status;

        /* Peek a line by reading it and setting peeked flag */
        packet_reader_read(reader);
        reader->line_peeked = 1;
        return reader->status;
}