Andrew's git - gitweb.git/blob

   1/*
   2 * csum-file.c
   3 *
   4 * Copyright (C) 2005 Linus Torvalds
   5 *
   6 * Simple file write infrastructure for writing SHA1-summed
   7 * files. Useful when you write a file that you want to be
   8 * able to verify hasn't been messed with afterwards.
   9 */
  10#include "cache.h"
  11#include "progress.h"
  12#include "csum-file.h"
  13
  14static void flush(struct sha1file *f, void * buf, unsigned int count)
  15{
  16        for (;;) {
  17                int ret = xwrite(f->fd, buf, count);
  18                if (ret > 0) {
  19                        f->total += ret;
  20                        display_throughput(f->tp, f->total);
  21                        buf = (char *) buf + ret;
  22                        count -= ret;
  23                        if (count)
  24                                continue;
  25                        return;
  26                }
  27                if (!ret)
  28                        die("sha1 file '%s' write error. Out of diskspace", f->name);
  29                die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
  30        }
  31}
  32
  33void sha1flush(struct sha1file *f)
  34{
  35        unsigned offset = f->offset;
  36
  37        if (offset) {
  38                git_SHA1_Update(&f->ctx, f->buffer, offset);
  39                flush(f, f->buffer, offset);
  40                f->offset = 0;
  41        }
  42}
  43
  44int sha1close(struct sha1file *f, unsigned char *result, unsigned int flags)
  45{
  46        int fd;
  47
  48        sha1flush(f);
  49        git_SHA1_Final(f->buffer, &f->ctx);
  50        if (result)
  51                hashcpy(result, f->buffer);
  52        if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
  53                /* write checksum and close fd */
  54                flush(f, f->buffer, 20);
  55                if (flags & CSUM_FSYNC)
  56                        fsync_or_die(f->fd, f->name);
  57                if (close(f->fd))
  58                        die("%s: sha1 file error on close (%s)",
  59                            f->name, strerror(errno));
  60                fd = 0;
  61        } else
  62                fd = f->fd;
  63        free(f);
  64        return fd;
  65}
  66
  67int sha1write(struct sha1file *f, void *buf, unsigned int count)
  68{
  69        while (count) {
  70                unsigned offset = f->offset;
  71                unsigned left = sizeof(f->buffer) - offset;
  72                unsigned nr = count > left ? left : count;
  73                void *data;
  74
  75                if (f->do_crc)
  76                        f->crc32 = crc32(f->crc32, buf, nr);
  77
  78                if (nr == sizeof(f->buffer)) {
  79                        /* process full buffer directly without copy */
  80                        data = buf;
  81                } else {
  82                        memcpy(f->buffer + offset, buf, nr);
  83                        data = f->buffer;
  84                }
  85
  86                count -= nr;
  87                offset += nr;
  88                buf = (char *) buf + nr;
  89                left -= nr;
  90                if (!left) {
  91                        git_SHA1_Update(&f->ctx, data, offset);
  92                        flush(f, data, offset);
  93                        offset = 0;
  94                }
  95                f->offset = offset;
  96        }
  97        return 0;
  98}
  99
 100struct sha1file *sha1fd(int fd, const char *name)
 101{
 102        return sha1fd_throughput(fd, name, NULL);
 103}
 104
 105struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
 106{
 107        struct sha1file *f = xmalloc(sizeof(*f));
 108        f->fd = fd;
 109        f->offset = 0;
 110        f->total = 0;
 111        f->tp = tp;
 112        f->name = name;
 113        f->do_crc = 0;
 114        git_SHA1_Init(&f->ctx);
 115        return f;
 116}
 117
 118void crc32_begin(struct sha1file *f)
 119{
 120        f->crc32 = crc32(0, Z_NULL, 0);
 121        f->do_crc = 1;
 122}
 123
 124uint32_t crc32_end(struct sha1file *f)
 125{
 126        f->do_crc = 0;
 127        return f->crc32;
 128}