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_errno("sha1 file '%s' write error", f->name);
  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_errno("%s: sha1 file error on close", f->name);
  59                fd = 0;
  60        } else
  61                fd = f->fd;
  62        free(f);
  63        return fd;
  64}
  65
  66int sha1write(struct sha1file *f, void *buf, unsigned int count)
  67{
  68        while (count) {
  69                unsigned offset = f->offset;
  70                unsigned left = sizeof(f->buffer) - offset;
  71                unsigned nr = count > left ? left : count;
  72                void *data;
  73
  74                if (f->do_crc)
  75                        f->crc32 = crc32(f->crc32, buf, nr);
  76
  77                if (nr == sizeof(f->buffer)) {
  78                        /* process full buffer directly without copy */
  79                        data = buf;
  80                } else {
  81                        memcpy(f->buffer + offset, buf, nr);
  82                        data = f->buffer;
  83                }
  84
  85                count -= nr;
  86                offset += nr;
  87                buf = (char *) buf + nr;
  88                left -= nr;
  89                if (!left) {
  90                        git_SHA1_Update(&f->ctx, data, offset);
  91                        flush(f, data, offset);
  92                        offset = 0;
  93                }
  94                f->offset = offset;
  95        }
  96        return 0;
  97}
  98
  99struct sha1file *sha1fd(int fd, const char *name)
 100{
 101        return sha1fd_throughput(fd, name, NULL);
 102}
 103
 104struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)
 105{
 106        struct sha1file *f = xmalloc(sizeof(*f));
 107        f->fd = fd;
 108        f->offset = 0;
 109        f->total = 0;
 110        f->tp = tp;
 111        f->name = name;
 112        f->do_crc = 0;
 113        git_SHA1_Init(&f->ctx);
 114        return f;
 115}
 116
 117void crc32_begin(struct sha1file *f)
 118{
 119        f->crc32 = crc32(0, Z_NULL, 0);
 120        f->do_crc = 1;
 121}
 122
 123uint32_t crc32_end(struct sha1file *f)
 124{
 125        f->do_crc = 0;
 126        return f->crc32;
 127}