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/*

* csum-file.c

*

* Copyright (C) 2005 Linus Torvalds

*

* Simple file write infrastructure for writing SHA1-summed

* files. Useful when you write a file that you want to be

* able to verify hasn't been messed with afterwards.

*/

#include "cache.h"

#include "progress.h"

#include "csum-file.h"

static void flush(struct sha1file *f, const void *buf, unsigned int count)

{

if (0 <= f->check_fd && count) {

unsigned char check_buffer[8192];

ssize_t ret = read_in_full(f->check_fd, check_buffer, count);

if (ret < 0)

die_errno("%s: sha1 file read error", f->name);

if (ret < count)

die("%s: sha1 file truncated", f->name);

if (memcmp(buf, check_buffer, count))

die("sha1 file '%s' validation error", f->name);

}

for (;;) {

int ret = xwrite(f->fd, buf, count);

if (ret > 0) {

f->total += ret;

display_throughput(f->tp, f->total);

buf = (char *) buf + ret;

count -= ret;

if (count)

continue;

return;

}

if (!ret)

die("sha1 file '%s' write error. Out of diskspace", f->name);

die_errno("sha1 file '%s' write error", f->name);

}

}

void sha1flush(struct sha1file *f)

{

unsigned offset = f->offset;

if (offset) {

git_SHA1_Update(&f->ctx, f->buffer, offset);

flush(f, f->buffer, offset);

f->offset = 0;

}

}

int sha1close(struct sha1file *f, unsigned char *result, unsigned int flags)

{

int fd;

sha1flush(f);

git_SHA1_Final(f->buffer, &f->ctx);

if (result)

hashcpy(result, f->buffer);

if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {

/* write checksum and close fd */

flush(f, f->buffer, 20);

if (flags & CSUM_FSYNC)

fsync_or_die(f->fd, f->name);

if (close(f->fd))

die_errno("%s: sha1 file error on close", f->name);

fd = 0;

} else

fd = f->fd;

if (0 <= f->check_fd) {

char discard;

int cnt = read_in_full(f->check_fd, &discard, 1);

if (cnt < 0)

die_errno("%s: error when reading the tail of sha1 file",

f->name);

if (cnt)

die("%s: sha1 file has trailing garbage", f->name);

if (close(f->check_fd))

die_errno("%s: sha1 file error on close", f->name);

}

free(f);

return fd;

}

void sha1write(struct sha1file *f, const void *buf, unsigned int count)

{

while (count) {

unsigned offset = f->offset;

unsigned left = sizeof(f->buffer) - offset;

unsigned nr = count > left ? left : count;

const void *data;

if (f->do_crc)

f->crc32 = crc32(f->crc32, buf, nr);

if (nr == sizeof(f->buffer)) {

/* process full buffer directly without copy */

data = buf;

} else {

memcpy(f->buffer + offset, buf, nr);

data = f->buffer;

}

count -= nr;

offset += nr;

buf = (char *) buf + nr;

left -= nr;

if (!left) {

git_SHA1_Update(&f->ctx, data, offset);

flush(f, data, offset);

offset = 0;

}

f->offset = offset;

}

}

struct sha1file *sha1fd(int fd, const char *name)

{

return sha1fd_throughput(fd, name, NULL);

}

struct sha1file *sha1fd_check(const char *name)

{

int sink, check;

struct sha1file *f;

sink = open("/dev/null", O_WRONLY);

if (sink < 0)

die_errno("unable to open /dev/null");

check = open(name, O_RDONLY);

if (check < 0)

die_errno("unable to open '%s'", name);

f = sha1fd(sink, name);

f->check_fd = check;

return f;

}

struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp)

{

struct sha1file *f = xmalloc(sizeof(*f));

f->fd = fd;

f->check_fd = -1;

f->offset = 0;

f->total = 0;

f->tp = tp;

f->name = name;

f->do_crc = 0;

git_SHA1_Init(&f->ctx);

return f;

}

void sha1file_checkpoint(struct sha1file *f, struct sha1file_checkpoint *checkpoint)

{

sha1flush(f);

checkpoint->offset = f->total;

checkpoint->ctx = f->ctx;

}

int sha1file_truncate(struct sha1file *f, struct sha1file_checkpoint *checkpoint)

{

off_t offset = checkpoint->offset;

if (ftruncate(f->fd, offset) ||

lseek(f->fd, offset, SEEK_SET) != offset)

return -1;

f->total = offset;

f->ctx = checkpoint->ctx;

f->offset = 0; /* sha1flush() was called in checkpoint */

return 0;

}

void crc32_begin(struct sha1file *f)

{

f->crc32 = crc32(0, NULL, 0);

f->do_crc = 1;

}

uint32_t crc32_end(struct sha1file *f)

{

f->do_crc = 0;

return f->crc32;

}