Commit 740bba1c3179a597c83f7dd3a23bffb50a494bdf
2021-06-18T14:07:35
allow the delta base file to lose its header between deltify_init and deltify This simplifies pack file creation. A delta base could be read from a loose object, a packfile, or it might be available in a temporary file. All these cases can now be handled the same way. We may need to open, close, and re-open a given delta base multiple times while packing.
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diff --git a/lib/deltify.c b/lib/deltify.c
index bbacc26..b743863 100644
--- a/lib/deltify.c
+++ b/lib/deltify.c
@@ -96,7 +96,8 @@ hashblk(const unsigned char *p, off_t n)
}
static const struct got_error *
-addblk(struct got_delta_table *dt, FILE *f, off_t len, off_t offset, uint64_t h)
+addblk(struct got_delta_table *dt, FILE *f, off_t file_offset0, off_t len,
+ off_t offset, uint64_t h)
{
const struct got_error *err = NULL;
int i;
@@ -116,7 +117,7 @@ addblk(struct got_delta_table *dt, FILE *f, off_t len, off_t offset, uint64_t h)
*/
if (len == dt->blocks[i].len && h == dt->blocks[i].hash) {
if (r == 0) {
- if (fseeko(f, offset, SEEK_SET) == -1)
+ if (fseeko(f, file_offset0 + offset, SEEK_SET) == -1)
return got_error_from_errno("fseeko");
r = fread(buf, 1, len, f);
if (r != len) {
@@ -125,7 +126,8 @@ addblk(struct got_delta_table *dt, FILE *f, off_t len, off_t offset, uint64_t h)
return got_ferror(f, GOT_ERR_IO);
}
}
- if (fseeko(f, dt->blocks[i].offset, SEEK_SET) == -1)
+ if (fseeko(f, file_offset0 + dt->blocks[i].offset,
+ SEEK_SET) == -1)
return got_error_from_errno("fseeko");
if (fread(buf2, 1, len, f) != len)
return got_ferror(f, GOT_ERR_IO);
@@ -160,8 +162,8 @@ addblk(struct got_delta_table *dt, FILE *f, off_t len, off_t offset, uint64_t h)
for (i = 0; i < old_size; i++) {
if (db[i].len == 0)
continue;
- err = addblk(dt, f, db[i].len, db[i].offset,
- db[i].hash);
+ err = addblk(dt, f, file_offset0, db[i].len,
+ db[i].offset, db[i].hash);
if (err)
break;
}
@@ -173,7 +175,7 @@ addblk(struct got_delta_table *dt, FILE *f, off_t len, off_t offset, uint64_t h)
static const struct got_error *
lookupblk(struct got_delta_block **block, struct got_delta_table *dt,
- unsigned char *p, off_t len, FILE *basefile)
+ unsigned char *p, off_t len, FILE *basefile, off_t basefile_offset0)
{
int i;
uint64_t h;
@@ -188,7 +190,8 @@ lookupblk(struct got_delta_block **block, struct got_delta_table *dt,
if (dt->blocks[i].hash != h ||
dt->blocks[i].len != len)
continue;
- if (fseeko(basefile, dt->blocks[i].offset, SEEK_SET) == -1)
+ if (fseeko(basefile, basefile_offset0 + dt->blocks[i].offset,
+ SEEK_SET) == -1)
return got_error_from_errno("fseeko");
r = fread(buf, 1, len, basefile);
if (r != len)
@@ -239,6 +242,7 @@ got_deltify_init(struct got_delta_table **dt, FILE *f, off_t fileoffset,
{
const struct got_error *err = NULL;
uint64_t h;
+ const off_t offset0 = fileoffset;
*dt = calloc(1, sizeof(**dt));
if (*dt == NULL)
@@ -264,7 +268,8 @@ got_deltify_init(struct got_delta_table **dt, FILE *f, off_t fileoffset,
if (blocklen == 0)
break;
h = hashblk(buf, blocklen);
- err = addblk(*dt, f, blocklen, fileoffset, h);
+ err = addblk(*dt, f, offset0, blocklen,
+ fileoffset - offset0, h);
if (err)
goto done;
fileoffset += blocklen;
@@ -310,14 +315,14 @@ emitdelta(struct got_delta_instruction **deltas, int *ndeltas, int copy,
}
static const struct got_error *
-stretchblk(FILE *basefile, struct got_delta_block *block, FILE *f,
- off_t filesize, off_t *blocklen)
+stretchblk(FILE *basefile, off_t base_offset0, struct got_delta_block *block,
+ FILE *f, off_t filesize, off_t *blocklen)
{
uint8_t basebuf[GOT_DELTIFY_MAXCHUNK], buf[GOT_DELTIFY_MAXCHUNK];
size_t base_r, r, i;
int buf_equal = 1;
- if (fseeko(basefile, block->offset, SEEK_SET) == -1)
+ if (fseeko(basefile, base_offset0 + block->offset, SEEK_SET) == -1)
return got_error_from_errno("fseeko");
while (buf_equal && *blocklen < (1 << 24) - 1) {
@@ -374,7 +379,8 @@ got_deltify(struct got_delta_instruction **deltas, int *ndeltas,
break;
if (blocklen == 0)
break;
- err = lookupblk(&block, dt, buf, blocklen, basefile);
+ err = lookupblk(&block, dt, buf, blocklen, basefile,
+ basefile_offset0);
if (err)
break;
if (block != NULL) {
@@ -383,8 +389,8 @@ got_deltify(struct got_delta_instruction **deltas, int *ndeltas,
* Attempt to stretch the block as far as possible and
* generate a copy instruction.
*/
- err = stretchblk(basefile, block, f, filesize,
- &blocklen);
+ err = stretchblk(basefile, basefile_offset0, block,
+ f, filesize, &blocklen);
if (err)
break;
err = emitdelta(deltas, ndeltas, 1, block->offset, blocklen);