/**
* Iterate on each item of the map, applying callback.
*/
void
map_foreach(const map_t *m, keyval_fn_t cb, void *u)
{
map_check(m);
g_assert(cb);
switch (m->type) {
case MAP_HASH:
htable_foreach(m->u.ht, (ckeyval_fn_t) cb, u);
break;
case MAP_ORDERED_HASH:
ohash_table_foreach(m->u.ot, cb, u);
break;
case MAP_PATRICIA:
{
struct pat_foreach ctx;
ctx.cb = cb;
ctx.u = u;
patricia_foreach(m->u.pt, pat_foreach_wrapper, &ctx);
}
break;
case MAP_MAXTYPE:
g_assert_not_reached();
}
}
/**
* ccache_free(cache):
* Free the cache and all of its entries.
*/
void
ccache_free(CCACHE * cache)
{
struct ccache_internal * C = cache;
if (cache == NULL)
return;
/* Free all of the records in the patricia tree. */
patricia_foreach(C->tree, callback_free, NULL);
/* Free the patricia tree itself. */
patricia_free(C->tree);
/* Unmap memory. */
#ifdef HAVE_MMAP
if (C->datalen > 0 && munmap(C->data, C->datalen))
warnp("munmap failed on cache data");
#else
free(C->data);
#endif
/* Free the cache. */
free(C);
}
/**
* ccache_read(path):
* Read the chunkification cache (if present) from the directory ${path};
* return a Patricia tree mapping absolute paths to cache entries.
*/
CCACHE *
ccache_read(const char * path)
{
struct ccache_internal * C;
struct ccache_read_internal R;
struct ccache_record * ccr;
#ifdef HAVE_MMAP
struct stat sb;
off_t fpos;
long int pagesize;
#endif
size_t i;
uint8_t N[4];
/* The caller must pass a file name to be read. */
assert(path != NULL);
/* Allocate memory for the cache. */
if ((C = malloc(sizeof(struct ccache_internal))) == NULL)
goto err0;
memset(C, 0, sizeof(struct ccache_internal));
/* Create a Patricia tree to store cache entries. */
if ((C->tree = patricia_init()) == NULL)
goto err1;
/* Construct the name of cache file. */
if (asprintf(&R.s, "%s/cache", path) == -1) {
warnp("asprintf");
goto err2;
}
/* Open the cache file. */
if ((R.f = fopen(R.s, "r")) == NULL) {
/* ENOENT isn't an error. */
if (errno != ENOENT) {
warnp("fopen(%s)", R.s);
goto err3;
}
/* No cache exists on disk; return an empty cache. */
goto emptycache;
}
/**
* We read the cache file in three steps:
* 1. Read a little-endian uint32_t which indicates the number of
* records in the cache file.
* 2. Read N (record, path suffix) pairs and insert them into a
* Patricia tree.
* 3. Iterate through the tree and read chunk headers and compressed
* entry trailers.
*/
/* Read the number of cache entries. */
if (fread(N, 4, 1, R.f) != 1) {
if (ferror(R.f))
warnp("Error reading cache: %s", R.s);
else
warn0("Error reading cache: %s", R.s);
goto err4;
}
R.N = le32dec(N);
/* Read N (record, path suffix) pairs. */
R.sbuf = NULL;
R.sbuflen = R.slen = R.datalen = 0;
for (i = 0; i < R.N; i++) {
if ((ccr = read_rec(&R)) == NULL)
goto err5;
if (patricia_insert(C->tree, R.sbuf, R.slen, ccr))
goto err5;
C->chunksusage += ccr->nch * sizeof(struct chunkheader);
C->trailerusage += ccr->tzlen;
}
#ifdef HAVE_MMAP
/* Obtain page size, since mmapped regions must be page-aligned. */
if ((pagesize = sysconf(_SC_PAGESIZE)) == -1) {
warnp("sysconf(_SC_PAGESIZE)");
goto err5;
}
/* Map the remainder of the cache into memory. */
fpos = ftello(R.f);
if (fpos == -1) {
warnp("ftello(%s)", R.s);
goto err5;
}
if (fstat(fileno(R.f), &sb)) {
warnp("fstat(%s)", R.s);
goto err5;
}
if (sb.st_size != (off_t)(fpos + R.datalen)) {
warn0("Cache has incorrect size (%jd, expected %jd)\n",
(intmax_t)(sb.st_size), (intmax_t)(fpos + R.datalen));
goto err5;
}
C->datalen = R.datalen + (fpos % pagesize);
if ((C->data = mmap(NULL, C->datalen, PROT_READ,
#ifdef MAP_NOCORE
MAP_PRIVATE | MAP_NOCORE,
#else
MAP_PRIVATE,
#endif
fileno(R.f), fpos - (fpos % pagesize))) == MAP_FAILED) {
warnp("mmap(%s)", R.s);
goto err5;
}
R.data = (uint8_t *)C->data + (fpos % pagesize);
#else
/* Allocate space. */
C->datalen = R.datalen;
if (((C->data = malloc(C->datalen)) == NULL) && (C->datalen > 0))
goto err5;
if (fread(C->data, C->datalen, 1, R.f) != 1) {
warnp("fread(%s)", R.s);
goto err6;
}
R.data = (uint8_t *)C->data;
#endif
/* Iterate through the tree reading chunk headers and trailers. */
if (patricia_foreach(C->tree, callback_read_data, &R)) {
warnp("Error reading cache: %s", R.s);
goto err6;
}
/* Free buffer used for storing paths. */
free(R.sbuf);
/* Close the cache file. */
fclose(R.f);
/* Free string allocated by asprintf. */
free(R.s);
/* Success! */
return (C);
emptycache:
/* Nothing went wrong, but there's nothing on disk. */
free(R.s);
return (C);
err6:
#ifdef HAVE_MMAP
if (C->datalen > 0)
munmap(C->data, C->datalen);
#else
free(C->data);
#endif
err5:
free(R.sbuf);
patricia_foreach(C->tree, callback_free, NULL);
err4:
fclose(R.f);
err3:
free(R.s);
err2:
patricia_free(C->tree);
err1:
free(C);
err0:
/* Failure! */
return (NULL);
}
/**
* ccache_write(cache, path):
* Write the given chunkification cache into the directory ${path}.
*/
int
ccache_write(CCACHE * cache, const char * path)
{
struct ccache_internal * C = cache;
struct ccache_write_internal W;
uint8_t N[4];
char * s_old;
/* Construct name of temporary cache file. */
if (asprintf(&W.s, "%s/cache.new", path) == -1) {
warnp("asprintf");
goto err0;
}
/* Open the cache file for writing. */
if ((W.f = fopen(W.s, "w")) == NULL) {
warnp("fopen(%s)", W.s);
goto err1;
}
/**
* We make three passes through the cache tree:
* 1. Counting the number of records which will be written to disk.
* This is necessary since records in the cache which are too old
* will not be written, but the on-disk cache format starts with
* the number of records.
* 2. Writing the records and suffixes.
* 3. Writing the cached chunk headers and compressed entry trailers.
*/
/* Count the number of records which need to be written. */
W.N = 0;
if (patricia_foreach(C->tree, callback_count, &W)) {
warnp("patricia_foreach");
goto err2;
};
/* Write the number of records to the file. */
le32enc(N, W.N);
if (fwrite(N, 4, 1, W.f) != 1) {
warnp("fwrite(%s)", W.s);
goto err2;
}
/* Write the records and suffixes. */
W.sbuf = NULL;
W.sbuflen = 0;
if (patricia_foreach(C->tree, callback_write_rec, &W)) {
warnp("Error writing cache to %s", W.s);
goto err2;
}
free(W.sbuf);
/* Write the chunk headers and compressed entry trailers. */
if (patricia_foreach(C->tree, callback_write_data, &W)) {
warnp("Error writing cache to %s", W.s);
goto err2;
}
/* Close the file. */
fclose(W.f);
/* Construct the name of the old cache file. */
if (asprintf(&s_old, "%s/cache", path) == -1) {
warnp("asprintf");
goto err1;
}
/* Delete the old file, if it exists. */
if (unlink(s_old)) {
if (errno != ENOENT) {
warnp("unlink(%s)", s_old);
free(s_old);
goto err1;
}
}
/* Move the new cache file into place. */
if (rename(W.s, s_old)) {
warnp("rename(%s, %s)", W.s, s_old);
free(s_old);
goto err1;
}
/* Free strings allocated by asprintf. */
free(s_old);
free(W.s);
/* Success! */
return (0);
err2:
fclose(W.f);
err1:
free(W.s);
err0:
/* Failure! */
return (-1);
}
