We've made huge changes to this file, and some of the old names and
comments are no longer very fitting. So rename a bunch of things:
* `struct packed_ref_cache` → `struct snapshot`
* `acquire_packed_ref_cache()` → `acquire_snapshot()`
* `release_packed_ref_buffer()` → `clear_snapshot_buffer()`
* `release_packed_ref_cache()` → `release_snapshot()`
* `clear_packed_ref_cache()` → `clear_snapshot()`
* `struct packed_ref_entry` → `struct snapshot_record`
* `cmp_packed_ref_entries()` → `cmp_packed_ref_records()`
* `cmp_entry_to_refname()` → `cmp_record_to_refname()`
* `sort_packed_refs()` → `sort_snapshot()`
* `read_packed_refs()` → `create_snapshot()`
* `validate_packed_ref_cache()` → `validate_snapshot()`
* `get_packed_ref_cache()` → `get_snapshot()`
* Renamed local variables and struct members accordingly.
Also update a bunch of comments to reflect the renaming and the
accumulated changes that the code has undergone.
Signed-off-by: Michael Haggerty <mhag...@alum.mit.edu>
---
refs/packed-backend.c | 422 +++++++++++++++++++++++++++-----------------------
1 file changed, 232 insertions(+), 190 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 1ed52d7eca..d500ebfaa5 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -37,10 +37,30 @@ static enum mmap_strategy mmap_strategy = MMAP_OK;
struct packed_ref_store;
-struct packed_ref_cache {
+/*
+ * A `snapshot` represents one snapshot of a `packed-refs` file.
+ *
+ * Normally, this will be a mmapped view of the contents of the
+ * `packed-refs` file at the time the snapshot was created. However,
+ * if the `packed-refs` file was not sorted, this might point at heap
+ * memory holding the contents of the `packed-refs` file with its
+ * records sorted by refname.
+ *
+ * `snapshot` instances are reference counted (via
+ * `acquire_snapshot()` and `release_snapshot()`). This is to prevent
+ * an instance from disappearing while an iterator is still iterating
+ * over it. Instances are garbage collected when their `referrers`
+ * count goes to zero.
+ *
+ * The most recent `snapshot`, if available, is referenced by the
+ * `packed_ref_store`. Its freshness is checked whenever
+ * `get_snapshot()` is called; if the existing snapshot is obsolete, a
+ * new snapshot is taken.
+ */
+struct snapshot {
/*
* A back-pointer to the packed_ref_store with which this
- * cache is associated:
+ * snapshot is associated:
*/
struct packed_ref_store *refs;
@@ -61,26 +81,42 @@ struct packed_ref_cache {
size_t header_len;
/*
- * What is the peeled state of this cache? (This is usually
- * determined from the header of the "packed-refs" file.)
+ * What is the peeled state of the `packed-refs` file that
+ * this snapshot represents? (This is usually determined from
+ * the file's header.)
*/
enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled;
/*
- * Count of references to the data structure in this instance,
- * including the pointer from files_ref_store::packed if any.
- * The data will not be freed as long as the reference count
- * is nonzero.
+ * Count of references to this instance, including the pointer
+ * from `packed_ref_store::snapshot`, if any. The instance
+ * will not be freed as long as the reference count is
+ * nonzero.
*/
unsigned int referrers;
- /* The metadata from when this packed-refs cache was read */
+ /*
+ * The metadata of the `packed-refs` file from which this
+ * snapshot was created, used to tell if the file has been
+ * replaced since we read it.
+ */
struct stat_validity validity;
};
/*
- * A container for `packed-refs`-related data. It is not (yet) a
- * `ref_store`.
+ * A `ref_store` representing references stored in a `packed-refs`
+ * file. It implements the `ref_store` interface, though it has some
+ * limitations:
+ *
+ * - It cannot store symbolic references.
+ *
+ * - It cannot store reflogs.
+ *
+ * - It does not support reference renaming (though it could).
+ *
+ * On the other hand, it can be locked outside of a reference
+ * transaction. In that case, it remains locked even after the
+ * transaction is done and the new `packed-refs` file is activated.
*/
struct packed_ref_store {
struct ref_store base;
@@ -91,10 +127,10 @@ struct packed_ref_store {
char *path;
/*
- * A cache of the values read from the `packed-refs` file, if
- * it might still be current; otherwise, NULL.
+ * A snapshot of the values read from the `packed-refs` file,
+ * if it might still be current; otherwise, NULL.
*/
- struct packed_ref_cache *cache;
+ struct snapshot *snapshot;
/*
* Lock used for the "packed-refs" file. Note that this (and
@@ -111,43 +147,42 @@ struct packed_ref_store {
};
/*
- * Increment the reference count of *packed_refs.
+ * Increment the reference count of `*snapshot`.
*/
-static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
+static void acquire_snapshot(struct snapshot *snapshot)
{
- packed_refs->referrers++;
+ snapshot->referrers++;
}
/*
- * If the buffer in `packed_refs` is active, then either munmap the
+ * If the buffer in `snapshot` is active, then either munmap the
* memory and close the file, or free the memory. Then set the buffer
* pointers to NULL.
*/
-static void release_packed_ref_buffer(struct packed_ref_cache *packed_refs)
+static void clear_snapshot_buffer(struct snapshot *snapshot)
{
- if (packed_refs->mmapped) {
- if (munmap(packed_refs->buf,
- packed_refs->eof - packed_refs->buf))
+ if (snapshot->mmapped) {
+ if (munmap(snapshot->buf, snapshot->eof - snapshot->buf))
die_errno("error ummapping packed-refs file %s",
- packed_refs->refs->path);
- packed_refs->mmapped = 0;
+ snapshot->refs->path);
+ snapshot->mmapped = 0;
} else {
- free(packed_refs->buf);
+ free(snapshot->buf);
}
- packed_refs->buf = packed_refs->eof = NULL;
- packed_refs->header_len = 0;
+ snapshot->buf = snapshot->eof = NULL;
+ snapshot->header_len = 0;
}
/*
- * Decrease the reference count of *packed_refs. If it goes to zero,
- * free *packed_refs and return true; otherwise return false.
+ * Decrease the reference count of `*snapshot`. If it goes to zero,
+ * free `*snapshot` and return true; otherwise return false.
*/
-static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
+static int release_snapshot(struct snapshot *snapshot)
{
- if (!--packed_refs->referrers) {
- stat_validity_clear(&packed_refs->validity);
- release_packed_ref_buffer(packed_refs);
- free(packed_refs);
+ if (!--snapshot->referrers) {
+ stat_validity_clear(&snapshot->validity);
+ clear_snapshot_buffer(snapshot);
+ free(snapshot);
return 1;
} else {
return 0;
@@ -192,13 +227,13 @@ static struct packed_ref_store *packed_downcast(struct
ref_store *ref_store,
return refs;
}
-static void clear_packed_ref_cache(struct packed_ref_store *refs)
+static void clear_snapshot(struct packed_ref_store *refs)
{
- if (refs->cache) {
- struct packed_ref_cache *cache = refs->cache;
+ if (refs->snapshot) {
+ struct snapshot *snapshot = refs->snapshot;
- refs->cache = NULL;
- release_packed_ref_cache(cache);
+ refs->snapshot = NULL;
+ release_snapshot(snapshot);
}
}
@@ -225,14 +260,14 @@ static NORETURN void die_invalid_line(const char *path,
}
-struct packed_ref_entry {
+struct snapshot_record {
const char *start;
size_t len;
};
-static int cmp_packed_ref_entries(const void *v1, const void *v2)
+static int cmp_packed_ref_records(const void *v1, const void *v2)
{
- const struct packed_ref_entry *e1 = v1, *e2 = v2;
+ const struct snapshot_record *e1 = v1, *e2 = v2;
const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1;
const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1;
@@ -251,10 +286,10 @@ static int cmp_packed_ref_entries(const void *v1, const
void *v2)
}
/*
- * Compare a packed-refs record pointed to by `rec` to the specified
- * NUL-terminated refname.
+ * Compare a snapshot record at `rec` to the specified NUL-terminated
+ * refname.
*/
-static int cmp_entry_to_refname(const char *rec, const char *refname)
+static int cmp_record_to_refname(const char *rec, const char *refname)
{
const char *r1 = rec + GIT_SHA1_HEXSZ + 1;
const char *r2 = refname;
@@ -272,31 +307,30 @@ static int cmp_entry_to_refname(const char *rec, const
char *refname)
}
/*
- * `packed_refs->buf` is not known to be sorted. Check whether it is,
- * and if not, sort it into new memory and munmap/free the old
- * storage.
+ * `snapshot->buf` is not known to be sorted. Check whether it is, and
+ * if not, sort it into new memory and munmap/free the old storage.
*/
-static void sort_packed_refs(struct packed_ref_cache *packed_refs)
+static void sort_snapshot(struct snapshot *snapshot)
{
- struct packed_ref_entry *entries = NULL;
+ struct snapshot_record *records = NULL;
size_t alloc = 0, nr = 0;
int sorted = 1;
const char *pos, *eof, *eol;
size_t len, i;
char *new_buffer, *dst;
- pos = packed_refs->buf + packed_refs->header_len;
- eof = packed_refs->eof;
+ pos = snapshot->buf + snapshot->header_len;
+ eof = snapshot->eof;
len = eof - pos;
if (!len)
return;
/*
- * Initialize entries based on a crude estimate of the number
+ * Initialize records based on a crude estimate of the number
* of references in the file (we'll grow it below if needed):
*/
- ALLOC_GROW(entries, len / 80 + 20, alloc);
+ ALLOC_GROW(records, len / 80 + 20, alloc);
while (pos < eof) {
eol = memchr(pos, '\n', eof - pos);
@@ -304,7 +338,7 @@ static void sort_packed_refs(struct packed_ref_cache
*packed_refs)
/* The safety check should prevent this. */
BUG("unterminated line found in packed-refs");
if (eol - pos < GIT_SHA1_HEXSZ + 2)
- die_invalid_line(packed_refs->refs->path,
+ die_invalid_line(snapshot->refs->path,
pos, eof - pos);
eol++;
if (eol < eof && *eol == '^') {
@@ -321,15 +355,15 @@ static void sort_packed_refs(struct packed_ref_cache
*packed_refs)
eol++;
}
- ALLOC_GROW(entries, nr + 1, alloc);
- entries[nr].start = pos;
- entries[nr].len = eol - pos;
+ ALLOC_GROW(records, nr + 1, alloc);
+ records[nr].start = pos;
+ records[nr].len = eol - pos;
nr++;
if (sorted &&
nr > 1 &&
- cmp_packed_ref_entries(&entries[nr - 2],
- &entries[nr - 1]) >= 0)
+ cmp_packed_ref_records(&records[nr - 2],
+ &records[nr - 1]) >= 0)
sorted = 0;
pos = eol;
@@ -338,31 +372,31 @@ static void sort_packed_refs(struct packed_ref_cache
*packed_refs)
if (sorted)
goto cleanup;
- /* We need to sort the memory. First we sort the entries array: */
- QSORT(entries, nr, cmp_packed_ref_entries);
+ /* We need to sort the memory. First we sort the records array: */
+ QSORT(records, nr, cmp_packed_ref_records);
/*
* Allocate a new chunk of memory, and copy the old memory to
- * the new in the order indicated by `entries` (not bothering
+ * the new in the order indicated by `records` (not bothering
* with the header line):
*/
new_buffer = xmalloc(len);
for (dst = new_buffer, i = 0; i < nr; i++) {
- memcpy(dst, entries[i].start, entries[i].len);
- dst += entries[i].len;
+ memcpy(dst, records[i].start, records[i].len);
+ dst += records[i].len;
}
/*
* Now munmap the old buffer and use the sorted buffer in its
* place:
*/
- release_packed_ref_buffer(packed_refs);
- packed_refs->buf = new_buffer;
- packed_refs->eof = new_buffer + len;
- packed_refs->header_len = 0;
+ clear_snapshot_buffer(snapshot);
+ snapshot->buf = new_buffer;
+ snapshot->eof = new_buffer + len;
+ snapshot->header_len = 0;
cleanup:
- free(entries);
+ free(records);
}
/*
@@ -406,10 +440,10 @@ static const char *find_end_of_record(const char *p,
const char *end)
* (GIT_SHA1_HEXSZ + 1) characters before the LF. Die if either of
* these checks fails.
*/
-static void verify_buffer_safe(struct packed_ref_cache *packed_refs)
+static void verify_buffer_safe(struct snapshot *snapshot)
{
- const char *buf = packed_refs->buf + packed_refs->header_len;
- const char *eof = packed_refs->eof;
+ const char *buf = snapshot->buf + snapshot->header_len;
+ const char *eof = snapshot->eof;
const char *last_line;
if (buf == eof)
@@ -417,24 +451,23 @@ static void verify_buffer_safe(struct packed_ref_cache
*packed_refs)
last_line = find_start_of_record(buf, eof - 1);
if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2)
- die_invalid_line(packed_refs->refs->path,
+ die_invalid_line(snapshot->refs->path,
last_line, eof - last_line);
}
/*
* Depending on `mmap_strategy`, either mmap or read the contents of
- * the `packed-refs` file into the `packed_refs` instance. Return 1 if
- * the file existed and was read, or 0 if the file was absent. Die on
- * errors.
+ * the `packed-refs` file into the snapshot. Return 1 if the file
+ * existed and was read, or 0 if the file was absent. Die on errors.
*/
-static int load_contents(struct packed_ref_cache *packed_refs)
+static int load_contents(struct snapshot *snapshot)
{
int fd;
struct stat st;
size_t size;
ssize_t bytes_read;
- fd = open(packed_refs->refs->path, O_RDONLY);
+ fd = open(snapshot->refs->path, O_RDONLY);
if (fd < 0) {
if (errno == ENOENT) {
/*
@@ -446,30 +479,30 @@ static int load_contents(struct packed_ref_cache
*packed_refs)
*/
return 0;
} else {
- die_errno("couldn't read %s", packed_refs->refs->path);
+ die_errno("couldn't read %s", snapshot->refs->path);
}
}
- stat_validity_update(&packed_refs->validity, fd);
+ stat_validity_update(&snapshot->validity, fd);
if (fstat(fd, &st) < 0)
- die_errno("couldn't stat %s", packed_refs->refs->path);
+ die_errno("couldn't stat %s", snapshot->refs->path);
size = xsize_t(st.st_size);
switch (mmap_strategy) {
case MMAP_NONE:
- packed_refs->buf = xmalloc(size);
- bytes_read = read_in_full(fd, packed_refs->buf, size);
+ snapshot->buf = xmalloc(size);
+ bytes_read = read_in_full(fd, snapshot->buf, size);
if (bytes_read < 0 || bytes_read != size)
- die_errno("couldn't read %s", packed_refs->refs->path);
- packed_refs->eof = packed_refs->buf + size;
- packed_refs->mmapped = 0;
+ die_errno("couldn't read %s", snapshot->refs->path);
+ snapshot->eof = snapshot->buf + size;
+ snapshot->mmapped = 0;
break;
case MMAP_TEMPORARY:
case MMAP_OK:
- packed_refs->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE,
fd, 0);
- packed_refs->eof = packed_refs->buf + size;
- packed_refs->mmapped = 1;
+ snapshot->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd,
0);
+ snapshot->eof = snapshot->buf + size;
+ snapshot->mmapped = 1;
break;
}
close(fd);
@@ -478,7 +511,7 @@ static int load_contents(struct packed_ref_cache
*packed_refs)
}
/*
- * Find the place in `cache->buf` where the start of the record for
+ * Find the place in `snapshot->buf` where the start of the record for
* `refname` starts. If `mustexist` is true and the reference doesn't
* exist, then return NULL. If `mustexist` is false and the reference
* doesn't exist, then return the point where that reference would be
@@ -486,10 +519,10 @@ static int load_contents(struct packed_ref_cache
*packed_refs)
* reference name; for example, one could search for "refs/replace/"
* to find the start of any replace references.
*
- * The record is sought using a binary search, so `cache->buf` must be
- * sorted.
+ * The record is sought using a binary search, so `snapshot->buf` must
+ * be sorted.
*/
-static const char *find_reference_location(struct packed_ref_cache *cache,
+static const char *find_reference_location(struct snapshot *snapshot,
const char *refname, int mustexist)
{
/*
@@ -506,13 +539,13 @@ static const char *find_reference_location(struct
packed_ref_cache *cache,
* preceding records all have reference names that come
* *before* `refname`.
*/
- const char *lo = cache->buf + cache->header_len;
+ const char *lo = snapshot->buf + snapshot->header_len;
/*
* A pointer to a the first character of a record whose
* reference name comes *after* `refname`.
*/
- const char *hi = cache->eof;
+ const char *hi = snapshot->eof;
while (lo < hi) {
const char *mid, *rec;
@@ -520,7 +553,7 @@ static const char *find_reference_location(struct
packed_ref_cache *cache,
mid = lo + (hi - lo) / 2;
rec = find_start_of_record(lo, mid);
- cmp = cmp_entry_to_refname(rec, refname);
+ cmp = cmp_record_to_refname(rec, refname);
if (cmp < 0) {
lo = find_end_of_record(mid, hi);
} else if (cmp > 0) {
@@ -537,9 +570,9 @@ static const char *find_reference_location(struct
packed_ref_cache *cache,
}
/*
- * Read from the `packed-refs` file into a newly-allocated
- * `packed_ref_cache` and return it. The return value will already
- * have its reference count incremented.
+ * Create a newly-allocated `snapshot` of the `packed-refs` file in
+ * its current state and return it. The return value will already have
+ * its reference count incremented.
*
* A comment line of the form "# pack-refs with: " may contain zero or
* more traits. We interpret the traits as follows:
@@ -569,116 +602,117 @@ static const char *find_reference_location(struct
packed_ref_cache *cache,
*
* The references in this file are known to be sorted by refname.
*/
-static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
+static struct snapshot *create_snapshot(struct packed_ref_store *refs)
{
- struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
+ struct snapshot *snapshot = xcalloc(1, sizeof(*snapshot));
int sorted = 0;
- packed_refs->refs = refs;
- acquire_packed_ref_cache(packed_refs);
- packed_refs->peeled = PEELED_NONE;
+ snapshot->refs = refs;
+ acquire_snapshot(snapshot);
+ snapshot->peeled = PEELED_NONE;
- if (!load_contents(packed_refs))
- return packed_refs;
+ if (!load_contents(snapshot))
+ return snapshot;
/* If the file has a header line, process it: */
- if (packed_refs->buf < packed_refs->eof && *packed_refs->buf == '#') {
+ if (snapshot->buf < snapshot->eof && *snapshot->buf == '#') {
struct strbuf tmp = STRBUF_INIT;
char *p;
const char *eol;
struct string_list traits = STRING_LIST_INIT_NODUP;
- eol = memchr(packed_refs->buf, '\n',
- packed_refs->eof - packed_refs->buf);
+ eol = memchr(snapshot->buf, '\n',
+ snapshot->eof - snapshot->buf);
if (!eol)
die_unterminated_line(refs->path,
- packed_refs->buf,
- packed_refs->eof -
packed_refs->buf);
+ snapshot->buf,
+ snapshot->eof - snapshot->buf);
- strbuf_add(&tmp, packed_refs->buf, eol - packed_refs->buf);
+ strbuf_add(&tmp, snapshot->buf, eol - snapshot->buf);
if (!skip_prefix(tmp.buf, "# pack-refs with:", (const char
**)&p))
die_invalid_line(refs->path,
- packed_refs->buf,
- packed_refs->eof - packed_refs->buf);
+ snapshot->buf,
+ snapshot->eof - snapshot->buf);
string_list_split_in_place(&traits, p, ' ', -1);
if (unsorted_string_list_has_string(&traits, "fully-peeled"))
- packed_refs->peeled = PEELED_FULLY;
+ snapshot->peeled = PEELED_FULLY;
else if (unsorted_string_list_has_string(&traits, "peeled"))
- packed_refs->peeled = PEELED_TAGS;
+ snapshot->peeled = PEELED_TAGS;
sorted = unsorted_string_list_has_string(&traits, "sorted");
/* perhaps other traits later as well */
/* The "+ 1" is for the LF character. */
- packed_refs->header_len = eol + 1 - packed_refs->buf;
+ snapshot->header_len = eol + 1 - snapshot->buf;
string_list_clear(&traits, 0);
strbuf_release(&tmp);
}
- verify_buffer_safe(packed_refs);
+ verify_buffer_safe(snapshot);
if (!sorted) {
- sort_packed_refs(packed_refs);
+ sort_snapshot(snapshot);
/*
* Reordering the records might have moved a short one
* to the end of the buffer, so verify the buffer's
* safety again:
*/
- verify_buffer_safe(packed_refs);
+ verify_buffer_safe(snapshot);
}
- if (mmap_strategy != MMAP_OK && packed_refs->mmapped) {
+ if (mmap_strategy != MMAP_OK && snapshot->mmapped) {
/*
* We don't want to leave the file mmapped, so we are
* forced to make a copy now:
*/
- size_t size = packed_refs->eof -
- (packed_refs->buf + packed_refs->header_len);
+ size_t size = snapshot->eof -
+ (snapshot->buf + snapshot->header_len);
char *buf_copy = xmalloc(size);
- memcpy(buf_copy, packed_refs->buf + packed_refs->header_len,
size);
- release_packed_ref_buffer(packed_refs);
- packed_refs->buf = buf_copy;
- packed_refs->eof = buf_copy + size;
+ memcpy(buf_copy, snapshot->buf + snapshot->header_len, size);
+ clear_snapshot_buffer(snapshot);
+ snapshot->buf = buf_copy;
+ snapshot->eof = buf_copy + size;
}
- return packed_refs;
+ return snapshot;
}
/*
- * Check that the packed refs cache (if any) still reflects the
- * contents of the file. If not, clear the cache.
+ * Check that `refs->snapshot` (if present) still reflects the
+ * contents of the `packed-refs` file. If not, clear the snapshot.
*/
-static void validate_packed_ref_cache(struct packed_ref_store *refs)
+static void validate_snapshot(struct packed_ref_store *refs)
{
- if (refs->cache &&
- !stat_validity_check(&refs->cache->validity, refs->path))
- clear_packed_ref_cache(refs);
+ if (refs->snapshot &&
+ !stat_validity_check(&refs->snapshot->validity, refs->path))
+ clear_snapshot(refs);
}
/*
- * Get the packed_ref_cache for the specified packed_ref_store,
- * creating and populating it if it hasn't been read before or if the
- * file has been changed (according to its `validity` field) since it
- * was last read. On the other hand, if we hold the lock, then assume
- * that the file hasn't been changed out from under us, so skip the
- * extra `stat()` call in `stat_validity_check()`.
+ * Get the `snapshot` for the specified packed_ref_store, creating and
+ * populating it if it hasn't been read before or if the file has been
+ * changed (according to its `validity` field) since it was last read.
+ * On the other hand, if we hold the lock, then assume that the file
+ * hasn't been changed out from under us, so skip the extra `stat()`
+ * call in `stat_validity_check()`. This function does *not* increase
+ * the snapshot's reference count on behalf of the caller.
*/
-static struct packed_ref_cache *get_packed_ref_cache(struct packed_ref_store
*refs)
+static struct snapshot *get_snapshot(struct packed_ref_store *refs)
{
if (!is_lock_file_locked(&refs->lock))
- validate_packed_ref_cache(refs);
+ validate_snapshot(refs);
- if (!refs->cache)
- refs->cache = read_packed_refs(refs);
+ if (!refs->snapshot)
+ refs->snapshot = create_snapshot(refs);
- return refs->cache;
+ return refs->snapshot;
}
static int packed_read_raw_ref(struct ref_store *ref_store,
@@ -687,12 +721,12 @@ static int packed_read_raw_ref(struct ref_store
*ref_store,
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
- struct packed_ref_cache *packed_refs = get_packed_ref_cache(refs);
+ struct snapshot *snapshot = get_snapshot(refs);
const char *rec;
*type = 0;
- rec = find_reference_location(packed_refs, refname, 1);
+ rec = find_reference_location(snapshot, refname, 1);
if (!rec) {
/* refname is not a packed reference. */
@@ -701,7 +735,7 @@ static int packed_read_raw_ref(struct ref_store *ref_store,
}
if (get_sha1_hex(rec, sha1))
- die_invalid_line(refs->path, rec, packed_refs->eof - rec);
+ die_invalid_line(refs->path, rec, snapshot->eof - rec);
*type = REF_ISPACKED;
return 0;
@@ -716,26 +750,33 @@ static int packed_read_raw_ref(struct ref_store
*ref_store,
#define REF_KNOWS_PEELED 0x40
/*
- * An iterator over a packed-refs file that is currently mmapped.
+ * An iterator over a snapshot of a `packed-refs` file.
*/
struct packed_ref_iterator {
struct ref_iterator base;
- struct packed_ref_cache *packed_refs;
+ struct snapshot *snapshot;
- /* The current position in the mmapped file: */
+ /* The current position in the snapshot's buffer: */
const char *pos;
- /* The end of the mmapped file: */
+ /* The end of the part of the buffer that will be iterated over: */
const char *eof;
+ /* Scratch space for current values: */
struct object_id oid, peeled;
-
struct strbuf refname_buf;
unsigned int flags;
};
+/*
+ * Move the iterator to the next record in the snapshot, without
+ * respect for whether the record is actually required by the current
+ * iteration. Adjust the fields in `iter` and return `ITER_OK` or
+ * `ITER_DONE`. This function does not free the iterator in the case
+ * of `ITER_DONE`.
+ */
static int next_record(struct packed_ref_iterator *iter)
{
const char *p = iter->pos, *eol;
@@ -750,12 +791,12 @@ static int next_record(struct packed_ref_iterator *iter)
if (iter->eof - p < GIT_SHA1_HEXSZ + 2 ||
parse_oid_hex(p, &iter->oid, &p) ||
!isspace(*p++))
- die_invalid_line(iter->packed_refs->refs->path,
+ die_invalid_line(iter->snapshot->refs->path,
iter->pos, iter->eof - iter->pos);
eol = memchr(p, '\n', iter->eof - p);
if (!eol)
- die_unterminated_line(iter->packed_refs->refs->path,
+ die_unterminated_line(iter->snapshot->refs->path,
iter->pos, iter->eof - iter->pos);
strbuf_add(&iter->refname_buf, p, eol - p);
@@ -768,8 +809,8 @@ static int next_record(struct packed_ref_iterator *iter)
oidclr(&iter->oid);
iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN;
}
- if (iter->packed_refs->peeled == PEELED_FULLY ||
- (iter->packed_refs->peeled == PEELED_TAGS &&
+ if (iter->snapshot->peeled == PEELED_FULLY ||
+ (iter->snapshot->peeled == PEELED_TAGS &&
starts_with(iter->base.refname, "refs/tags/")))
iter->base.flags |= REF_KNOWS_PEELED;
@@ -780,7 +821,7 @@ static int next_record(struct packed_ref_iterator *iter)
if (iter->eof - p < GIT_SHA1_HEXSZ + 1 ||
parse_oid_hex(p, &iter->peeled, &p) ||
*p++ != '\n')
- die_invalid_line(iter->packed_refs->refs->path,
+ die_invalid_line(iter->snapshot->refs->path,
iter->pos, iter->eof - iter->pos);
iter->pos = p;
@@ -850,7 +891,7 @@ static int packed_ref_iterator_abort(struct ref_iterator
*ref_iterator)
int ok = ITER_DONE;
strbuf_release(&iter->refname_buf);
- release_packed_ref_cache(iter->packed_refs);
+ release_snapshot(iter->snapshot);
base_ref_iterator_free(ref_iterator);
return ok;
}
@@ -866,7 +907,7 @@ static struct ref_iterator *packed_ref_iterator_begin(
const char *prefix, unsigned int flags)
{
struct packed_ref_store *refs;
- struct packed_ref_cache *packed_refs;
+ struct snapshot *snapshot;
const char *start;
struct packed_ref_iterator *iter;
struct ref_iterator *ref_iterator;
@@ -876,30 +917,30 @@ static struct ref_iterator *packed_ref_iterator_begin(
required_flags |= REF_STORE_ODB;
refs = packed_downcast(ref_store, required_flags, "ref_iterator_begin");
- packed_refs = get_packed_ref_cache(refs);
+ /*
+ * Note that `get_snapshot()` internally checks whether the
+ * snapshot is up to date with what is on disk, and re-reads
+ * it if not.
+ */
+ snapshot = get_snapshot(refs);
- if (!packed_refs->buf)
+ if (!snapshot->buf)
return empty_ref_iterator_begin();
iter = xcalloc(1, sizeof(*iter));
ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1);
- /*
- * Note that get_packed_ref_cache() internally checks whether
- * the packed-ref cache is up to date with what is on disk,
- * and re-reads it if not.
- */
- iter->packed_refs = packed_refs;
- acquire_packed_ref_cache(packed_refs);
+ iter->snapshot = snapshot;
+ acquire_snapshot(snapshot);
if (prefix && *prefix)
- start = find_reference_location(packed_refs, prefix, 0);
+ start = find_reference_location(snapshot, prefix, 0);
else
- start = packed_refs->buf + packed_refs->header_len;
+ start = snapshot->buf + snapshot->header_len;
iter->pos = start;
- iter->eof = packed_refs->eof;
+ iter->eof = snapshot->eof;
strbuf_init(&iter->refname_buf, 0);
iter->base.oid = &iter->oid;
@@ -963,19 +1004,19 @@ int packed_refs_lock(struct ref_store *ref_store, int
flags, struct strbuf *err)
/*
* Now that we hold the `packed-refs` lock, make sure that our
- * cache matches the current version of the file. Normally
- * `get_packed_ref_cache()` does that for us, but that
- * function assumes that when the file is locked, any existing
- * cache is still valid. We've just locked the file, but it
- * might have changed the moment *before* we locked it.
+ * snapshot matches the current version of the file. Normally
+ * `get_snapshot()` does that for us, but that function
+ * assumes that when the file is locked, any existing snapshot
+ * is still valid. We've just locked the file, but it might
+ * have changed the moment *before* we locked it.
*/
- validate_packed_ref_cache(refs);
+ validate_snapshot(refs);
/*
* Now make sure that the packed-refs file as it exists in the
- * locked state is loaded into the cache:
+ * locked state is loaded into the snapshot:
*/
- get_packed_ref_cache(refs);
+ get_snapshot(refs);
return 0;
}
@@ -1002,8 +1043,8 @@ int packed_refs_is_locked(struct ref_store *ref_store)
}
/*
- * The packed-refs header line that we write out. Perhaps other
- * traits will be added later.
+ * The packed-refs header line that we write out. Perhaps other traits
+ * will be added later.
*
* Note that earlier versions of Git used to parse these traits by
* looking for " trait " in the line. For this reason, the space after
@@ -1019,9 +1060,9 @@ static int packed_init_db(struct ref_store *ref_store,
struct strbuf *err)
}
/*
- * Write the packed-refs from the cache to the packed-refs tempfile,
- * incorporating any changes from `updates`. `updates` must be a
- * sorted string list whose keys are the refnames and whose util
+ * Write the packed refs from the current snapshot to the packed-refs
+ * tempfile, incorporating any changes from `updates`. `updates` must
+ * be a sorted string list whose keys are the refnames and whose util
* values are `struct ref_update *`. On error, rollback the tempfile,
* write an error message to `err`, and return a nonzero value.
*
@@ -1262,9 +1303,10 @@ static int packed_transaction_prepare(struct ref_store
*ref_store,
/*
* Note that we *don't* skip transactions with zero updates,
* because such a transaction might be executed for the side
- * effect of ensuring that all of the references are peeled.
- * If the caller wants to optimize away empty transactions, it
- * should do so itself.
+ * effect of ensuring that all of the references are peeled or
+ * ensuring that the `packed-refs` file is sorted. If the
+ * caller wants to optimize away empty transactions, it should
+ * do so itself.
*/
data = xcalloc(1, sizeof(*data));
@@ -1330,7 +1372,7 @@ static int packed_transaction_finish(struct ref_store
*ref_store,
int ret = TRANSACTION_GENERIC_ERROR;
char *packed_refs_path;
- clear_packed_ref_cache(refs);
+ clear_snapshot(refs);
packed_refs_path = get_locked_file_path(&refs->lock);
if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
--
2.14.1
