Re: [PATCH v2 10/20] ref-cache: introduce a new type, ref_cache

[Michael Haggerty]

On 04/07/2017 01:32 PM, Duy Nguyen wrote:
> On Fri, Mar 31, 2017 at 9:11 PM, Michael Haggerty  
> wrote:
>> +void free_ref_cache(struct ref_cache *cache)
>> +{
>> +   free_ref_entry(cache->root);
>> +   free(cache);
>> +}
> 
> free(NULL) is no-op (and safe). Maybe we should follow the same
> pattern for free_ref_cache(). It's really up to you.

If I look at other `free_*()` functions in our codebase, it doesn't seem
that many of them handle NULL, and that feature wouldn't help the
callers of this function. So I think I'll leave it the way that it is.

Michael

Re: [PATCH v2 10/20] ref-cache: introduce a new type, ref_cache

[Duy Nguyen]

On Fri, Mar 31, 2017 at 9:11 PM, Michael Haggerty  wrote:
> +void free_ref_cache(struct ref_cache *cache)
> +{
> +   free_ref_entry(cache->root);
> +   free(cache);
> +}

free(NULL) is no-op (and safe). Maybe we should follow the same
pattern for free_ref_cache(). It's really up to you.
-- 
Duy

[PATCH v2 10/20] ref-cache: introduce a new type, ref_cache

[Michael Haggerty]

For now, it just wraps a `ref_entry *` that points at the root of the
tree. Soon it will hold more information.

Add two new functions, `create_ref_cache()` and `free_ref_cache()`.
Make `free_ref_entry()` private.

Change files-backend to use this type to hold its caches.

Signed-off-by: Michael Haggerty 
---
 refs/files-backend.c | 28 +---
 refs/ref-cache.c | 16 +++-
 refs/ref-cache.h | 15 ++-
 3 files changed, 46 insertions(+), 13 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index f07e93d522..a7d912ae39 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -44,7 +44,7 @@ static int entry_resolves_to_object(struct ref_entry *entry)
 }
 
 struct packed_ref_cache {
-   struct ref_entry *root;
+   struct ref_cache *cache;
 
/*
 * Count of references to the data structure in this instance,
@@ -79,7 +79,7 @@ struct files_ref_store {
char *gitcommondir;
char *packed_refs_path;
 
-   struct ref_entry *loose;
+   struct ref_cache *loose;
struct packed_ref_cache *packed;
 };
 
@@ -101,7 +101,7 @@ static void acquire_packed_ref_cache(struct 
packed_ref_cache *packed_refs)
 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
 {
if (!--packed_refs->referrers) {
-   free_ref_entry(packed_refs->root);
+   free_ref_cache(packed_refs->cache);
stat_validity_clear(_refs->validity);
free(packed_refs);
return 1;
@@ -125,7 +125,7 @@ static void clear_packed_ref_cache(struct files_ref_store 
*refs)
 static void clear_loose_ref_cache(struct files_ref_store *refs)
 {
if (refs->loose) {
-   free_ref_entry(refs->loose);
+   free_ref_cache(refs->loose);
refs->loose = NULL;
}
 }
@@ -387,11 +387,12 @@ static struct packed_ref_cache 
*get_packed_ref_cache(struct files_ref_store *ref
 
refs->packed = xcalloc(1, sizeof(*refs->packed));
acquire_packed_ref_cache(refs->packed);
-   refs->packed->root = create_dir_entry(refs, "", 0, 0);
+   refs->packed->cache = create_ref_cache(refs);
+   refs->packed->cache->root->flag &= ~REF_INCOMPLETE;
f = fopen(packed_refs_file, "r");
if (f) {
stat_validity_update(>packed->validity, 
fileno(f));
-   read_packed_refs(f, get_ref_dir(refs->packed->root));
+   read_packed_refs(f, 
get_ref_dir(refs->packed->cache->root));
fclose(f);
}
}
@@ -400,7 +401,7 @@ static struct packed_ref_cache *get_packed_ref_cache(struct 
files_ref_store *ref
 
 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache 
*packed_ref_cache)
 {
-   return get_ref_dir(packed_ref_cache->root);
+   return get_ref_dir(packed_ref_cache->cache->root);
 }
 
 static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
@@ -515,14 +516,19 @@ static struct ref_dir *get_loose_refs(struct 
files_ref_store *refs)
 * are about to read the only subdirectory that can
 * hold references:
 */
-   refs->loose = create_dir_entry(refs, "", 0, 0);
+   refs->loose = create_ref_cache(refs);
+
+   /* We're going to fill the top level ourselves: */
+   refs->loose->root->flag &= ~REF_INCOMPLETE;
+
/*
-* Create an incomplete entry for "refs/":
+* Add an incomplete entry for "refs/" (to be filled
+* lazily):
 */
-   add_entry_to_dir(get_ref_dir(refs->loose),
+   add_entry_to_dir(get_ref_dir(refs->loose->root),
 create_dir_entry(refs, "refs/", 5, 1));
}
-   return get_ref_dir(refs->loose);
+   return get_ref_dir(refs->loose->root);
 }
 
 /*
diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index 4274a43a9b..bf911028c8 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -63,9 +63,17 @@ struct ref_entry *create_ref_entry(const char *refname,
return ref;
 }
 
+struct ref_cache *create_ref_cache(struct files_ref_store *refs)
+{
+   struct ref_cache *ret = xcalloc(1, sizeof(*ret));
+
+   ret->root = create_dir_entry(refs, "", 0, 1);
+   return ret;
+}
+
 static void clear_ref_dir(struct ref_dir *dir);
 
-void free_ref_entry(struct ref_entry *entry)
+static void free_ref_entry(struct ref_entry *entry)
 {
if (entry->flag & REF_DIR) {
/*
@@ -77,6 +85,12 @@ void free_ref_entry(struct ref_entry *entry)
free(entry);
 }
 
+void free_ref_cache(struct ref_cache *cache)
+{
+   free_ref_entry(cache->root);
+   free(cache);
+}
+
 /*
  * Clear and free all entries in dir, recursively.
  */
diff --git a/refs/ref-cache.h