mru: Replace mru.[ch] with list.h implementationgs/retire-mru

Replace the custom calls to mru.[ch] with calls to list.h. This patch is
the final step in removing the mru API completely and inlining the logic.
This patch leads to significant code reduction and the mru API hence, is
not a useful abstraction anymore.

Signed-off-by: Gargi Sharma <gs051095@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

7 files changed, 17 insertions, 86 deletions

diff --git a/Makefile b/Makefile
index ed4ca438bd..4a79ec5012 100644
--- a/Makefile
+++ b/Makefile
@@ -814,7 +814,6 @@ LIB_OBJS += merge.o
 LIB_OBJS += merge-blobs.o
 LIB_OBJS += merge-recursive.o
 LIB_OBJS += mergesort.o
-LIB_OBJS += mru.o
 LIB_OBJS += name-hash.o
 LIB_OBJS += notes.o
 LIB_OBJS += notes-cache.o
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index ba812349e0..6a0b8e8b9c 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -24,7 +24,7 @@
 #include "reachable.h"
 #include "sha1-array.h"
 #include "argv-array.h"
-#include "mru.h"
+#include "list.h"
 #include "packfile.h"
 
 static const char *pack_usage[] = {
@@ -1012,9 +1012,8 @@ static int want_object_in_pack(const unsigned char *sha1,
 			return want;
 	}
 
-	list_for_each(pos, &packed_git_mru.list) {
-		struct mru *entry = list_entry(pos, struct mru, list);
-		struct packed_git *p = entry->item;
+	list_for_each(pos, &packed_git_mru) {
+		struct packed_git *p = list_entry(pos, struct packed_git, mru);
 		off_t offset;
 
 		if (p == *found_pack)
@@ -1031,7 +1030,7 @@ static int want_object_in_pack(const unsigned char *sha1,
 			}
 			want = want_found_object(exclude, p);
 			if (!exclude && want > 0)
-				mru_mark(&packed_git_mru, entry);
+				list_move(&p->mru, &packed_git_mru);
 			if (want != -1)
 				return want;
 		}
diff --git a/cache.h b/cache.h
index 49b083ee0a..cc09e3b652 100644
--- a/cache.h
+++ b/cache.h
@@ -4,7 +4,7 @@
 #include "git-compat-util.h"
 #include "strbuf.h"
 #include "hashmap.h"
-#include "mru.h"
+#include "list.h"
 #include "advice.h"
 #include "gettext.h"
 #include "convert.h"
@@ -1566,6 +1566,7 @@ struct pack_window {
 
 extern struct packed_git {
 	struct packed_git *next;
+	struct list_head mru;
 	struct pack_window *windows;
 	off_t pack_size;
 	const void *index_data;
@@ -1587,10 +1588,9 @@ extern struct packed_git {
 } *packed_git;
 
 /*
- * A most-recently-used ordered version of the packed_git list, which can
- * be iterated instead of packed_git (and marked via mru_mark).
+ * A most-recently-used ordered version of the packed_git list.
  */
-extern struct mru packed_git_mru;
+extern struct list_head packed_git_mru;
 
 struct pack_entry {
 	off_t offset;
diff --git a/mru.c b/mru.c
deleted file mode 100644
index 8f3f34c5ba..0000000000
--- a/mru.c
+++ /dev/null
@@ -1,27 +0,0 @@
-#include "cache.h"
-#include "mru.h"
-
-void mru_append(struct mru *head, void *item)
-{
-	struct mru *cur = xmalloc(sizeof(*cur));
-	cur->item = item;
-	list_add_tail(&cur->list, &head->list);
-}
-
-void mru_mark(struct mru *head, struct mru *entry)
-{
-	/* To mark means to put at the front of the list. */
-	list_del(&entry->list);
-	list_add(&entry->list, &head->list);
-}
-
-void mru_clear(struct mru *head)
-{
-	struct list_head *pos;
-	struct list_head *tmp;
-
-	list_for_each_safe(pos, tmp, &head->list) {
-		free(list_entry(pos, struct mru, list));
-	}
-	INIT_LIST_HEAD(&head->list);
-}
diff --git a/mru.h b/mru.h
deleted file mode 100644
index 80a589eb4c..0000000000
--- a/mru.h
+++ /dev/null
@@ -1,40 +0,0 @@
-#ifndef MRU_H
-#define MRU_H
-
-#include "list.h"
-
-/**
- * A simple most-recently-used cache, backed by a doubly-linked list.
- *
- * Usage is roughly:
- *
- *   // Create a list.  Zero-initialization is required.
- *   static struct mru cache;
- *   INIT_LIST_HEAD(&cache.list);
- *
- *   // Add new item to the end of the list.
- *   void *item;
- *   ...
- *   mru_append(&cache, item);
- *
- *   // Mark an item as used, moving it to the front of the list.
- *   mru_mark(&cache, item);
- *
- *   // Reset the list to empty, cleaning up all resources.
- *   mru_clear(&cache);
- *
- * Note that you SHOULD NOT call mru_mark() and then continue traversing the
- * list; it reorders the marked item to the front of the list, and therefore
- * you will begin traversing the whole list again.
- */
-
-struct mru {
-	struct list_head list;
-	void *item;
-};
-
-void mru_append(struct mru *head, void *item);
-void mru_mark(struct mru *head, struct mru *entry);
-void mru_clear(struct mru *head);
-
-#endif /* MRU_H */
diff --git a/packfile.c b/packfile.c
index 502d915991..8d3bd5fcb3 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1,5 +1,5 @@
 #include "cache.h"
-#include "mru.h"
+#include "list.h"
 #include "pack.h"
 #include "dir.h"
 #include "mergesort.h"
@@ -40,7 +40,7 @@ static unsigned int pack_max_fds;
 static size_t peak_pack_mapped;
 static size_t pack_mapped;
 struct packed_git *packed_git;
-struct mru packed_git_mru = {{&packed_git_mru.list, &packed_git_mru.list}};
+LIST_HEAD(packed_git_mru);
 
 #define SZ_FMT PRIuMAX
 static inline uintmax_t sz_fmt(size_t s) { return s; }
@@ -859,9 +859,10 @@ static void prepare_packed_git_mru(void)
 {
 	struct packed_git *p;
 
-	mru_clear(&packed_git_mru);
+	INIT_LIST_HEAD(&packed_git_mru);
+
 	for (p = packed_git; p; p = p->next)
-		mru_append(&packed_git_mru, p);
+		list_add_tail(&p->mru, &packed_git_mru);
 }
 
 static int prepare_packed_git_run_once = 0;
@@ -1830,10 +1831,10 @@ int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 	if (!packed_git)
 		return 0;
 
-	list_for_each(pos, &packed_git_mru.list) {
-		struct mru *p = list_entry(pos, struct mru, list);
-		if (fill_pack_entry(sha1, e, p->item)) {
-			mru_mark(&packed_git_mru, p);
+	list_for_each(pos, &packed_git_mru) {
+		struct packed_git *p = list_entry(pos, struct packed_git, mru);
+		if (fill_pack_entry(sha1, e, p)) {
+			list_move(&p->mru, &packed_git_mru);
 			return 1;
 		}
 	}
diff --git a/sha1_file.c b/sha1_file.c
index 5a2014811f..e664f2d70d 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -24,7 +24,6 @@
 #include "bulk-checkin.h"
 #include "streaming.h"
 #include "dir.h"
-#include "mru.h"
 #include "list.h"
 #include "mergesort.h"
 #include "quote.h"