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From: =?UTF-8?q?Nguy=E1=BB=85n=20Th=C3=A1i=20Ng=E1=BB=8Dc=20Duy?= 
	<pclouds@gmail.com>
Subject: [PATCH 22/32] split-index: the reading part
Date: Mon, 28 Apr 2014 17:55:43 +0700
Message-ID: <1398682553-11634-23-git-send-email-pclouds@gmail.com>
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CE_REMOVE'd entries are removed here because only parts of the code
base (unpack_trees in fact) test this bit when they look for the
presence of an entry. Leaving them may confuse the code ignores this
bit and expects to see a real entry.

Signed-off-by: Nguy=E1=BB=85n Th=C3=A1i Ng=E1=BB=8Dc Duy <pclouds@gmail=
=2Ecom>
---
 read-cache.c  |  2 --
 split-index.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++=
++++++--
 split-index.h |  2 ++
 3 files changed, 84 insertions(+), 4 deletions(-)

diff --git a/read-cache.c b/read-cache.c
index a717171..a5517bf 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1569,8 +1569,6 @@ int read_index_from(struct index_state *istate, c=
onst char *path)
=20
 	if (is_null_sha1(split_index->base_sha1))
 		return ret;
-	if (istate->cache_nr)
-		die("index in split-index mode must contain no entries");
=20
 	if (split_index->base)
 		discard_index(split_index->base);
diff --git a/split-index.c b/split-index.c
index 5708807..b03a250 100644
--- a/split-index.c
+++ b/split-index.c
@@ -16,13 +16,27 @@ int read_link_extension(struct index_state *istate,
 {
 	const unsigned char *data =3D data_;
 	struct split_index *si;
+	int ret;
+
 	if (sz < 20)
 		return error("corrupt link extension (too short)");
 	si =3D init_split_index(istate);
 	hashcpy(si->base_sha1, data);
 	data +=3D 20;
 	sz -=3D 20;
-	if (sz)
+	if (!sz)
+		return 0;
+	si->delete_bitmap =3D ewah_new();
+	ret =3D ewah_read_mmap(si->delete_bitmap, data, sz);
+	if (ret < 0)
+		return error("corrupt delete bitmap in link extension");
+	data +=3D ret;
+	sz -=3D ret;
+	si->replace_bitmap =3D ewah_new();
+	ret =3D ewah_read_mmap(si->replace_bitmap, data, sz);
+	if (ret < 0)
+		return error("corrupt replace bitmap in link extension");
+	if (ret !=3D sz)
 		return error("garbage at the end of link extension");
 	return 0;
 }
@@ -60,15 +74,81 @@ static void mark_base_index_entries(struct index_st=
ate *base)
 		base->cache[i]->index =3D i + 1;
 }
=20
+static void mark_entry_for_delete(size_t pos, void *data)
+{
+	struct index_state *istate =3D data;
+	if (pos >=3D istate->cache_nr)
+		die("position for delete %d exceeds base index size %d",
+		    (int)pos, istate->cache_nr);
+	istate->cache[pos]->ce_flags |=3D CE_REMOVE;
+	istate->split_index->nr_deletions =3D 1;
+}
+
+static void replace_entry(size_t pos, void *data)
+{
+	struct index_state *istate =3D data;
+	struct split_index *si =3D istate->split_index;
+	struct cache_entry *dst, *src;
+	if (pos >=3D istate->cache_nr)
+		die("position for replacement %d exceeds base index size %d",
+		    (int)pos, istate->cache_nr);
+	if (si->nr_replacements >=3D si->saved_cache_nr)
+		die("too many replacements (%d vs %d)",
+		    si->nr_replacements, si->saved_cache_nr);
+	dst =3D istate->cache[pos];
+	if (dst->ce_flags & CE_REMOVE)
+		die("entry %d is marked as both replaced and deleted",
+		    (int)pos);
+	src =3D si->saved_cache[si->nr_replacements];
+	src->index =3D pos + 1;
+	src->ce_flags |=3D CE_UPDATE_IN_BASE;
+	free(dst);
+	dst =3D src;
+	si->nr_replacements++;
+}
+
 void merge_base_index(struct index_state *istate)
 {
 	struct split_index *si =3D istate->split_index;
+	unsigned int i;
=20
 	mark_base_index_entries(si->base);
-	istate->cache_nr =3D si->base->cache_nr;
+
+	si->saved_cache	    =3D istate->cache;
+	si->saved_cache_nr  =3D istate->cache_nr;
+	istate->cache_nr    =3D si->base->cache_nr;
+	istate->cache	    =3D NULL;
+	istate->cache_alloc =3D 0;
 	ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
 	memcpy(istate->cache, si->base->cache,
 	       sizeof(*istate->cache) * istate->cache_nr);
+
+	si->nr_deletions =3D 0;
+	si->nr_replacements =3D 0;
+	ewah_each_bit(si->replace_bitmap, replace_entry, istate);
+	ewah_each_bit(si->delete_bitmap, mark_entry_for_delete, istate);
+	if (si->nr_deletions)
+		remove_marked_cache_entries(istate);
+
+	for (i =3D si->nr_replacements; i < si->saved_cache_nr; i++) {
+		add_index_entry(istate, si->saved_cache[i],
+				ADD_CACHE_OK_TO_ADD |
+				/*
+				 * we may have to replay what
+				 * merge-recursive.c:update_stages()
+				 * does, which has this flag on
+				 */
+				ADD_CACHE_SKIP_DFCHECK);
+		si->saved_cache[i] =3D NULL;
+	}
+
+	ewah_free(si->delete_bitmap);
+	ewah_free(si->replace_bitmap);
+	free(si->saved_cache);
+	si->delete_bitmap  =3D NULL;
+	si->replace_bitmap =3D NULL;
+	si->saved_cache	   =3D NULL;
+	si->saved_cache_nr =3D 0;
 }
=20
 void prepare_to_write_split_index(struct index_state *istate)
diff --git a/split-index.h b/split-index.h
index 53b778f..c1324f5 100644
--- a/split-index.h
+++ b/split-index.h
@@ -12,6 +12,8 @@ struct split_index {
 	struct ewah_bitmap *replace_bitmap;
 	struct cache_entry **saved_cache;
 	unsigned int saved_cache_nr;
+	unsigned int nr_deletions;
+	unsigned int nr_replacements;
 	int refcount;
 };
=20
--=20
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