thodg/libgit2

diff --git a/include/git2/commit.h b/include/git2/commit.h
index c09b348..3687d94 100644
--- a/include/git2/commit.h
+++ b/include/git2/commit.h
@@ -136,6 +136,16 @@ GIT_EXTERN(const git_signature *) git_commit_author(git_commit *commit);
 GIT_EXTERN(int) git_commit_tree(git_tree **tree_out, git_commit *commit);
 
 /**
+ * Get the id of the tree pointed to by a commit. This differs from
+ * `git_commit_tree` in that no attempts are made to fetch an object
+ * from the ODB.
+ *
+ * @param commit a previously loaded commit.
+ * @return the id of tree pointed to by commit.
+ */
+GIT_EXTERN(const git_oid *) git_commit_tree_oid(git_commit *commit);
+
+/**
  * Get the number of parents of this commit
  *
  * @param commit a previously loaded commit.
@@ -153,6 +163,16 @@ GIT_EXTERN(unsigned int) git_commit_parentcount(git_commit *commit);
  */
 GIT_EXTERN(int) git_commit_parent(git_commit **parent, git_commit *commit, unsigned int n);
 
+/**
+ * Get the oid of a specified parent for a commit. This is different from
+ * `git_commit_parent`, which will attempt to load the parent commit from
+ * the ODB.
+ *
+ * @param commit a previously loaded commit.
+ * @param n the position of the parent (from 0 to `parentcount`)
+ * @return the id of the parent, NULL on error.
+ */
+GIT_EXTERN(const git_oid *) git_commit_parent_oid(git_commit *commit, unsigned int n);
 
 /**
  * Create a new commit in the repository
diff --git a/include/git2/common.h b/include/git2/common.h
index e0c6bc5..22c7cc4 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -164,6 +164,12 @@
 /** A reference with this name already exists */
 #define GIT_EEXISTS (GIT_ERROR - 23)
 
+/** The given integer literal is too large to be parsed */
+#define GIT_EOVERFLOW (GIT_ERROR - 24)
+
+/** The given literal is not a valid number */
+#define GIT_ENOTNUM (GIT_ERROR - 25)
+
 GIT_BEGIN_DECL
 
 typedef struct {
diff --git a/include/git2/repository.h b/include/git2/repository.h
index 00c1f20..c47fcfc 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -182,6 +182,36 @@ GIT_EXTERN(void) git_repository_free(git_repository *repo);
  */
 GIT_EXTERN(int) git_repository_init(git_repository **repo_out, const char *path, unsigned is_bare);
 
+/**
+ * Check if a repository is empty
+ *
+ * An empty repository has just been initialized and contains
+ * no commits.
+ *
+ * @param repo Repo to test
+ * @return 1 if the repository is empty, 0 if it isn't, error code
+ * if the repository is corrupted
+ */
+GIT_EXTERN(int) git_repository_is_empty(git_repository *repo);
+
+/**
+ * Get the normalized path to the git repository.
+ *
+ * @param repo a repository object
+ * @return absolute path to the git directory
+ */
+GIT_EXTERN(const char *) git_repository_path(git_repository *repo);
+
+/**
+ * Get the normalized path to the working directory of the repository.
+ *
+ * If the repository is bare, there is no working directory and NULL we be returned.
+ *
+ * @param repo a repository object
+ * @return NULL if the repository is bare; absolute path to the working directory otherwise.
+ */
+GIT_EXTERN(const char *) git_repository_workdir(git_repository *repo);
+
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/include/git2/signature.h b/include/git2/signature.h
index 40412a4..44d1f28 100644
--- a/include/git2/signature.h
+++ b/include/git2/signature.h
@@ -41,19 +41,30 @@ GIT_BEGIN_DECL
  * Create a new action signature. The signature must be freed
  * manually or using git_signature_free
  *
- * @name name of the person
- * @email email of the person
- * @time time when the action happened
- * @offset timezone offset in minutes for the time
+ * @param name name of the person
+ * @param mail email of the person
+ * @param time time when the action happened
+ * @param offset timezone offset in minutes for the time
  * @return the new sig, NULL on out of memory
  */
 GIT_EXTERN(git_signature *) git_signature_new(const char *name, const char *email, git_time_t time, int offset);
 
 /**
+ * Create a new action signature with a timestamp of 'now'. The
+ * signature must be freed manually or using git_signature_free
+ *
+ * @param name name of the person
+ * @param email email of the person
+ * @return the new sig, NULL on out of memory
+ */
+GIT_EXTERN(git_signature *) git_signature_now(const char *name, const char *email);
+
+
+/**
  * Create a copy of an existing signature.
  *
  * All internal strings are also duplicated.
- * @sig signature to duplicated
+ * @param sig signature to duplicated
  * @return a copy of sig, NULL on out of memory
  */
 GIT_EXTERN(git_signature *) git_signature_dup(const git_signature *sig);
@@ -61,7 +72,7 @@ GIT_EXTERN(git_signature *) git_signature_dup(const git_signature *sig);
 /**
  * Free an existing signature
  *
- * @sig signature to free
+ * @param sig signature to free
  */
 GIT_EXTERN(void) git_signature_free(git_signature *sig);
 
diff --git a/src/backends/hiredis.c b/src/backends/hiredis.c
new file mode 100644
index 0000000..707412b
--- /dev/null
+++ b/src/backends/hiredis.c
@@ -0,0 +1,200 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * In addition to the permissions in the GNU General Public License,
+ * the authors give you unlimited permission to link the compiled
+ * version of this file into combinations with other programs,
+ * and to distribute those combinations without any restriction
+ * coming from the use of this file.  (The General Public License
+ * restrictions do apply in other respects; for example, they cover
+ * modification of the file, and distribution when not linked into
+ * a combined executable.)
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "common.h"
+#include "git2/object.h"
+#include "hash.h"
+#include "odb.h"
+
+#include "git2/odb_backend.h"
+
+#ifdef GIT2_HIREDIS_BACKEND
+
+#include <hiredis/hiredis.h>
+
+typedef struct {
+    git_odb_backend parent;
+
+    redisContext *db;
+} hiredis_backend;
+
+int hiredis_backend__read_header(size_t *len_p, git_otype *type_p, git_odb_backend *_backend, const git_oid *oid) {
+    hiredis_backend *backend;
+    int error;
+    redisReply *reply;
+
+    assert(len_p && type_p && _backend && oid);
+
+    backend = (hiredis_backend *) _backend;
+    error = GIT_ERROR;
+
+    reply = redisCommand(backend->db, "HMGET %b %s %s", oid->id, GIT_OID_RAWSZ,
+            "type", "size");
+
+    if (reply->type == REDIS_REPLY_ARRAY) {
+        if (reply->element[0]->type != REDIS_REPLY_NIL &&
+                reply->element[0]->type != REDIS_REPLY_NIL) {
+            *type_p = (git_otype) atoi(reply->element[0]->str);
+            *len_p = (size_t) atoi(reply->element[1]->str);
+            error = GIT_SUCCESS;
+        } else {
+            error = GIT_ENOTFOUND;
+        }
+    } else {
+        error = GIT_ERROR;
+    }
+
+    freeReplyObject(reply);
+    return error;
+}
+
+int hiredis_backend__read(void **data_p, size_t *len_p, git_otype *type_p, git_odb_backend *_backend, const git_oid *oid) {
+    hiredis_backend *backend;
+    int error;
+    redisReply *reply;
+
+    assert(data_p && len_p && type_p && _backend && oid);
+
+    backend = (hiredis_backend *) _backend;
+    error = GIT_ERROR;
+
+    reply = redisCommand(backend->db, "HMGET %b %s %s %s", oid->id, GIT_OID_RAWSZ,
+            "type", "size", "data");
+
+    if (reply->type == REDIS_REPLY_ARRAY) {
+        if (reply->element[0]->type != REDIS_REPLY_NIL &&
+                reply->element[1]->type != REDIS_REPLY_NIL &&
+                reply->element[2]->type != REDIS_REPLY_NIL) {
+            *type_p = (git_otype) atoi(reply->element[0]->str);
+            *len_p = (size_t) atoi(reply->element[1]->str);
+            *data_p = git__malloc(*len_p);
+            if (*data_p == NULL) {
+                error = GIT_ENOMEM;
+            } else {
+                memcpy(*data_p, reply->element[2]->str, *len_p);
+                error = GIT_SUCCESS;
+            }
+        } else {
+            error = GIT_ENOTFOUND;
+        }
+    } else {
+        error = GIT_ERROR;
+    }
+
+    freeReplyObject(reply);
+    return error;
+}
+
+int hiredis_backend__exists(git_odb_backend *_backend, const git_oid *oid) {
+    hiredis_backend *backend;
+    int found;
+    redisReply *reply;
+
+    assert(_backend && oid);
+
+    backend = (hiredis_backend *) _backend;
+    found = 0;
+
+    reply = redisCommand(backend->db, "exists %b", oid->id, GIT_OID_RAWSZ);
+    if (reply->type != REDIS_REPLY_NIL && reply->type != REDIS_REPLY_ERROR)
+        found = 1;
+
+
+    freeReplyObject(reply);
+    return found;
+}
+
+int hiredis_backend__write(git_oid *id, git_odb_backend *_backend, const void *data, size_t len, git_otype type) {
+    hiredis_backend *backend;
+    int error;
+    redisReply *reply;
+
+    assert(id && _backend && data);
+
+    backend = (hiredis_backend *) _backend;
+    error = GIT_ERROR;
+
+    if ((error = git_odb_hash(id, data, len, type)) < 0)
+        return error;
+
+    reply = redisCommand(backend->db, "HMSET %b "
+            "type %d "
+            "size %d "
+            "data %b ", id->id, GIT_OID_RAWSZ,
+            (int) type, len, data, len);
+    error = reply->type == REDIS_REPLY_ERROR ? GIT_ERROR : GIT_SUCCESS;
+
+    freeReplyObject(reply);
+    return error;
+}
+
+void hiredis_backend__free(git_odb_backend *_backend) {
+    hiredis_backend *backend;
+    assert(_backend);
+    backend = (hiredis_backend *) _backend;
+
+    redisFree(backend->db);
+
+    free(backend);
+}
+
+int git_odb_backend_hiredis(git_odb_backend **backend_out, const char *host, int port) {
+    hiredis_backend *backend;
+
+    backend = git__calloc(1, sizeof (hiredis_backend));
+    if (backend == NULL)
+        return GIT_ENOMEM;
+
+
+    backend->db = redisConnect(host, port);
+    if (backend->db->err)
+        goto cleanup;
+
+    backend->parent.read = &hiredis_backend__read;
+    backend->parent.read_header = &hiredis_backend__read_header;
+    backend->parent.write = &hiredis_backend__write;
+    backend->parent.exists = &hiredis_backend__exists;
+    backend->parent.free = &hiredis_backend__free;
+
+    *backend_out = (git_odb_backend *) backend;
+
+    return GIT_SUCCESS;
+cleanup:
+    free(backend);
+    return GIT_ERROR;
+}
+
+#else
+
+int git_odb_backend_hiredis(git_odb_backend ** GIT_UNUSED(backend_out),
+        const char *GIT_UNUSED(host), int GIT_UNUSED(port)) {
+    GIT_UNUSED_ARG(backend_out);
+    GIT_UNUSED_ARG(host);
+    GIT_UNUSED_ARG(port);
+    return GIT_ENOTIMPLEMENTED;
+}
+
+
+#endif /* HAVE_HIREDIS */
diff --git a/src/commit.c b/src/commit.c
index 9fc3f07..9621703 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -318,6 +318,7 @@ GIT_COMMIT_GETTER(const char *, message_short, commit->message_short)
 GIT_COMMIT_GETTER(git_time_t, time, commit->committer->when.time)
 GIT_COMMIT_GETTER(int, time_offset, commit->committer->when.offset)
 GIT_COMMIT_GETTER(unsigned int, parentcount, commit->parent_oids.length)
+GIT_COMMIT_GETTER(const git_oid *, tree_oid, &commit->tree_oid);
 
 
 int git_commit_tree(git_tree **tree_out, git_commit *commit)
@@ -338,4 +339,9 @@ int git_commit_parent(git_commit **parent, git_commit *commit, unsigned int n)
 	return git_commit_lookup(parent, commit->object.repo, parent_oid);
 }
 
+const git_oid *git_commit_parent_oid(git_commit *commit, unsigned int n)
+{
+	assert(commit);
 
+	return git_vector_get(&commit->parent_oids, n);
+}
diff --git a/src/errors.c b/src/errors.c
index 3c0e8eb..c3a495c 100644
--- a/src/errors.c
+++ b/src/errors.c
@@ -29,7 +29,9 @@ static struct {
 	{GIT_EREVWALKOVER, "The revision walker is empty; there are no more commits left to iterate"},
 	{GIT_EINVALIDREFSTATE, "The state of the reference is not valid"},
 	{GIT_ENOTIMPLEMENTED, "This feature has not been implemented yet"},
-	{GIT_EEXISTS, "A reference with this name already exists"}
+	{GIT_EEXISTS, "A reference with this name already exists"},
+	{GIT_EOVERFLOW, "The given integer literal is too large to be parsed"},
+	{GIT_ENOTNUM, "The given literal is not a valid number"},
 };
 
 const char *git_strerror(int num)
diff --git a/src/filebuf.c b/src/filebuf.c
index dff9373..eb93424 100644
--- a/src/filebuf.c
+++ b/src/filebuf.c
@@ -178,7 +178,7 @@ int git_filebuf_open(git_filebuf *file, const char *path, int flags)
 	if (flags & GIT_FILEBUF_DEFLATE_CONTENTS) {
 
 		/* Initialize the ZLib stream */
-		if (deflateInit(&file->zs, Z_DEFAULT_COMPRESSION) != Z_OK) {
+		if (deflateInit(&file->zs, Z_BEST_SPEED) != Z_OK) {
 			error = GIT_EZLIB;
 			goto cleanup;
 		}
diff --git a/src/index.c b/src/index.c
index 6a67e9c..fdf14c3 100644
--- a/src/index.c
+++ b/src/index.c
@@ -412,6 +412,7 @@ static git_index_tree *read_tree_internal(
 {
 	git_index_tree *tree;
 	const char *name_start, *buffer;
+	long count;
 
 	if ((tree = git__malloc(sizeof(git_index_tree))) == NULL)
 		return NULL;
@@ -430,12 +431,22 @@ static git_index_tree *read_tree_internal(
 		goto error_cleanup;
 
 	/* Blank-terminated ASCII decimal number of entries in this tree */
-	tree->entries = strtol(buffer, (char **)&buffer, 10);
+	if (git__strtol32(&count, buffer, &buffer, 10) < GIT_SUCCESS ||
+		count < 0)
+		goto error_cleanup;
+
+	tree->entries = (size_t)count;
+
 	if (*buffer != ' ' || ++buffer >= buffer_end)
 		goto error_cleanup;
 
 	 /* Number of children of the tree, newline-terminated */
-	tree->children_count = strtol(buffer, (char **)&buffer, 10);
+	if (git__strtol32(&count, buffer, &buffer, 10) < GIT_SUCCESS ||
+		count < 0)
+		goto error_cleanup;
+
+	tree->children_count = (size_t)count;
+
 	if (*buffer != '\n' || ++buffer >= buffer_end)
 		goto error_cleanup;
 
diff --git a/src/refs.c b/src/refs.c
index 9661988..00b9ff6 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -746,7 +746,7 @@ static int packed_write_ref(reference_oid *ref, git_filebuf *file)
  */
 static int packed_find_peel(reference_oid *ref)
 {
-	git_tag *tag;
+	git_object *object;
 	int error;
 
 	if (ref->ref.type & GIT_REF_HAS_PEEL)
@@ -760,25 +760,32 @@ static int packed_find_peel(reference_oid *ref)
 		return GIT_SUCCESS;
 
 	/*
-	 * Find the tag in the repository. The tag must exist,
-	 * otherwise this reference is broken and we shouldn't
-	 * pack it.
+	 * Find the tagged object in the repository
 	 */
-	error = git_tag_lookup(&tag, ref->ref.owner, &ref->oid);
+	error = git_object_lookup(&object, ref->ref.owner, &ref->oid, GIT_OBJ_ANY);
 	if (error < GIT_SUCCESS)
 		return GIT_EOBJCORRUPTED;
 
 	/*
-	 * Find the object pointed at by this tag
+	 * If the tagged object is a Tag object, we need to resolve it;
+	 * if the ref is actually a 'weak' ref, we don't need to resolve
+	 * anything.
 	 */
-	git_oid_cpy(&ref->peel_target, git_tag_target_oid(tag));
-	ref->ref.type |= GIT_REF_HAS_PEEL;
+	if (git_object_type(object) == GIT_OBJ_TAG) {
+		git_tag *tag = (git_tag *)object;
 
-	/* 
-	 * The reference has now cached the resolved OID, and is
-	 * marked at such. When written to the packfile, it'll be
-	 * accompanied by this resolved oid
-	 */
+		/*
+		 * Find the object pointed at by this tag
+		 */
+		git_oid_cpy(&ref->peel_target, git_tag_target_oid(tag));
+		ref->ref.type |= GIT_REF_HAS_PEEL;
+
+		/*
+		 * The reference has now cached the resolved OID, and is
+		 * marked at such. When written to the packfile, it'll be
+		 * accompanied by this resolved oid
+		 */
+	}
 
 	return GIT_SUCCESS;
 }
@@ -1419,6 +1426,10 @@ int git_reference_delete(git_reference *ref)
 	assert(ref);
 
 	if (ref->type & GIT_REF_PACKED) {
+		/* load the existing packfile */
+		if ((error = packed_load(ref->owner)) < GIT_SUCCESS)
+			return error;
+		
 		git_hashtable_remove(ref->owner->references.packfile, ref->name);
 		error = packed_write(ref->owner);
 	} else {
diff --git a/src/repository.c b/src/repository.c
index abbbd12..c428b00 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -473,3 +473,29 @@ cleanup:
 	return error;
 }
 
+int git_repository_is_empty(git_repository *repo)
+{
+	git_reference *head, *branch;
+	int error;
+
+	error = git_reference_lookup(&head, repo, "HEAD");
+	if (error < GIT_SUCCESS)
+		return error;
+
+	if (git_reference_type(head) != GIT_REF_SYMBOLIC)
+		return GIT_EOBJCORRUPTED;
+
+	return git_reference_resolve(&branch, head) == GIT_SUCCESS ? 0 : 1;
+}
+
+const char *git_repository_path(git_repository *repo)
+{
+	assert(repo);
+	return repo->path_repository;
+}
+
+const char *git_repository_workdir(git_repository *repo)
+{
+	assert(repo);
+	return repo->path_workdir;
+}
diff --git a/src/revwalk.c b/src/revwalk.c
index 73bb060..b62b099 100644
--- a/src/revwalk.c
+++ b/src/revwalk.c
@@ -191,6 +191,7 @@ static int commit_quick_parse(git_revwalk *walk, commit_object *commit, git_rawo
 	unsigned char *parents_start;
 
 	int i, parents = 0;
+	long commit_time;
 
 	buffer += STRLEN("tree ") + GIT_OID_HEXSZ + 1;
 
@@ -227,10 +228,10 @@ static int commit_quick_parse(git_revwalk *walk, commit_object *commit, git_rawo
 	if (buffer == NULL)
 		return GIT_EOBJCORRUPTED;
 
-	commit->time = strtol((char *)buffer + 2, NULL, 10);
-	if (commit->time == 0)
+	if (git__strtol32(&commit_time, (char *)buffer + 2, NULL, 10) < GIT_SUCCESS)
 		return GIT_EOBJCORRUPTED;
 
+	commit->time = (time_t)commit_time;
 	commit->parsed = 1;
 	return GIT_SUCCESS;
 }
diff --git a/src/signature.c b/src/signature.c
index 0c99755..e801462 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -65,14 +65,47 @@ git_signature *git_signature_dup(const git_signature *sig)
 	return git_signature_new(sig->name, sig->email, sig->when.time, sig->when.offset);
 }
 
+git_signature *git_signature_now(const char *name, const char *email)
+{
+	time_t now;
+	time_t offset;
+	struct tm *utc_tm, *local_tm;
+
+#ifndef GIT_WIN32
+	struct tm _utc, _local;
+#endif
+
+	time(&now);
+
+	/**
+	 * On Win32, `gmtime_r` doesn't exist but
+	 * `gmtime` is threadsafe, so we can use that
+	 */
+#ifdef GIT_WIN32
+	utc_tm = gmtime(&now);
+	local_tm = localtime(&now);
+#else
+	utc_tm = gmtime_r(&now, &_utc);
+	local_tm = localtime_r(&now, &_local);
+#endif
+
+	offset = mktime(local_tm) - mktime(utc_tm);
+	offset /= 60;
+
+	/* mktime takes care of setting tm_isdst correctly */
+	if (local_tm->tm_isdst)
+		offset += 60;
+
+	return git_signature_new(name, email, now, (int)offset);
+}
 
-static int parse_timezone_offset(const char *buffer, int *offset_out)
+static int parse_timezone_offset(const char *buffer, long *offset_out)
 {
-	int offset, dec_offset;
+	long offset, dec_offset;
 	int mins, hours;
 
-	const char* offset_start;
-	char* offset_end;
+	const char *offset_start;
+	const char *offset_end;
 
 	offset_start = buffer + 1;
 
@@ -84,7 +117,8 @@ static int parse_timezone_offset(const char *buffer, int *offset_out)
 	if (offset_start[0] != '-' && offset_start[0] != '+')
 		return GIT_EOBJCORRUPTED;
 
-	dec_offset = strtol(offset_start + 1, &offset_end, 10);
+	if (git__strtol32(&dec_offset, offset_start + 1, &offset_end, 10) < GIT_SUCCESS)
+		return GIT_EOBJCORRUPTED;
 
 	if (offset_end - offset_start != 5)
 		return GIT_EOBJCORRUPTED;
@@ -117,7 +151,7 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 	int name_length, email_length;
 	const char *buffer = *buffer_out;
 	const char *line_end, *name_end, *email_end;
-	int offset = 0;
+	long offset = 0, time;
 
 	memset(sig, 0x0, sizeof(git_signature));
 
@@ -139,6 +173,9 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 
 	name_length = name_end - buffer - 1;
 	sig->name = git__malloc(name_length + 1);
+	if (sig->name == NULL)
+		return GIT_ENOMEM;
+
 	memcpy(sig->name, buffer, name_length);
 	sig->name[name_length] = 0;
 	buffer = name_end + 1;
@@ -152,6 +189,9 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 
 	email_length = email_end - buffer;
 	sig->email = git__malloc(email_length + 1);
+	if (sig->name == NULL)
+		return GIT_ENOMEM;
+
 	memcpy(sig->email, buffer, email_length);
 	sig->email[email_length] = 0;
 	buffer = email_end + 1;
@@ -159,11 +199,11 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 	if (buffer >= line_end)
 		return GIT_EOBJCORRUPTED;
 
-	sig->when.time = strtol(buffer, (char **)&buffer, 10);
-
-	if (sig->when.time == 0)
+	if (git__strtol32(&time, buffer, &buffer, 10) < GIT_SUCCESS)
 		return GIT_EOBJCORRUPTED;
 
+	sig->when.time = (time_t)time;
+
 	if (parse_timezone_offset(buffer, &offset) < GIT_SUCCESS)
 		return GIT_EOBJCORRUPTED;
 	
diff --git a/src/tag.c b/src/tag.c
index ef58e09..a340095 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -131,12 +131,17 @@ static int parse_tag_buffer(git_tag *tag, const char *buffer, const char *buffer
 	text_len = search - buffer;
 
 	tag->tag_name = git__malloc(text_len + 1);
+	if (tag->tag_name == NULL)
+		return GIT_ENOMEM;
+
 	memcpy(tag->tag_name, buffer, text_len);
 	tag->tag_name[text_len] = '\0';
 
 	buffer = search + 1;
 
 	tag->tagger = git__malloc(sizeof(git_signature));
+	if (tag->tagger == NULL)
+		return GIT_ENOMEM;
 
 	if ((error = git_signature__parse(tag->tagger, &buffer, buffer_end, "tagger ")) != 0) {
 		free(tag->tag_name);
@@ -147,6 +152,9 @@ static int parse_tag_buffer(git_tag *tag, const char *buffer, const char *buffer
 	text_len = buffer_end - ++buffer;
 
 	tag->message = git__malloc(text_len + 1);
+	if (tag->message == NULL)
+		return GIT_ENOMEM;
+
 	memcpy(tag->message, buffer, text_len);
 	tag->message[text_len] = '\0';
 
@@ -209,6 +217,17 @@ static int tag_create(
 		return error;
 	}
 
+	if (!git_odb_exists(repo->db, target))
+		return GIT_ENOTFOUND;
+
+	/* Try to find out what the type is */
+	if (target_type == GIT_OBJ_ANY) {
+		size_t _unused;
+		error = git_odb_read_header(&_unused, &target_type, repo->db, target);
+		if (error < GIT_SUCCESS)
+			return error;
+	}
+
 	type_str = git_object_type2string(target_type);
 
 	tagger_str_len = git_signature__write(&tagger_str, "tagger", tagger);
@@ -260,7 +279,6 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 {
 	git_tag tag;
 	int error;
-	git_object *obj;
 
 	assert(oid && buffer);
 
@@ -269,15 +287,8 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 	if ((error = parse_tag_buffer(&tag, buffer, buffer + strlen(buffer))) < GIT_SUCCESS)
 		return error;
 
-	error = git_object_lookup(&obj, repo, &tag.target, tag.type);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	error = git_tag_create_o(oid, repo, tag.tag_name, obj, tag.tagger, tag.message);
-
-	git_object_close(obj);
+	error = git_tag_create(oid, repo, tag.tag_name, &tag.target, tag.type, tag.tagger, tag.message);
 
-cleanup:
 	git_signature_free(tag.tagger);
 	free(tag.tag_name);
 	free(tag.message);
diff --git a/src/tree.c b/src/tree.c
index 693ed1c..64f81d7 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -150,7 +150,8 @@ static int tree_parse_buffer(git_tree *tree, const char *buffer, const char *buf
 		if (git_vector_insert(&tree->entries, entry) < GIT_SUCCESS)
 			return GIT_ENOMEM;
 
-		entry->attr = strtol(buffer, (char **)&buffer, 8);
+		if (git__strtol32((long *)&entry->attr, buffer, &buffer, 8) < GIT_SUCCESS)
+			return GIT_EOBJCORRUPTED;
 
 		if (*buffer++ != ' ') {
 			error = GIT_EOBJCORRUPTED;
@@ -364,7 +365,7 @@ int git_treebuilder_insert(git_tree_entry **entry_out, git_treebuilder *bld, con
 	git_oid_cpy(&entry->oid, id);
 	entry->attr = attributes;
 
-	if (pos != GIT_ENOTFOUND) {
+	if (pos == GIT_ENOTFOUND) {
 		if (git_vector_insert(&bld->entries, entry) < 0)
 			return GIT_ENOMEM;
 	}
diff --git a/src/util.c b/src/util.c
index 995daf3..55a7ab2 100644
--- a/src/util.c
+++ b/src/util.c
@@ -2,6 +2,7 @@
 #include "common.h"
 #include <stdarg.h>
 #include <stdio.h>
+#include <ctype.h>
 
 void git_strarray_free(git_strarray *array)
 {
@@ -12,6 +13,84 @@ void git_strarray_free(git_strarray *array)
 	free(array->strings);
 }
 
+int git__strtol32(long *result, const char *nptr, const char **endptr, int base)
+{
+	const char *p;
+	long n, nn;
+	int c, ovfl, v, neg, ndig;
+
+	p = nptr;
+	neg = 0;
+	n = 0;
+	ndig = 0;
+	ovfl = 0;
+
+	/*
+	 * White space
+	 */
+	while (isspace(*p))
+		p++;
+
+	/*
+	 * Sign
+	 */
+	if (*p == '-' || *p == '+')
+		if (*p++ == '-')
+			neg = 1;
+
+	/*
+	 * Base
+	 */
+	if (base == 0) {
+		if (*p != '0')
+			base = 10;
+		else {
+			base = 8;
+			if (p[1] == 'x' || p[1] == 'X') {
+				p += 2;
+				base = 16;
+			}
+		}
+	} else if (base == 16 && *p == '0') {
+		if (p[1] == 'x' || p[1] == 'X')
+			p += 2;
+	} else if (base < 0 || 36 < base)
+		goto Return;
+
+	/*
+	 * Non-empty sequence of digits
+	 */
+	for (;; p++,ndig++) {
+		c = *p;
+		v = base;
+		if ('0'<=c && c<='9')
+			v = c - '0';
+		else if ('a'<=c && c<='z')
+			v = c - 'a' + 10;
+		else if ('A'<=c && c<='Z')
+			v = c - 'A' + 10;
+		if (v >= base)
+			break;
+		nn = n*base + v;
+		if (nn < n)
+			ovfl = 1;
+		n = nn;
+	}
+
+Return:
+	if (ndig == 0)
+		return GIT_ENOTNUM;
+
+	if (endptr)
+		*endptr = p;
+
+	if (ovfl)
+		return GIT_EOVERFLOW;
+
+	*result = neg ? -n : n;
+	return GIT_SUCCESS;
+}
+
 int git__fmt(char *buf, size_t buf_sz, const char *fmt, ...)
 {
 	va_list va;
diff --git a/src/util.h b/src/util.h
index f477b64..3c60649 100644
--- a/src/util.h
+++ b/src/util.h
@@ -22,6 +22,8 @@ extern int git__fmt(char *, size_t, const char *, ...)
 extern int git__prefixcmp(const char *str, const char *prefix);
 extern int git__suffixcmp(const char *str, const char *suffix);
 
+extern int git__strtol32(long *n, const char *buff, const char **end_buf, int base);
+
 /*
  * The dirname() function shall take a pointer to a character string
  * that contains a pathname, and return a pointer to a string that is a
diff --git a/tests/resources/testrepo.git/objects/f6/0079018b664e4e79329a7ef9559c8d9e0378d1 b/tests/resources/testrepo.git/objects/f6/0079018b664e4e79329a7ef9559c8d9e0378d1
index 0377096..697c94c 100644
Binary files a/tests/resources/testrepo.git/objects/f6/0079018b664e4e79329a7ef9559c8d9e0378d1 and b/tests/resources/testrepo.git/objects/f6/0079018b664e4e79329a7ef9559c8d9e0378d1 differ
diff --git a/tests/resources/testrepo.git/refs/tags/point_to_blob b/tests/resources/testrepo.git/refs/tags/point_to_blob
new file mode 100644
index 0000000..f874a3f
--- /dev/null
+++ b/tests/resources/testrepo.git/refs/tags/point_to_blob
@@ -0,0 +1 @@
+1385f264afb75a56a5bec74243be9b367ba4ca08
diff --git a/tests/t00-core.c b/tests/t00-core.c
index 4cb1114..ab9a683 100644
--- a/tests/t00-core.c
+++ b/tests/t00-core.c
@@ -233,7 +233,7 @@ BEGIN_TEST(path3, "prettify and validate a path to a file")
 	must_fail(ensure_file_path_normalized("d1/s1///s2/..//../s3/", NULL, 0));
 	must_pass(ensure_file_path_normalized("d1/s1//../s2/../../d2", "d2", CWD_AS_PREFIX | PATH_AS_SUFFIX));
 	must_fail(ensure_file_path_normalized("dir/sub/../", NULL, 0));
-	must_pass(ensure_file_path_normalized("../../a/../../b/c/d/../../e", "b/e", PATH_AS_SUFFIX));
+	must_pass(ensure_file_path_normalized("../a/../b/c/d/../../e", "b/e", PATH_AS_SUFFIX));
 	must_fail(ensure_file_path_normalized("....", NULL, 0));
 	must_fail(ensure_file_path_normalized("...", NULL, 0));
 	must_fail(ensure_file_path_normalized("./...", NULL, 0));
@@ -309,7 +309,7 @@ BEGIN_TEST(path4, "validate and prettify a path to a folder")
 	must_pass(ensure_dir_path_normalized("d1/s1///s2/..//../s3/", "d1/s3/", CWD_AS_PREFIX | PATH_AS_SUFFIX));
 	must_pass(ensure_dir_path_normalized("d1/s1//../s2/../../d2", "d2/", CWD_AS_PREFIX | PATH_AS_SUFFIX));
 	must_pass(ensure_dir_path_normalized("dir/sub/../", "dir/", CWD_AS_PREFIX | PATH_AS_SUFFIX));
-	must_pass(ensure_dir_path_normalized("../../a/../../b/c/d/../../e", "b/e/", PATH_AS_SUFFIX));
+	must_pass(ensure_dir_path_normalized("../a/../b/c/d/../../e", "b/e/", PATH_AS_SUFFIX));
 	must_fail(ensure_dir_path_normalized("....", NULL, 0));
 	must_fail(ensure_dir_path_normalized("...", NULL, 0));
 	must_fail(ensure_dir_path_normalized("./...", NULL, 0));
diff --git a/tests/t08-tag.c b/tests/t08-tag.c
index e701648..de67fdd 100644
--- a/tests/t08-tag.c
+++ b/tests/t08-tag.c
@@ -119,13 +119,10 @@ BEGIN_TEST(write0, "write a tag to the repository and read it again")
 
 END_TEST
 
-BEGIN_TEST(write1, "write a tag to the repository which points to an unknown oid and read it again")
+BEGIN_TEST(write1, "write a tag to the repository which points to an unknown oid should fail")
 	git_repository *repo;
-	git_tag *tag;
 	git_oid target_id, tag_id;
 	const git_signature *tagger;
-	git_reference *ref_tag;
-	git_object *zombie;
 
 	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
 
@@ -135,7 +132,7 @@ BEGIN_TEST(write1, "write a tag to the repository which points to an unknown oid
 	tagger = git_signature_new(TAGGER_NAME, TAGGER_EMAIL, 123456789, 60);
 	must_be_true(tagger != NULL);
 
-	must_pass(git_tag_create(
+	must_fail(git_tag_create(
 		&tag_id, /* out id */
 		repo,
 		"the-zombie-tag",
@@ -146,17 +143,6 @@ BEGIN_TEST(write1, "write a tag to the repository which points to an unknown oid
 
 	git_signature_free((git_signature *)tagger);
 
-	must_pass(git_tag_lookup(&tag, repo, &tag_id));
-	
-	/* The non existent target can not be looked up */
-	must_fail(git_tag_target(&zombie, tag));
-
-	must_pass(git_reference_lookup(&ref_tag, repo, "refs/tags/the-zombie-tag"));
-	
-	must_pass(git_reference_delete(ref_tag));
-	must_pass(remove_loose_object(REPOSITORY_FOLDER, (git_object *)tag));
-
-	git_tag_close(tag);
 	git_repository_free(repo);
 
 END_TEST
diff --git a/tests/t09-tree.c b/tests/t09-tree.c
index e4252db..bd88642 100644
--- a/tests/t09-tree.c
+++ b/tests/t09-tree.c
@@ -29,6 +29,10 @@
 
 static const char *tree_oid = "1810dff58d8a660512d4832e740f692884338ccd";
 
+static const char *blob_oid = "fa49b077972391ad58037050f2a75f74e3671e92";
+static const char *first_tree  = "181037049a54a1eb5fab404658a3a250b44335d7";
+static const char *second_tree = "f60079018b664e4e79329a7ef9559c8d9e0378d1";
+
 #if 0
 static int print_tree(git_repository *repo, const git_oid *tree_oid, int depth)
 {
@@ -126,11 +130,33 @@ BEGIN_TEST(write0, "write a tree from an index")
 END_TEST
 #endif
 
+BEGIN_TEST(write2, "write a tree from a memory")
+	git_repository *repo;
+	git_treebuilder *builder;
+	git_tree *tree;
+	git_oid id, bid, rid, id2;
+
+	must_pass(open_temp_repo(&repo, REPOSITORY_FOLDER));
+	git_oid_mkstr(&id, first_tree);
+	git_oid_mkstr(&id2, second_tree);
+	git_oid_mkstr(&bid, blob_oid);
+
+	//create a second tree from first tree using `git_treebuilder_insert` on REPOSITORY_FOLDER.
+	must_pass(git_tree_lookup(&tree, repo, &id));
+	must_pass(git_treebuilder_create(&builder, tree));
+	must_pass(git_treebuilder_insert(NULL,builder,"new.txt",&bid,0100644));
+	must_pass(git_treebuilder_write(&rid,repo,builder));
+
+	must_be_true(git_oid_cmp(&rid, &id2) == 0);
+	close_temp_repo(repo);
+END_TEST
+
 BEGIN_SUITE(tree)
 	//ADD_TEST(print0);
 	ADD_TEST(read0);
 	ADD_TEST(read1);
 	//ADD_TEST(write0);
 	//ADD_TEST(write1);
+	ADD_TEST(write2);
 END_SUITE
 
diff --git a/tests/t10-refs.c b/tests/t10-refs.c
index 2797cd8..a6a5601 100644
--- a/tests/t10-refs.c
+++ b/tests/t10-refs.c
@@ -456,6 +456,11 @@ BEGIN_TEST(pack1, "create a packfile from all the loose rn a repo")
 	must_be_true((reference->type & GIT_REF_PACKED) == 0);
 	must_be_true(strcmp(reference->name, loose_tag_ref_name) == 0);
 	
+	/*
+	 * We are now trying to pack also a loose reference
+	 * called `points_to_blob`, to make sure we can properly
+	 * pack weak tags
+	 */
 	must_pass(git_reference_packall(repo));
 
 	/* Ensure the packed-refs file exists */
@@ -877,10 +882,10 @@ BEGIN_TEST(list0, "try to list all the references in our test repo")
 			printf("# %s\n", ref_list.strings[i]);
 	}*/
 
-	/* We have exactly 7 refs in total if we include the packed ones:
+	/* We have exactly 8 refs in total if we include the packed ones:
 	 * there is a reference that exists both in the packfile and as
 	 * loose, but we only list it once */
-	must_be_true(ref_list.count == 7); 
+	must_be_true(ref_list.count == 8); 
 
 	git_strarray_free(&ref_list);
 	git_repository_free(repo);
diff --git a/tests/t12-repo.c b/tests/t12-repo.c
index adf20cf..70dba42 100644
--- a/tests/t12-repo.c
+++ b/tests/t12-repo.c
@@ -194,6 +194,8 @@ BEGIN_TEST(open0, "Open a bare repository that has just been initialized by git"
 	must_pass(remove_placeholders(TEMP_REPO_FOLDER, "dummy-marker.txt"));
 
 	must_pass(git_repository_open(&repo, TEMP_REPO_FOLDER));
+	must_be_true(git_repository_path(repo) != NULL);
+	must_be_true(git_repository_workdir(repo) == NULL);
 
 	git_repository_free(repo);
 	must_pass(rmdir_recurs(TEMP_REPO_FOLDER));
@@ -211,6 +213,8 @@ BEGIN_TEST(open1, "Open a standard repository that has just been initialized by 
 	must_pass(remove_placeholders(DEST_REPOSITORY_FOLDER, "dummy-marker.txt"));
 
 	must_pass(git_repository_open(&repo, DEST_REPOSITORY_FOLDER));
+	must_be_true(git_repository_path(repo) != NULL);
+	must_be_true(git_repository_workdir(repo) != NULL);
 
 	git_repository_free(repo);
 	must_pass(rmdir_recurs(TEMP_REPO_FOLDER));
@@ -244,6 +248,19 @@ BEGIN_TEST(open2, "Open a bare repository with a relative path escaping out of t
 	rmdir_recurs(TEMP_REPO_FOLDER);
 END_TEST
 
+BEGIN_TEST(empty0, "test if a repository is empty or not")
+
+	git_repository *repo_empty, *repo_normal;
+
+	must_pass(git_repository_open(&repo_normal, REPOSITORY_FOLDER));
+	must_be_true(git_repository_is_empty(repo_normal) == 0);
+	git_repository_free(repo_normal);
+
+	must_pass(git_repository_open(&repo_empty, EMPTY_BARE_REPOSITORY_FOLDER));
+	must_be_true(git_repository_is_empty(repo_empty) == 1);
+	git_repository_free(repo_empty);
+END_TEST
+
 BEGIN_SUITE(repository)
 	ADD_TEST(odb0);
 	ADD_TEST(odb1);
@@ -253,5 +270,6 @@ BEGIN_SUITE(repository)
 	ADD_TEST(open0);
 	ADD_TEST(open1);
 	ADD_TEST(open2);
+	ADD_TEST(empty0);
 END_SUITE
 
diff --git a/tests/t14-hiredis.c b/tests/t14-hiredis.c
new file mode 100644
index 0000000..c743f7d
--- /dev/null
+++ b/tests/t14-hiredis.c
@@ -0,0 +1,123 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * In addition to the permissions in the GNU General Public License,
+ * the authors give you unlimited permission to link the compiled
+ * version of this file into combinations with other programs,
+ * and to distribute those combinations without any restriction
+ * coming from the use of this file.  (The General Public License
+ * restrictions do apply in other respects; for example, they cover
+ * modification of the file, and distribution when not linked into
+ * a combined executable.)
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+#include "test_lib.h"
+#include "odb.h"
+
+#ifdef GIT2_HIREDIS_BACKEND
+#include "t03-data.h"
+#include "fileops.h"
+#include "git2/odb_backend.h"
+
+
+static int cmp_objects(git_odb_object *odb_obj, git_rawobj *raw)
+{
+	if (raw->type != git_odb_object_type(odb_obj))
+		return -1;
+
+	if (raw->len != git_odb_object_size(odb_obj))
+		return -1;
+
+	if ((raw->len > 0) && (memcmp(raw->data, git_odb_object_data(odb_obj), raw->len) != 0))
+		return -1;
+
+	return 0;
+}
+
+static git_odb *open_hiredis_odb(void)
+{
+	git_odb *odb;
+	git_odb_backend *hiredis;
+
+	if (git_odb_new(&odb) < GIT_SUCCESS)
+		return NULL;
+
+	if (git_odb_backend_hiredis(&hiredis, "127.0.0.1", 6379) < GIT_SUCCESS)
+		return NULL;
+
+	if (git_odb_add_backend(odb, hiredis, 0) < GIT_SUCCESS)
+		return NULL;
+
+	return odb;
+}
+
+#define TEST_WRITE(PTR) {\
+    git_odb *db; \
+	git_oid id1, id2; \
+    git_odb_object *obj; \
+	db = open_hiredis_odb(); \
+	must_be_true(db != NULL); \
+    must_pass(git_oid_mkstr(&id1, PTR.id)); \
+    must_pass(git_odb_write(&id2, db, PTR##_obj.data, PTR##_obj.len, PTR##_obj.type)); \
+    must_be_true(git_oid_cmp(&id1, &id2) == 0); \
+    must_pass(git_odb_read(&obj, db, &id1)); \
+    must_pass(cmp_objects(obj, &PTR##_obj)); \
+    git_odb_object_close(obj); \
+    git_odb_close(db); \
+}
+
+BEGIN_TEST(hiredis0, "write a commit, read it back (hiredis backend)")
+	TEST_WRITE(commit);
+END_TEST
+
+BEGIN_TEST(hiredis1, "write a tree, read it back (hiredis backend)")
+	TEST_WRITE(tree);
+END_TEST
+
+BEGIN_TEST(hiredis2, "write a tag, read it back (hiredis backend)")
+	TEST_WRITE(tag);
+END_TEST
+
+BEGIN_TEST(hiredis3, "write a zero-byte entry, read it back (hiredis backend)")
+	TEST_WRITE(zero);
+END_TEST
+
+BEGIN_TEST(hiredis4, "write a one-byte entry, read it back (hiredis backend)")
+	TEST_WRITE(one);
+END_TEST
+
+BEGIN_TEST(hiredis5, "write a two-byte entry, read it back (hiredis backend)")
+	TEST_WRITE(two);
+END_TEST
+
+BEGIN_TEST(hiredis6, "write some bytes in an entry, read it back (hiredis backend)")
+	TEST_WRITE(some);
+END_TEST
+
+
+BEGIN_SUITE(hiredis)
+	ADD_TEST(hiredis0);
+	ADD_TEST(hiredis1);
+	ADD_TEST(hiredis2);
+	ADD_TEST(hiredis3);
+	ADD_TEST(hiredis4);
+	ADD_TEST(hiredis5);
+	ADD_TEST(hiredis6);
+END_SUITE
+
+#else /* no hiredis builtin */
+BEGIN_SUITE(hiredis)
+	/* empty */
+END_SUITE
+#endif
diff --git a/tests/test_main.c b/tests/test_main.c
index f2a623a..102688c 100644
--- a/tests/test_main.c
+++ b/tests/test_main.c
@@ -41,6 +41,7 @@ DECLARE_SUITE(tag);
 DECLARE_SUITE(tree);
 DECLARE_SUITE(refs);
 DECLARE_SUITE(sqlite);
+DECLARE_SUITE(hiredis);
 DECLARE_SUITE(repository);
 DECLARE_SUITE(threads);
 
@@ -59,6 +60,7 @@ static libgit2_suite suite_methods[]= {
 	SUITE_NAME(sqlite),
 	SUITE_NAME(repository),
 	SUITE_NAME(threads),
+	SUITE_NAME(hiredis)
 };
 
 #define GIT_SUITE_COUNT (ARRAY_SIZE(suite_methods))
diff --git a/wscript b/wscript
index dd90406..f0b81a0 100644
--- a/wscript
+++ b/wscript
@@ -1,3 +1,4 @@
+from __future__ import with_statement
 from waflib.Context import Context
 from waflib.Build import BuildContext, CleanContext, \
         InstallContext, UninstallContext
@@ -16,7 +17,7 @@ CFLAGS_WIN32_L = ['/RELEASE']  # used for /both/ debug and release builds.
                                # sets the module's checksum in the header.
 CFLAGS_WIN32_L_DBG = ['/DEBUG']
 
-ALL_LIBS = ['crypto', 'pthread', 'sqlite3']
+ALL_LIBS = ['crypto', 'pthread', 'sqlite3', 'hiredis']
 
 def options(opt):
     opt.load('compiler_c')
@@ -31,6 +32,8 @@ PPC optimized version (ppc) or the SHA1 functions from OpenSSL (openssl)")
         help='Select target architecture (ia64, x64, x86, x86_amd64, x86_ia64)')
     opt.add_option('--with-sqlite', action='store_true', default=False,
         dest='use_sqlite', help='Enable sqlite support')
+    opt.add_option('--with-hiredis', action='store_true', default=False,
+        dest='use_hiredis', help='Enable redis support using hiredis')
     opt.add_option('--threadsafe', action='store_true', default=False,
         help='Make libgit2 thread-safe (requires pthreads)')
 
@@ -72,6 +75,12 @@ def configure(conf):
         lib='sqlite3', uselib_store='sqlite3', install_path=None, mandatory=False):
         conf.env.DEFINES += ['GIT2_SQLITE_BACKEND']
 
+    # check for hiredis
+    if conf.options.use_hiredis and conf.check_cc(
+        lib='hiredis', uselib_store='hiredis', install_path=None, mandatory=False):
+        conf.env.DEFINES += ['GIT2_HIREDIS_BACKEND']
+
+
     if conf.options.sha1 not in ['openssl', 'ppc', 'builtin']:
         conf.fatal('Invalid SHA1 option')