From: Andre Noll <maan@tuebingen.mpg.de>
Date: Wed, 19 Apr 2017 13:12:44 +0000 (+0200)
Subject: Prepare hash_function() for multiple hash algorithms.
X-Git-Tag: v0.2.0~4^2~2
X-Git-Url: http://git.tuebingen.mpg.de/?p=osl.git;a=commitdiff_plain;h=6811bf3ef3f157e82c189f22e0b5cedd8a8ba1db

Prepare hash_function() for multiple hash algorithms.

In order to transparently support more than one hash function in the
future, we now pass the table version to hash_function(). The version
is always one at the moment, and only the sha1 hash is implemented
so far.
---

diff --git a/fsck.c b/fsck.c
index 8a32aba..42312d9 100644
--- a/fsck.c
+++ b/fsck.c
@@ -718,7 +718,7 @@ static int check_disk_storage_presence(struct osl_table *t)
 		ret = get_mapped_object(t, dsnc, i, &obj);
 		if (ret < 0)
 			return ret;
-		hash_object(&obj, hashes + i * HASH_SIZE);
+		hash_object(t, &obj, hashes + i * HASH_SIZE);
 		hash_obj.data = hashes + i * HASH_SIZE;
 		osl_add_row(hash_tree_table, &hash_obj);
 		ds_name = disk_storage_name_of_hash(t, hashes + i * HASH_SIZE);
@@ -1041,7 +1041,7 @@ static int dump_row(struct osl_table *t, unsigned row_num, const char *row_dir)
 	ret = get_mapped_object(t, dsnc, row_num, &obj);
 	if (ret < 0)
 		return ret;
-	hash_object(&obj, hash);
+	hash_object(t, &obj, hash);
 	ds_name = disk_storage_name_of_hash(t, hash);
 	FOR_EACH_DISK_STORAGE_COLUMN(i, t, cd) {
 		filename = disk_storage_path(t, i, ds_name);
diff --git a/hash.h b/hash.h
index 6244d08..0815338 100644
--- a/hash.h
+++ b/hash.h
@@ -16,8 +16,12 @@
 
 void sha1_hash(const char *data, unsigned long len, unsigned char *sha1);
 
-/** Our own sha1 implementation, see sha1.c. */
-#define hash_function sha1_hash
+static inline void hash_function(uint8_t table_version, const char *data,
+		unsigned long len, unsigned char *result)
+{
+	assert(table_version == 1);
+	sha1_hash(data, len, result);
+}
 
 /**
  * Compare two hashes.
diff --git a/osl.c b/osl.c
index 40b0a24..8e19bc4 100644
--- a/osl.c
+++ b/osl.c
@@ -168,7 +168,7 @@ static char *disk_storage_name_of_object(const struct osl_table *t,
 	const struct osl_object *obj)
 {
 	HASH_TYPE hash[HASH_SIZE];
-	hash_object(obj, hash);
+	hash_object(t, obj, hash);
 	return disk_storage_name_of_hash(t, hash);
 }
 
@@ -186,9 +186,10 @@ static int disk_storage_name_of_row(const struct osl_table *t,
 	return -E_OSL_NOMEM;
 }
 
-static void column_name_hash(const char *col_name, HASH_TYPE *hash)
+static void column_name_hash(const struct osl_table *t, const char *col_name,
+		HASH_TYPE *hash)
 {
-	hash_function(col_name, strlen(col_name), hash);
+	hash_function(t->version, col_name, strlen(col_name), hash);
 }
 
 static int init_column_descriptions(struct osl_table *t)
@@ -553,7 +554,7 @@ __export int osl_create_table(const struct osl_table_description *desc)
 			if (ret < 0)
 				goto out;
 		}
-		column_name_hash(cd->name, t->columns[i].name_hash);
+		column_name_hash(t, cd->name, t->columns[i].name_hash);
 		ret = -E_OSL_NOMEM;
 		filename = column_filename(t, i);
 		if (!filename)
@@ -724,7 +725,7 @@ int map_table(struct osl_table *t, enum map_table_flags flags)
 	FOR_EACH_COLUMN(i, t->desc, cd) {
 		if (cd->storage_type == OSL_NO_STORAGE)
 			continue;
-		column_name_hash(cd->name, t->columns[i].name_hash);
+		column_name_hash(t, cd->name, t->columns[i].name_hash);
 		if (num_rows > 0 && cd->storage_type == OSL_MAPPED_STORAGE) {
 			ret = map_column(t, i);
 			if (ret < 0)
diff --git a/osl_core.h b/osl_core.h
index 9879b1e..91489c9 100644
--- a/osl_core.h
+++ b/osl_core.h
@@ -456,12 +456,14 @@ _static_inline_ struct osl_row *get_row_pointer(const struct rb_node *node,
 /**
  * Compute a cryptographic hash of an osl object.
  *
+ * \param t Determines the hash function to use.
  * \param obj the Object to compute the hash value from.
  * \param hash Result is returned here.
  */
-_static_inline_ void hash_object(const struct osl_object *obj, HASH_TYPE *hash)
+_static_inline_ void hash_object(const struct osl_table *t,
+		const struct osl_object *obj, HASH_TYPE *hash)
 {
-	hash_function(obj->data, obj->size, hash);
+	hash_function(t->version, obj->data, obj->size, hash);
 }
 
 /**