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From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: <git@vger.kernel.org>
Subject: [RFC PATCH 02/22] hex: add functions to parse hex object IDs in any algorithm
Date: Mon, 13 Jan 2020 12:47:09 +0000
Message-ID: <20200113124729.3684846-3-sandals@crustytoothpaste.net> (raw)
In-Reply-To: <20200113124729.3684846-1-sandals@crustytoothpaste.net>

There are some places where we need to parse a hex object ID in any
algorithm without knowing beforehand which algorithm is in use. An
example is when parsing fast-import marks.

Add a get_oid_hex_any to parse an object ID and return the algorithm it
belongs to, and additionally add parse_oid_hex_any which is the
equivalent change for parse_oid_hex. If the object is not parseable, we
return GIT_HASH_UNKNOWN.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h | 10 ++++++++++
 hex.c   | 22 ++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/cache.h b/cache.h
index 493d57febe..6c094c3210 100644
--- a/cache.h
+++ b/cache.h
@@ -1522,6 +1522,16 @@ int parse_oid_hex(const char *hex, struct object_id *oid, const char **end);
 int parse_oid_hex_algop(const char *hex, struct object_id *oid, const char **end,
 			const struct git_hash_algo *algo);
 
+
+/*
+ * These functions work like get_oid_hex and parse_oid_hex, but they will parse
+ * a hex value for any algorithm. The algorithm is detected based on the length
+ * and the algorithm in use is returned. If this is not a hex object ID in any
+ * algorithm, returns GIT_HASH_UNKNOWN.
+ */
+int get_oid_hex_any(const char *hex, struct object_id *oid);
+int parse_oid_hex_any(const char *hex, struct object_id *oid, const char **end);
+
 /*
  * This reads short-hand syntax that not only evaluates to a commit
  * object name, but also can act as if the end user spelled the name
diff --git a/hex.c b/hex.c
index 10e24dc2e4..da51e64929 100644
--- a/hex.c
+++ b/hex.c
@@ -72,6 +72,20 @@ int get_oid_hex_algop(const char *hex, struct object_id *oid,
 	return get_hash_hex_algop(hex, oid->hash, algop);
 }
 
+/*
+ * NOTE: This function relies on hash algorithms being in order from shortest
+ * length to longest length.
+ */
+int get_oid_hex_any(const char *hex, struct object_id *oid)
+{
+	int i;
+	for (i = GIT_HASH_NALGOS - 1; i > 0; i--) {
+		if (!get_hash_hex_algop(hex, oid->hash, &hash_algos[i]))
+			return i;
+	}
+	return GIT_HASH_UNKNOWN;
+}
+
 int get_oid_hex(const char *hex, struct object_id *oid)
 {
 	return get_oid_hex_algop(hex, oid, the_hash_algo);
@@ -87,6 +101,14 @@ int parse_oid_hex_algop(const char *hex, struct object_id *oid,
 	return ret;
 }
 
+int parse_oid_hex_any(const char *hex, struct object_id *oid, const char **end)
+{
+	int ret = get_oid_hex_any(hex, oid);
+	if (ret)
+		*end = hex + hash_algos[ret].hexsz;
+	return ret;
+}
+
 int parse_oid_hex(const char *hex, struct object_id *oid, const char **end)
 {
 	return parse_oid_hex_algop(hex, oid, end, the_hash_algo);

  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-13 12:47 [RFC PATCH 00/22] SHA-256 stage 4 implementation, part 1/3 brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 01/22] hex: introduce parsing variants taking hash algorithms brian m. carlson
2020-01-13 12:47 ` brian m. carlson [this message]
2020-01-15 21:40   ` [RFC PATCH 02/22] hex: add functions to parse hex object IDs in any algorithm Junio C Hamano
2020-01-16  0:22     ` brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 03/22] repository: require a build flag to use SHA-256 brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 04/22] t: use hash-specific lookup tables to define test constants brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 05/22] t6300: abstract away SHA-1-specific constants brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 06/22] t6300: make hash algorithm independent brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 07/22] t/helper/test-dump-split-index: initialize git repository brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 08/22] t/helper: initialize repository if necessary brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 09/22] t/helper: make repository tests hash independent brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 10/22] setup: allow check_repository_format to read repository format brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 11/22] builtin/init-db: allow specifying hash algorithm on command line brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 12/22] builtin/init-db: add environment variable for new repo hash brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 13/22] init-db: move writing repo version into a function brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 14/22] worktree: allow repository version 1 brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 15/22] commit: use expected signature header for SHA-256 brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 16/22] gpg-interface: improve interface for parsing tags brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 17/22] tag: store SHA-256 signatures in a header brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 18/22] fast-import: permit reading multiple marks files brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 19/22] fast-import: add helper function for inserting mark object entries brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 20/22] fast-import: make find_marks work on any mark set brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 21/22] fast-import: add a generic function to iterate over marks brian m. carlson
2020-01-13 12:47 ` [RFC PATCH 22/22] fast-import: add options for rewriting submodules brian m. carlson

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