summaryrefslogtreecommitdiffstats
path: root/hash-ll.h
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-09 13:34:27 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-09 13:34:27 +0000
commit4dbdc42d9e7c3968ff7f690d00680419c9b8cb0f (patch)
tree47c1d492e9c956c1cd2b74dbd3b9d8b0db44dc4e /hash-ll.h
parentInitial commit. (diff)
downloadgit-4dbdc42d9e7c3968ff7f690d00680419c9b8cb0f.tar.xz
git-4dbdc42d9e7c3968ff7f690d00680419c9b8cb0f.zip
Adding upstream version 1:2.43.0.upstream/1%2.43.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'hash-ll.h')
-rw-r--r--hash-ll.h309
1 files changed, 309 insertions, 0 deletions
diff --git a/hash-ll.h b/hash-ll.h
new file mode 100644
index 0000000..10d84cc
--- /dev/null
+++ b/hash-ll.h
@@ -0,0 +1,309 @@
+#ifndef HASH_LL_H
+#define HASH_LL_H
+
+#if defined(SHA1_APPLE)
+#include <CommonCrypto/CommonDigest.h>
+#elif defined(SHA1_OPENSSL)
+# include <openssl/sha.h>
+# if defined(OPENSSL_API_LEVEL) && OPENSSL_API_LEVEL >= 3
+# define SHA1_NEEDS_CLONE_HELPER
+# include "sha1/openssl.h"
+# endif
+#elif defined(SHA1_DC)
+#include "sha1dc_git.h"
+#else /* SHA1_BLK */
+#include "block-sha1/sha1.h"
+#endif
+
+#if defined(SHA256_NETTLE)
+#include "sha256/nettle.h"
+#elif defined(SHA256_GCRYPT)
+#define SHA256_NEEDS_CLONE_HELPER
+#include "sha256/gcrypt.h"
+#elif defined(SHA256_OPENSSL)
+# include <openssl/sha.h>
+# if defined(OPENSSL_API_LEVEL) && OPENSSL_API_LEVEL >= 3
+# define SHA256_NEEDS_CLONE_HELPER
+# include "sha256/openssl.h"
+# endif
+#else
+#include "sha256/block/sha256.h"
+#endif
+
+#ifndef platform_SHA_CTX
+/*
+ * platform's underlying implementation of SHA-1; could be OpenSSL,
+ * blk_SHA, Apple CommonCrypto, etc... Note that the relevant
+ * SHA-1 header may have already defined platform_SHA_CTX for our
+ * own implementations like block-sha1, so we list
+ * the default for OpenSSL compatible SHA-1 implementations here.
+ */
+#define platform_SHA_CTX SHA_CTX
+#define platform_SHA1_Init SHA1_Init
+#define platform_SHA1_Update SHA1_Update
+#define platform_SHA1_Final SHA1_Final
+#endif
+
+#define git_SHA_CTX platform_SHA_CTX
+#define git_SHA1_Init platform_SHA1_Init
+#define git_SHA1_Update platform_SHA1_Update
+#define git_SHA1_Final platform_SHA1_Final
+
+#ifdef platform_SHA1_Clone
+#define git_SHA1_Clone platform_SHA1_Clone
+#endif
+
+#ifndef platform_SHA256_CTX
+#define platform_SHA256_CTX SHA256_CTX
+#define platform_SHA256_Init SHA256_Init
+#define platform_SHA256_Update SHA256_Update
+#define platform_SHA256_Final SHA256_Final
+#endif
+
+#define git_SHA256_CTX platform_SHA256_CTX
+#define git_SHA256_Init platform_SHA256_Init
+#define git_SHA256_Update platform_SHA256_Update
+#define git_SHA256_Final platform_SHA256_Final
+
+#ifdef platform_SHA256_Clone
+#define git_SHA256_Clone platform_SHA256_Clone
+#endif
+
+#ifdef SHA1_MAX_BLOCK_SIZE
+#include "compat/sha1-chunked.h"
+#undef git_SHA1_Update
+#define git_SHA1_Update git_SHA1_Update_Chunked
+#endif
+
+#ifndef SHA1_NEEDS_CLONE_HELPER
+static inline void git_SHA1_Clone(git_SHA_CTX *dst, const git_SHA_CTX *src)
+{
+ memcpy(dst, src, sizeof(*dst));
+}
+#endif
+
+#ifndef SHA256_NEEDS_CLONE_HELPER
+static inline void git_SHA256_Clone(git_SHA256_CTX *dst, const git_SHA256_CTX *src)
+{
+ memcpy(dst, src, sizeof(*dst));
+}
+#endif
+
+/*
+ * Note that these constants are suitable for indexing the hash_algos array and
+ * comparing against each other, but are otherwise arbitrary, so they should not
+ * be exposed to the user or serialized to disk. To know whether a
+ * git_hash_algo struct points to some usable hash function, test the format_id
+ * field for being non-zero. Use the name field for user-visible situations and
+ * the format_id field for fixed-length fields on disk.
+ */
+/* An unknown hash function. */
+#define GIT_HASH_UNKNOWN 0
+/* SHA-1 */
+#define GIT_HASH_SHA1 1
+/* SHA-256 */
+#define GIT_HASH_SHA256 2
+/* Number of algorithms supported (including unknown). */
+#define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1)
+
+/* "sha1", big-endian */
+#define GIT_SHA1_FORMAT_ID 0x73686131
+
+/* The length in bytes and in hex digits of an object name (SHA-1 value). */
+#define GIT_SHA1_RAWSZ 20
+#define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
+/* The block size of SHA-1. */
+#define GIT_SHA1_BLKSZ 64
+
+/* "s256", big-endian */
+#define GIT_SHA256_FORMAT_ID 0x73323536
+
+/* The length in bytes and in hex digits of an object name (SHA-256 value). */
+#define GIT_SHA256_RAWSZ 32
+#define GIT_SHA256_HEXSZ (2 * GIT_SHA256_RAWSZ)
+/* The block size of SHA-256. */
+#define GIT_SHA256_BLKSZ 64
+
+/* The length in byte and in hex digits of the largest possible hash value. */
+#define GIT_MAX_RAWSZ GIT_SHA256_RAWSZ
+#define GIT_MAX_HEXSZ GIT_SHA256_HEXSZ
+/* The largest possible block size for any supported hash. */
+#define GIT_MAX_BLKSZ GIT_SHA256_BLKSZ
+
+struct object_id {
+ unsigned char hash[GIT_MAX_RAWSZ];
+ int algo; /* XXX requires 4-byte alignment */
+};
+
+#define GET_OID_QUIETLY 01
+#define GET_OID_COMMIT 02
+#define GET_OID_COMMITTISH 04
+#define GET_OID_TREE 010
+#define GET_OID_TREEISH 020
+#define GET_OID_BLOB 040
+#define GET_OID_FOLLOW_SYMLINKS 0100
+#define GET_OID_RECORD_PATH 0200
+#define GET_OID_ONLY_TO_DIE 04000
+#define GET_OID_REQUIRE_PATH 010000
+
+#define GET_OID_DISAMBIGUATORS \
+ (GET_OID_COMMIT | GET_OID_COMMITTISH | \
+ GET_OID_TREE | GET_OID_TREEISH | \
+ GET_OID_BLOB)
+
+enum get_oid_result {
+ FOUND = 0,
+ MISSING_OBJECT = -1, /* The requested object is missing */
+ SHORT_NAME_AMBIGUOUS = -2,
+ /* The following only apply when symlinks are followed */
+ DANGLING_SYMLINK = -4, /*
+ * The initial symlink is there, but
+ * (transitively) points to a missing
+ * in-tree file
+ */
+ SYMLINK_LOOP = -5,
+ NOT_DIR = -6, /*
+ * Somewhere along the symlink chain, a path is
+ * requested which contains a file as a
+ * non-final element.
+ */
+};
+
+/* A suitably aligned type for stack allocations of hash contexts. */
+union git_hash_ctx {
+ git_SHA_CTX sha1;
+ git_SHA256_CTX sha256;
+};
+typedef union git_hash_ctx git_hash_ctx;
+
+typedef void (*git_hash_init_fn)(git_hash_ctx *ctx);
+typedef void (*git_hash_clone_fn)(git_hash_ctx *dst, const git_hash_ctx *src);
+typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len);
+typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx);
+typedef void (*git_hash_final_oid_fn)(struct object_id *oid, git_hash_ctx *ctx);
+
+struct git_hash_algo {
+ /*
+ * The name of the algorithm, as appears in the config file and in
+ * messages.
+ */
+ const char *name;
+
+ /* A four-byte version identifier, used in pack indices. */
+ uint32_t format_id;
+
+ /* The length of the hash in binary. */
+ size_t rawsz;
+
+ /* The length of the hash in hex characters. */
+ size_t hexsz;
+
+ /* The block size of the hash. */
+ size_t blksz;
+
+ /* The hash initialization function. */
+ git_hash_init_fn init_fn;
+
+ /* The hash context cloning function. */
+ git_hash_clone_fn clone_fn;
+
+ /* The hash update function. */
+ git_hash_update_fn update_fn;
+
+ /* The hash finalization function. */
+ git_hash_final_fn final_fn;
+
+ /* The hash finalization function for object IDs. */
+ git_hash_final_oid_fn final_oid_fn;
+
+ /* The OID of the empty tree. */
+ const struct object_id *empty_tree;
+
+ /* The OID of the empty blob. */
+ const struct object_id *empty_blob;
+
+ /* The all-zeros OID. */
+ const struct object_id *null_oid;
+};
+extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS];
+
+/*
+ * Return a GIT_HASH_* constant based on the name. Returns GIT_HASH_UNKNOWN if
+ * the name doesn't match a known algorithm.
+ */
+int hash_algo_by_name(const char *name);
+/* Identical, except based on the format ID. */
+int hash_algo_by_id(uint32_t format_id);
+/* Identical, except based on the length. */
+int hash_algo_by_length(int len);
+/* Identical, except for a pointer to struct git_hash_algo. */
+static inline int hash_algo_by_ptr(const struct git_hash_algo *p)
+{
+ return p - hash_algos;
+}
+
+const struct object_id *null_oid(void);
+
+static inline int hashcmp_algop(const unsigned char *sha1, const unsigned char *sha2, const struct git_hash_algo *algop)
+{
+ /*
+ * Teach the compiler that there are only two possibilities of hash size
+ * here, so that it can optimize for this case as much as possible.
+ */
+ if (algop->rawsz == GIT_MAX_RAWSZ)
+ return memcmp(sha1, sha2, GIT_MAX_RAWSZ);
+ return memcmp(sha1, sha2, GIT_SHA1_RAWSZ);
+}
+
+static inline int hasheq_algop(const unsigned char *sha1, const unsigned char *sha2, const struct git_hash_algo *algop)
+{
+ /*
+ * We write this here instead of deferring to hashcmp so that the
+ * compiler can properly inline it and avoid calling memcmp.
+ */
+ if (algop->rawsz == GIT_MAX_RAWSZ)
+ return !memcmp(sha1, sha2, GIT_MAX_RAWSZ);
+ return !memcmp(sha1, sha2, GIT_SHA1_RAWSZ);
+}
+
+static inline void oidcpy(struct object_id *dst, const struct object_id *src)
+{
+ memcpy(dst->hash, src->hash, GIT_MAX_RAWSZ);
+ dst->algo = src->algo;
+}
+
+static inline struct object_id *oiddup(const struct object_id *src)
+{
+ struct object_id *dst = xmalloc(sizeof(struct object_id));
+ oidcpy(dst, src);
+ return dst;
+}
+
+static inline void oid_set_algo(struct object_id *oid, const struct git_hash_algo *algop)
+{
+ oid->algo = hash_algo_by_ptr(algop);
+}
+
+/*
+ * Converts a cryptographic hash (e.g. SHA-1) into an int-sized hash code
+ * for use in hash tables. Cryptographic hashes are supposed to have
+ * uniform distribution, so in contrast to `memhash()`, this just copies
+ * the first `sizeof(int)` bytes without shuffling any bits. Note that
+ * the results will be different on big-endian and little-endian
+ * platforms, so they should not be stored or transferred over the net.
+ */
+static inline unsigned int oidhash(const struct object_id *oid)
+{
+ /*
+ * Equivalent to 'return *(unsigned int *)oid->hash;', but safe on
+ * platforms that don't support unaligned reads.
+ */
+ unsigned int hash;
+ memcpy(&hash, oid->hash, sizeof(hash));
+ return hash;
+}
+
+const char *empty_tree_oid_hex(void);
+const char *empty_blob_oid_hex(void);
+
+#endif