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object-file: split out logic regarding hash algorithms
While we have a "hash.h" header, the actual implementation of the subsystem is hosted by "object-file.c". This makes it harder than necessary to find the actual implementation of the hash subsystem and intermingles the different concerns with one another. Split out the implementation of hash algorithms into a new, separate "hash.c" file. Signed-off-by: Patrick Steinhardt <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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-277
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4 files changed

+285
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‎Makefile‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1041,6 +1041,7 @@ LIB_OBJS += gpg-interface.o
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LIB_OBJS += graph.o
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LIB_OBJS += grep.o
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LIB_OBJS += hash-lookup.o
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LIB_OBJS += hash.o
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LIB_OBJS += hashmap.o
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LIB_OBJS += help.o
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LIB_OBJS += hex.o

‎hash.c‎

Lines changed: 283 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,283 @@
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#define USE_THE_REPOSITORY_VARIABLE
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#define DISABLE_SIGN_COMPARE_WARNINGS
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#include "git-compat-util.h"
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#include "hash.h"
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#include "hex.h"
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static const struct object_id empty_tree_oid = {
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.hash = {
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0x4b, 0x82, 0x5d, 0xc6, 0x42, 0xcb, 0x6e, 0xb9, 0xa0, 0x60,
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0xe5, 0x4b, 0xf8, 0xd6, 0x92, 0x88, 0xfb, 0xee, 0x49, 0x04
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},
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.algo = GIT_HASH_SHA1,
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};
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static const struct object_id empty_blob_oid = {
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.hash = {
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0xe6, 0x9d, 0xe2, 0x9b, 0xb2, 0xd1, 0xd6, 0x43, 0x4b, 0x8b,
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0x29, 0xae, 0x77, 0x5a, 0xd8, 0xc2, 0xe4, 0x8c, 0x53, 0x91
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},
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.algo = GIT_HASH_SHA1,
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};
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static const struct object_id null_oid_sha1 = {
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.hash = {0},
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.algo = GIT_HASH_SHA1,
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};
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static const struct object_id empty_tree_oid_sha256 = {
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.hash = {
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0x6e, 0xf1, 0x9b, 0x41, 0x22, 0x5c, 0x53, 0x69, 0xf1, 0xc1,
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0x04, 0xd4, 0x5d, 0x8d, 0x85, 0xef, 0xa9, 0xb0, 0x57, 0xb5,
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0x3b, 0x14, 0xb4, 0xb9, 0xb9, 0x39, 0xdd, 0x74, 0xde, 0xcc,
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0x53, 0x21
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},
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.algo = GIT_HASH_SHA256,
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};
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static const struct object_id empty_blob_oid_sha256 = {
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.hash = {
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0x47, 0x3a, 0x0f, 0x4c, 0x3b, 0xe8, 0xa9, 0x36, 0x81, 0xa2,
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0x67, 0xe3, 0xb1, 0xe9, 0xa7, 0xdc, 0xda, 0x11, 0x85, 0x43,
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0x6f, 0xe1, 0x41, 0xf7, 0x74, 0x91, 0x20, 0xa3, 0x03, 0x72,
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0x18, 0x13
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},
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.algo = GIT_HASH_SHA256,
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};
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static const struct object_id null_oid_sha256 = {
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.hash = {0},
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.algo = GIT_HASH_SHA256,
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};
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static void git_hash_sha1_init(struct git_hash_ctx *ctx)
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{
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ctx->algop = &hash_algos[GIT_HASH_SHA1];
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git_SHA1_Init(&ctx->state.sha1);
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}
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static void git_hash_sha1_clone(struct git_hash_ctx *dst, const struct git_hash_ctx *src)
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{
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dst->algop = src->algop;
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git_SHA1_Clone(&dst->state.sha1, &src->state.sha1);
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}
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static void git_hash_sha1_update(struct git_hash_ctx *ctx, const void *data, size_t len)
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{
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git_SHA1_Update(&ctx->state.sha1, data, len);
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}
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static void git_hash_sha1_final(unsigned char *hash, struct git_hash_ctx *ctx)
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{
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git_SHA1_Final(hash, &ctx->state.sha1);
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}
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static void git_hash_sha1_final_oid(struct object_id *oid, struct git_hash_ctx *ctx)
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{
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git_SHA1_Final(oid->hash, &ctx->state.sha1);
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memset(oid->hash + GIT_SHA1_RAWSZ, 0, GIT_MAX_RAWSZ - GIT_SHA1_RAWSZ);
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oid->algo = GIT_HASH_SHA1;
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}
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static void git_hash_sha1_init_unsafe(struct git_hash_ctx *ctx)
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{
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ctx->algop = unsafe_hash_algo(&hash_algos[GIT_HASH_SHA1]);
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git_SHA1_Init_unsafe(&ctx->state.sha1_unsafe);
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}
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static void git_hash_sha1_clone_unsafe(struct git_hash_ctx *dst, const struct git_hash_ctx *src)
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{
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dst->algop = src->algop;
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git_SHA1_Clone_unsafe(&dst->state.sha1_unsafe, &src->state.sha1_unsafe);
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}
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static void git_hash_sha1_update_unsafe(struct git_hash_ctx *ctx, const void *data,
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size_t len)
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{
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git_SHA1_Update_unsafe(&ctx->state.sha1_unsafe, data, len);
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}
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static void git_hash_sha1_final_unsafe(unsigned char *hash, struct git_hash_ctx *ctx)
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{
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git_SHA1_Final_unsafe(hash, &ctx->state.sha1_unsafe);
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}
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static void git_hash_sha1_final_oid_unsafe(struct object_id *oid, struct git_hash_ctx *ctx)
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{
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git_SHA1_Final_unsafe(oid->hash, &ctx->state.sha1_unsafe);
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memset(oid->hash + GIT_SHA1_RAWSZ, 0, GIT_MAX_RAWSZ - GIT_SHA1_RAWSZ);
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oid->algo = GIT_HASH_SHA1;
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}
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static void git_hash_sha256_init(struct git_hash_ctx *ctx)
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{
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ctx->algop = unsafe_hash_algo(&hash_algos[GIT_HASH_SHA256]);
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git_SHA256_Init(&ctx->state.sha256);
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}
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static void git_hash_sha256_clone(struct git_hash_ctx *dst, const struct git_hash_ctx *src)
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{
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dst->algop = src->algop;
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git_SHA256_Clone(&dst->state.sha256, &src->state.sha256);
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}
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static void git_hash_sha256_update(struct git_hash_ctx *ctx, const void *data, size_t len)
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{
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git_SHA256_Update(&ctx->state.sha256, data, len);
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}
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static void git_hash_sha256_final(unsigned char *hash, struct git_hash_ctx *ctx)
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{
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git_SHA256_Final(hash, &ctx->state.sha256);
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}
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static void git_hash_sha256_final_oid(struct object_id *oid, struct git_hash_ctx *ctx)
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{
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git_SHA256_Final(oid->hash, &ctx->state.sha256);
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/*
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* This currently does nothing, so the compiler should optimize it out,
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* but keep it in case we extend the hash size again.
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*/
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memset(oid->hash + GIT_SHA256_RAWSZ, 0, GIT_MAX_RAWSZ - GIT_SHA256_RAWSZ);
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oid->algo = GIT_HASH_SHA256;
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}
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static void git_hash_unknown_init(struct git_hash_ctx *ctx UNUSED)
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{
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BUG("trying to init unknown hash");
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}
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static void git_hash_unknown_clone(struct git_hash_ctx *dst UNUSED,
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const struct git_hash_ctx *src UNUSED)
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{
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BUG("trying to clone unknown hash");
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}
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static void git_hash_unknown_update(struct git_hash_ctx *ctx UNUSED,
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const void *data UNUSED,
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size_t len UNUSED)
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{
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BUG("trying to update unknown hash");
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}
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static void git_hash_unknown_final(unsigned char *hash UNUSED,
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struct git_hash_ctx *ctx UNUSED)
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{
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BUG("trying to finalize unknown hash");
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}
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static void git_hash_unknown_final_oid(struct object_id *oid UNUSED,
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struct git_hash_ctx *ctx UNUSED)
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{
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BUG("trying to finalize unknown hash");
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}
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static const struct git_hash_algo sha1_unsafe_algo = {
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.name = "sha1",
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.format_id = GIT_SHA1_FORMAT_ID,
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.rawsz = GIT_SHA1_RAWSZ,
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.hexsz = GIT_SHA1_HEXSZ,
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.blksz = GIT_SHA1_BLKSZ,
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.init_fn = git_hash_sha1_init_unsafe,
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.clone_fn = git_hash_sha1_clone_unsafe,
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.update_fn = git_hash_sha1_update_unsafe,
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.final_fn = git_hash_sha1_final_unsafe,
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.final_oid_fn = git_hash_sha1_final_oid_unsafe,
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.empty_tree = &empty_tree_oid,
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.empty_blob = &empty_blob_oid,
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.null_oid = &null_oid_sha1,
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};
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const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
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{
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.name = NULL,
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.format_id = 0x00000000,
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.rawsz = 0,
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.hexsz = 0,
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.blksz = 0,
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.init_fn = git_hash_unknown_init,
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.clone_fn = git_hash_unknown_clone,
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.update_fn = git_hash_unknown_update,
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.final_fn = git_hash_unknown_final,
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.final_oid_fn = git_hash_unknown_final_oid,
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.empty_tree = NULL,
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.empty_blob = NULL,
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.null_oid = NULL,
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},
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{
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.name = "sha1",
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.format_id = GIT_SHA1_FORMAT_ID,
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.rawsz = GIT_SHA1_RAWSZ,
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.hexsz = GIT_SHA1_HEXSZ,
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.blksz = GIT_SHA1_BLKSZ,
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.init_fn = git_hash_sha1_init,
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.clone_fn = git_hash_sha1_clone,
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.update_fn = git_hash_sha1_update,
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.final_fn = git_hash_sha1_final,
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.final_oid_fn = git_hash_sha1_final_oid,
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.unsafe = &sha1_unsafe_algo,
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.empty_tree = &empty_tree_oid,
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.empty_blob = &empty_blob_oid,
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.null_oid = &null_oid_sha1,
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},
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{
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.name = "sha256",
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.format_id = GIT_SHA256_FORMAT_ID,
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.rawsz = GIT_SHA256_RAWSZ,
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.hexsz = GIT_SHA256_HEXSZ,
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.blksz = GIT_SHA256_BLKSZ,
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.init_fn = git_hash_sha256_init,
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.clone_fn = git_hash_sha256_clone,
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.update_fn = git_hash_sha256_update,
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.final_fn = git_hash_sha256_final,
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.final_oid_fn = git_hash_sha256_final_oid,
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.empty_tree = &empty_tree_oid_sha256,
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.empty_blob = &empty_blob_oid_sha256,
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.null_oid = &null_oid_sha256,
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}
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};
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const struct object_id *null_oid(void)
237+
{
238+
return the_hash_algo->null_oid;
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}
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const char *empty_tree_oid_hex(const struct git_hash_algo *algop)
242+
{
243+
static char buf[GIT_MAX_HEXSZ + 1];
244+
return oid_to_hex_r(buf, algop->empty_tree);
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}
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int hash_algo_by_name(const char *name)
248+
{
249+
int i;
250+
if (!name)
251+
return GIT_HASH_UNKNOWN;
252+
for (i = 1; i < GIT_HASH_NALGOS; i++)
253+
if (!strcmp(name, hash_algos[i].name))
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return i;
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return GIT_HASH_UNKNOWN;
256+
}
257+
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int hash_algo_by_id(uint32_t format_id)
259+
{
260+
int i;
261+
for (i = 1; i < GIT_HASH_NALGOS; i++)
262+
if (format_id == hash_algos[i].format_id)
263+
return i;
264+
return GIT_HASH_UNKNOWN;
265+
}
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int hash_algo_by_length(int len)
268+
{
269+
int i;
270+
for (i = 1; i < GIT_HASH_NALGOS; i++)
271+
if (len == hash_algos[i].rawsz)
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return i;
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return GIT_HASH_UNKNOWN;
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}
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const struct git_hash_algo *unsafe_hash_algo(const struct git_hash_algo *algop)
277+
{
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/* If we have a faster "unsafe" implementation, use that. */
279+
if (algop->unsafe)
280+
return algop->unsafe;
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/* Otherwise use the default one. */
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return algop;
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}

‎meson.build‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -310,6 +310,7 @@ libgit_sources = [
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'graph.c',
311311
'grep.c',
312312
'hash-lookup.c',
313+
'hash.c',
313314
'hashmap.c',
314315
'help.c',
315316
'hex.c',

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