Skip to main content

Browse the archive

Revision 663b2b1b90bf76275044824ddeca96aaec240f09 authored by Derrick Stolee on 17 September 2020, 18:11:46 UTC, committed by Junio C Hamano on 17 September 2020, 18:30:05 UTC 
maintenance: add commit-graph task
 
The first new task in the 'git maintenance' builtin is the
'commit-graph' task. This updates the commit-graph file
incrementally with the command

	git commit-graph write --reachable --split

By writing an incremental commit-graph file using the "--split"
option we minimize the disruption from this operation. The default
behavior is to merge layers until the new "top" layer is less than
half the size of the layer below. This provides quick writes most
of the time, with the longer writes following a power law
distribution.

Most importantly, concurrent Git processes only look at the
commit-graph-chain file for a very short amount of time, so they
will verly likely not be holding a handle to the file when we try
to replace it. (This only matters on Windows.)

If a concurrent process reads the old commit-graph-chain file, but
our job expires some of the .graph files before they can be read,
then those processes will see a warning message (but not fail).
This could be avoided by a future update to use the --expire-time
argument when writing the commit-graph.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 3103e98
Raw File
hex.c 
#include "cache.h"

const signed char hexval_table[256] = {
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 00-07 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 08-0f */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 10-17 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 18-1f */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 20-27 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 28-2f */
	  0,  1,  2,  3,  4,  5,  6,  7,		/* 30-37 */
	  8,  9, -1, -1, -1, -1, -1, -1,		/* 38-3f */
	 -1, 10, 11, 12, 13, 14, 15, -1,		/* 40-47 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 48-4f */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 50-57 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 58-5f */
	 -1, 10, 11, 12, 13, 14, 15, -1,		/* 60-67 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 68-67 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 70-77 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 78-7f */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 80-87 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 88-8f */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 90-97 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* 98-9f */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* a0-a7 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* a8-af */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* b0-b7 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* b8-bf */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* c0-c7 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* c8-cf */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* d0-d7 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* d8-df */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* e0-e7 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* e8-ef */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* f0-f7 */
	 -1, -1, -1, -1, -1, -1, -1, -1,		/* f8-ff */
};

int hex_to_bytes(unsigned char *binary, const char *hex, size_t len)
{
	for (; len; len--, hex += 2) {
		unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);

		if (val & ~0xff)
			return -1;
		*binary++ = val;
	}
	return 0;
}

static int get_hash_hex_algop(const char *hex, unsigned char *hash,
			      const struct git_hash_algo *algop)
{
	int i;
	for (i = 0; i < algop->rawsz; i++) {
		int val = hex2chr(hex);
		if (val < 0)
			return -1;
		*hash++ = val;
		hex += 2;
	}
	return 0;
}

int get_sha1_hex(const char *hex, unsigned char *sha1)
{
	return get_hash_hex_algop(hex, sha1, the_hash_algo);
}

int get_oid_hex_algop(const char *hex, struct object_id *oid,
		      const struct git_hash_algo *algop)
{
	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);
}

int parse_oid_hex_algop(const char *hex, struct object_id *oid,
			const char **end,
			const struct git_hash_algo *algop)
{
	int ret = get_hash_hex_algop(hex, oid->hash, algop);
	if (!ret)
		*end = hex + algop->hexsz;
	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);
}

char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash,
			  const struct git_hash_algo *algop)
{
	static const char hex[] = "0123456789abcdef";
	char *buf = buffer;
	int i;

	for (i = 0; i < algop->rawsz; i++) {
		unsigned int val = *hash++;
		*buf++ = hex[val >> 4];
		*buf++ = hex[val & 0xf];
	}
	*buf = '\0';

	return buffer;
}

char *oid_to_hex_r(char *buffer, const struct object_id *oid)
{
	return hash_to_hex_algop_r(buffer, oid->hash, the_hash_algo);
}

char *hash_to_hex_algop(const unsigned char *hash, const struct git_hash_algo *algop)
{
	static int bufno;
	static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
	bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
	return hash_to_hex_algop_r(hexbuffer[bufno], hash, algop);
}

char *hash_to_hex(const unsigned char *hash)
{
	return hash_to_hex_algop(hash, the_hash_algo);
}

char *oid_to_hex(const struct object_id *oid)
{
	return hash_to_hex_algop(oid->hash, the_hash_algo);
}
back to top