git

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#define USE_THE_REPOSITORY_VARIABLE
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#include "git-compat-util.h"
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#include "config.h"
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#include "strbuf.h"
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#include "string-list.h"
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#include "versioncmp.h"
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/*
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 * versioncmp(): copied from string/strverscmp.c in glibc commit
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 * ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
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 * style. The implementation is under LGPL-2.1 and Git relicenses it
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 * to GPLv2.
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 */
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/*
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 * states: S_N: normal, S_I: comparing integral part, S_F: comparing
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 * fractionnal parts, S_Z: idem but with leading Zeroes only
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 */
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#define  S_N    0x0
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#define  S_I    0x3
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#define  S_F    0x6
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#define  S_Z    0x9
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/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
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#define  CMP    2
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#define  LEN    3
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static const struct string_list *prereleases;
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static int initialized;
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struct suffix_match {
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	int conf_pos;
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	int start;
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	int len;
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};
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static void find_better_matching_suffix(const char *tagname, const char *suffix,
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					int suffix_len, int start, int conf_pos,
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					struct suffix_match *match)
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{
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	/*
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	 * A better match either starts earlier or starts at the same offset
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	 * but is longer.
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	 */
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	int end = match->len < suffix_len ? match->start : match->start-1;
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	int i;
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	for (i = start; i <= end; i++)
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		if (starts_with(tagname + i, suffix)) {
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			match->conf_pos = conf_pos;
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			match->start = i;
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			match->len = suffix_len;
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			break;
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		}
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}
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/*
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 * off is the offset of the first different character in the two strings
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 * s1 and s2. If either s1 or s2 contains a prerelease suffix containing
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 * that offset or a suffix ends right before that offset, then that
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 * string will be forced to be on top.
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 *
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 * If both s1 and s2 contain a (different) suffix around that position,
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 * their order is determined by the order of those two suffixes in the
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 * configuration.
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 * If any of the strings contains more than one different suffixes around
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 * that position, then that string is sorted according to the contained
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 * suffix which starts at the earliest offset in that string.
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 * If more than one different contained suffixes start at that earliest
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 * offset, then that string is sorted according to the longest of those
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 * suffixes.
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 *
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 * Return non-zero if *diff contains the return value for versioncmp()
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 */
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static int swap_prereleases(const char *s1,
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			    const char *s2,
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			    int off,
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			    int *diff)
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{
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	int i;
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	struct suffix_match match1 = { -1, off, -1 };
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	struct suffix_match match2 = { -1, off, -1 };
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	for (i = 0; i < prereleases->nr; i++) {
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		const char *suffix = prereleases->items[i].string;
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		int start, suffix_len = strlen(suffix);
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		if (suffix_len < off)
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			start = off - suffix_len;
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		else
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			start = 0;
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		find_better_matching_suffix(s1, suffix, suffix_len, start,
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					    i, &match1);
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		find_better_matching_suffix(s2, suffix, suffix_len, start,
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					    i, &match2);
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	}
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	if (match1.conf_pos == -1 && match2.conf_pos == -1)
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		return 0;
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	if (match1.conf_pos == match2.conf_pos)
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		/* Found the same suffix in both, e.g. "-rc" in "v1.0-rcX"
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		 * and "v1.0-rcY": the caller should decide based on "X"
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		 * and "Y". */
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		return 0;
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	if (match1.conf_pos >= 0 && match2.conf_pos >= 0)
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		*diff = match1.conf_pos - match2.conf_pos;
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	else if (match1.conf_pos >= 0)
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		*diff = -1;
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	else /* if (match2.conf_pos >= 0) */
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		*diff = 1;
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	return 1;
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}
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/*
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 * Compare S1 and S2 as strings holding indices/version numbers,
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 * returning less than, equal to or greater than zero if S1 is less
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 * than, equal to or greater than S2 (for more info, see the texinfo
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 * doc).
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 */
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int versioncmp(const char *s1, const char *s2)
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{
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	const unsigned char *p1 = (const unsigned char *) s1;
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	const unsigned char *p2 = (const unsigned char *) s2;
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	unsigned char c1, c2;
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	int state, diff;
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	/*
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	 * Symbol(s)    0       [1-9]   others
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	 * Transition   (10) 0  (01) d  (00) x
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	 */
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	static const uint8_t next_state[] = {
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		/* state    x    d    0  */
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		/* S_N */  S_N, S_I, S_Z,
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		/* S_I */  S_N, S_I, S_I,
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		/* S_F */  S_N, S_F, S_F,
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		/* S_Z */  S_N, S_F, S_Z
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	};
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	static const int8_t result_type[] = {
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		/* state   x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
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		/* S_N */  CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
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		/* S_I */  CMP, -1,  -1,  +1,  LEN, LEN, +1,  LEN, LEN,
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		/* S_F */  CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
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		/* S_Z */  CMP, +1,  +1,  -1,  CMP, CMP, -1,  CMP, CMP
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	};
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	if (p1 == p2)
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		return 0;
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	c1 = *p1++;
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	c2 = *p2++;
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	/* Hint: '0' is a digit too.  */
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	state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
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	while ((diff = c1 - c2) == 0) {
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		if (c1 == '\0')
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			return diff;
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		state = next_state[state];
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		c1 = *p1++;
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		c2 = *p2++;
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		state += (c1 == '0') + (isdigit (c1) != 0);
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	}
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	if (!initialized) {
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		const char *const newk = "versionsort.suffix";
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		const char *const oldk = "versionsort.prereleasesuffix";
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		const struct string_list *newl;
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		const struct string_list *oldl;
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		int new = git_config_get_string_multi(newk, &newl);
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		int old = git_config_get_string_multi(oldk, &oldl);
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		if (!new && !old)
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			warning("ignoring %s because %s is set", oldk, newk);
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		if (!new)
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			prereleases = newl;
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		else if (!old)
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			prereleases = oldl;
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		initialized = 1;
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	}
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	if (prereleases && swap_prereleases(s1, s2, (const char *) p1 - s1 - 1,
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					    &diff))
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		return diff;
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	state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
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	switch (state) {
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	case CMP:
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		return diff;
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	case LEN:
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		while (isdigit (*p1++))
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			if (!isdigit (*p2++))
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				return 1;
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		return isdigit (*p2) ? -1 : diff;
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	default:
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		return state;
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	}
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}
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