зеркало из https://github.com/microsoft/git.git
1053 строки
26 KiB
C
1053 строки
26 KiB
C
/*
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* GIT - The information manager from hell
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*
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* Copyright (C) Linus Torvalds, 2005
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*/
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#include "cache.h"
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#include "cache-tree.h"
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/* Index extensions.
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*
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* The first letter should be 'A'..'Z' for extensions that are not
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* necessary for a correct operation (i.e. optimization data).
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* When new extensions are added that _needs_ to be understood in
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* order to correctly interpret the index file, pick character that
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* is outside the range, to cause the reader to abort.
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*/
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#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
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#define CACHE_EXT_TREE 0x54524545 /* "TREE" */
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struct cache_entry **active_cache;
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static time_t index_file_timestamp;
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unsigned int active_nr, active_alloc, active_cache_changed;
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struct cache_tree *active_cache_tree;
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static void *cache_mmap;
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static size_t cache_mmap_size;
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/*
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* This only updates the "non-critical" parts of the directory
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* cache, ie the parts that aren't tracked by GIT, and only used
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* to validate the cache.
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*/
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void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
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{
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ce->ce_ctime.sec = htonl(st->st_ctime);
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ce->ce_mtime.sec = htonl(st->st_mtime);
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#ifdef USE_NSEC
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ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
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ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
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#endif
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ce->ce_dev = htonl(st->st_dev);
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ce->ce_ino = htonl(st->st_ino);
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ce->ce_uid = htonl(st->st_uid);
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ce->ce_gid = htonl(st->st_gid);
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ce->ce_size = htonl(st->st_size);
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if (assume_unchanged)
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ce->ce_flags |= htons(CE_VALID);
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}
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static int ce_compare_data(struct cache_entry *ce, struct stat *st)
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{
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int match = -1;
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int fd = open(ce->name, O_RDONLY);
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if (fd >= 0) {
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unsigned char sha1[20];
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if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
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match = hashcmp(sha1, ce->sha1);
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/* index_fd() closed the file descriptor already */
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}
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return match;
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}
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static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
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{
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int match = -1;
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char *target;
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void *buffer;
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unsigned long size;
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enum object_type type;
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int len;
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target = xmalloc(expected_size);
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len = readlink(ce->name, target, expected_size);
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if (len != expected_size) {
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free(target);
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return -1;
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}
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buffer = read_sha1_file(ce->sha1, &type, &size);
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if (!buffer) {
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free(target);
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return -1;
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}
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if (size == expected_size)
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match = memcmp(buffer, target, size);
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free(buffer);
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free(target);
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return match;
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}
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static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
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{
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switch (st->st_mode & S_IFMT) {
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case S_IFREG:
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if (ce_compare_data(ce, st))
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return DATA_CHANGED;
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break;
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case S_IFLNK:
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if (ce_compare_link(ce, xsize_t(st->st_size)))
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return DATA_CHANGED;
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break;
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default:
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return TYPE_CHANGED;
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}
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return 0;
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}
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static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
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{
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unsigned int changed = 0;
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switch (ntohl(ce->ce_mode) & S_IFMT) {
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case S_IFREG:
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changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
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/* We consider only the owner x bit to be relevant for
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* "mode changes"
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*/
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if (trust_executable_bit &&
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(0100 & (ntohl(ce->ce_mode) ^ st->st_mode)))
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changed |= MODE_CHANGED;
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break;
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case S_IFLNK:
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if (!S_ISLNK(st->st_mode) &&
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(has_symlinks || !S_ISREG(st->st_mode)))
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changed |= TYPE_CHANGED;
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break;
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default:
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die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
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}
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if (ce->ce_mtime.sec != htonl(st->st_mtime))
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changed |= MTIME_CHANGED;
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if (ce->ce_ctime.sec != htonl(st->st_ctime))
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changed |= CTIME_CHANGED;
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#ifdef USE_NSEC
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/*
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* nsec seems unreliable - not all filesystems support it, so
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* as long as it is in the inode cache you get right nsec
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* but after it gets flushed, you get zero nsec.
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*/
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if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
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changed |= MTIME_CHANGED;
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if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
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changed |= CTIME_CHANGED;
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#endif
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if (ce->ce_uid != htonl(st->st_uid) ||
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ce->ce_gid != htonl(st->st_gid))
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changed |= OWNER_CHANGED;
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if (ce->ce_ino != htonl(st->st_ino))
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changed |= INODE_CHANGED;
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#ifdef USE_STDEV
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/*
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* st_dev breaks on network filesystems where different
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* clients will have different views of what "device"
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* the filesystem is on
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*/
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if (ce->ce_dev != htonl(st->st_dev))
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changed |= INODE_CHANGED;
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#endif
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if (ce->ce_size != htonl(st->st_size))
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changed |= DATA_CHANGED;
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return changed;
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}
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int ce_match_stat(struct cache_entry *ce, struct stat *st, int options)
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{
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unsigned int changed;
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int ignore_valid = options & 01;
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int assume_racy_is_modified = options & 02;
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/*
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* If it's marked as always valid in the index, it's
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* valid whatever the checked-out copy says.
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*/
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if (!ignore_valid && (ce->ce_flags & htons(CE_VALID)))
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return 0;
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changed = ce_match_stat_basic(ce, st);
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/*
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* Within 1 second of this sequence:
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* echo xyzzy >file && git-update-index --add file
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* running this command:
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* echo frotz >file
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* would give a falsely clean cache entry. The mtime and
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* length match the cache, and other stat fields do not change.
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*
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* We could detect this at update-index time (the cache entry
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* being registered/updated records the same time as "now")
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* and delay the return from git-update-index, but that would
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* effectively mean we can make at most one commit per second,
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* which is not acceptable. Instead, we check cache entries
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* whose mtime are the same as the index file timestamp more
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* carefully than others.
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*/
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if (!changed &&
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index_file_timestamp &&
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index_file_timestamp <= ntohl(ce->ce_mtime.sec)) {
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if (assume_racy_is_modified)
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changed |= DATA_CHANGED;
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else
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changed |= ce_modified_check_fs(ce, st);
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}
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return changed;
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}
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int ce_modified(struct cache_entry *ce, struct stat *st, int really)
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{
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int changed, changed_fs;
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changed = ce_match_stat(ce, st, really);
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if (!changed)
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return 0;
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/*
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* If the mode or type has changed, there's no point in trying
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* to refresh the entry - it's not going to match
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*/
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if (changed & (MODE_CHANGED | TYPE_CHANGED))
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return changed;
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/* Immediately after read-tree or update-index --cacheinfo,
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* the length field is zero. For other cases the ce_size
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* should match the SHA1 recorded in the index entry.
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*/
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if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
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return changed;
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changed_fs = ce_modified_check_fs(ce, st);
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if (changed_fs)
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return changed | changed_fs;
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return 0;
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}
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int base_name_compare(const char *name1, int len1, int mode1,
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const char *name2, int len2, int mode2)
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{
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unsigned char c1, c2;
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int len = len1 < len2 ? len1 : len2;
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int cmp;
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cmp = memcmp(name1, name2, len);
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if (cmp)
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return cmp;
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c1 = name1[len];
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c2 = name2[len];
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if (!c1 && S_ISDIR(mode1))
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c1 = '/';
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if (!c2 && S_ISDIR(mode2))
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c2 = '/';
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return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
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}
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int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
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{
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int len1 = flags1 & CE_NAMEMASK;
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int len2 = flags2 & CE_NAMEMASK;
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int len = len1 < len2 ? len1 : len2;
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int cmp;
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cmp = memcmp(name1, name2, len);
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if (cmp)
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return cmp;
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if (len1 < len2)
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return -1;
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if (len1 > len2)
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return 1;
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/* Compare stages */
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flags1 &= CE_STAGEMASK;
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flags2 &= CE_STAGEMASK;
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if (flags1 < flags2)
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return -1;
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if (flags1 > flags2)
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return 1;
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return 0;
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}
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int cache_name_pos(const char *name, int namelen)
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{
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int first, last;
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first = 0;
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last = active_nr;
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while (last > first) {
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int next = (last + first) >> 1;
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struct cache_entry *ce = active_cache[next];
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int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
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if (!cmp)
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return next;
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if (cmp < 0) {
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last = next;
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continue;
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}
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first = next+1;
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}
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return -first-1;
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}
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/* Remove entry, return true if there are more entries to go.. */
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int remove_cache_entry_at(int pos)
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{
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active_cache_changed = 1;
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active_nr--;
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if (pos >= active_nr)
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return 0;
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memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
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return 1;
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}
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int remove_file_from_cache(const char *path)
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{
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int pos = cache_name_pos(path, strlen(path));
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if (pos < 0)
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pos = -pos-1;
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while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
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remove_cache_entry_at(pos);
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return 0;
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}
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int add_file_to_cache(const char *path, int verbose)
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{
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int size, namelen;
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struct stat st;
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struct cache_entry *ce;
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if (lstat(path, &st))
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die("%s: unable to stat (%s)", path, strerror(errno));
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if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode))
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die("%s: can only add regular files or symbolic links", path);
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namelen = strlen(path);
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size = cache_entry_size(namelen);
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ce = xcalloc(1, size);
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memcpy(ce->name, path, namelen);
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ce->ce_flags = htons(namelen);
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fill_stat_cache_info(ce, &st);
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if (trust_executable_bit && has_symlinks)
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ce->ce_mode = create_ce_mode(st.st_mode);
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else {
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/* If there is an existing entry, pick the mode bits and type
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* from it, otherwise assume unexecutable regular file.
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*/
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struct cache_entry *ent;
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int pos = cache_name_pos(path, namelen);
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ent = (0 <= pos) ? active_cache[pos] : NULL;
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ce->ce_mode = ce_mode_from_stat(ent, st.st_mode);
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}
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if (index_path(ce->sha1, path, &st, 1))
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die("unable to index file %s", path);
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if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
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die("unable to add %s to index",path);
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if (verbose)
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printf("add '%s'\n", path);
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cache_tree_invalidate_path(active_cache_tree, path);
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return 0;
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}
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int ce_same_name(struct cache_entry *a, struct cache_entry *b)
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{
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int len = ce_namelen(a);
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return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
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}
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int ce_path_match(const struct cache_entry *ce, const char **pathspec)
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{
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const char *match, *name;
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int len;
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if (!pathspec)
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return 1;
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len = ce_namelen(ce);
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name = ce->name;
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while ((match = *pathspec++) != NULL) {
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int matchlen = strlen(match);
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if (matchlen > len)
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continue;
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if (memcmp(name, match, matchlen))
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continue;
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if (matchlen && name[matchlen-1] == '/')
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return 1;
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if (name[matchlen] == '/' || !name[matchlen])
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return 1;
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if (!matchlen)
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return 1;
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}
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return 0;
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}
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/*
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* We fundamentally don't like some paths: we don't want
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* dot or dot-dot anywhere, and for obvious reasons don't
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* want to recurse into ".git" either.
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*
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* Also, we don't want double slashes or slashes at the
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* end that can make pathnames ambiguous.
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*/
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static int verify_dotfile(const char *rest)
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{
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/*
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* The first character was '.', but that
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* has already been discarded, we now test
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* the rest.
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*/
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switch (*rest) {
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/* "." is not allowed */
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case '\0': case '/':
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return 0;
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/*
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* ".git" followed by NUL or slash is bad. This
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* shares the path end test with the ".." case.
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*/
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case 'g':
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if (rest[1] != 'i')
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break;
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if (rest[2] != 't')
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break;
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rest += 2;
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/* fallthrough */
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case '.':
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if (rest[1] == '\0' || rest[1] == '/')
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return 0;
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}
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return 1;
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}
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int verify_path(const char *path)
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{
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char c;
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goto inside;
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for (;;) {
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if (!c)
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return 1;
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if (c == '/') {
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inside:
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c = *path++;
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switch (c) {
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default:
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continue;
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case '/': case '\0':
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break;
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case '.':
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if (verify_dotfile(path))
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continue;
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}
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return 0;
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}
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c = *path++;
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}
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}
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/*
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* Do we have another file that has the beginning components being a
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* proper superset of the name we're trying to add?
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*/
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static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
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{
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int retval = 0;
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int len = ce_namelen(ce);
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int stage = ce_stage(ce);
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const char *name = ce->name;
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while (pos < active_nr) {
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struct cache_entry *p = active_cache[pos++];
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if (len >= ce_namelen(p))
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break;
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if (memcmp(name, p->name, len))
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break;
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if (ce_stage(p) != stage)
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continue;
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if (p->name[len] != '/')
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continue;
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if (!ce_stage(p) && !p->ce_mode)
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continue;
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retval = -1;
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if (!ok_to_replace)
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break;
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remove_cache_entry_at(--pos);
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}
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return retval;
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}
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|
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/*
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* Do we have another file with a pathname that is a proper
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* subset of the name we're trying to add?
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*/
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static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
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{
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int retval = 0;
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int stage = ce_stage(ce);
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const char *name = ce->name;
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const char *slash = name + ce_namelen(ce);
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for (;;) {
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int len;
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for (;;) {
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if (*--slash == '/')
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break;
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if (slash <= ce->name)
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return retval;
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}
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len = slash - name;
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pos = cache_name_pos(name, ntohs(create_ce_flags(len, stage)));
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if (pos >= 0) {
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/*
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* Found one, but not so fast. This could
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* be a marker that says "I was here, but
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* I am being removed". Such an entry is
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* not a part of the resulting tree, and
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* it is Ok to have a directory at the same
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* path.
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*/
|
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if (stage || active_cache[pos]->ce_mode) {
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retval = -1;
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if (!ok_to_replace)
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break;
|
|
remove_cache_entry_at(pos);
|
|
continue;
|
|
}
|
|
}
|
|
else
|
|
pos = -pos-1;
|
|
|
|
/*
|
|
* Trivial optimization: if we find an entry that
|
|
* already matches the sub-directory, then we know
|
|
* we're ok, and we can exit.
|
|
*/
|
|
while (pos < active_nr) {
|
|
struct cache_entry *p = active_cache[pos];
|
|
if ((ce_namelen(p) <= len) ||
|
|
(p->name[len] != '/') ||
|
|
memcmp(p->name, name, len))
|
|
break; /* not our subdirectory */
|
|
if (ce_stage(p) == stage && (stage || p->ce_mode))
|
|
/* p is at the same stage as our entry, and
|
|
* is a subdirectory of what we are looking
|
|
* at, so we cannot have conflicts at our
|
|
* level or anything shorter.
|
|
*/
|
|
return retval;
|
|
pos++;
|
|
}
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/* We may be in a situation where we already have path/file and path
|
|
* is being added, or we already have path and path/file is being
|
|
* added. Either one would result in a nonsense tree that has path
|
|
* twice when git-write-tree tries to write it out. Prevent it.
|
|
*
|
|
* If ok-to-replace is specified, we remove the conflicting entries
|
|
* from the cache so the caller should recompute the insert position.
|
|
* When this happens, we return non-zero.
|
|
*/
|
|
static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
|
|
{
|
|
int retval;
|
|
|
|
/*
|
|
* When ce is an "I am going away" entry, we allow it to be added
|
|
*/
|
|
if (!ce_stage(ce) && !ce->ce_mode)
|
|
return 0;
|
|
|
|
/*
|
|
* We check if the path is a sub-path of a subsequent pathname
|
|
* first, since removing those will not change the position
|
|
* in the array.
|
|
*/
|
|
retval = has_file_name(ce, pos, ok_to_replace);
|
|
|
|
/*
|
|
* Then check if the path might have a clashing sub-directory
|
|
* before it.
|
|
*/
|
|
return retval + has_dir_name(ce, pos, ok_to_replace);
|
|
}
|
|
|
|
int add_cache_entry(struct cache_entry *ce, int option)
|
|
{
|
|
int pos;
|
|
int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
|
|
int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
|
|
int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
|
|
|
|
pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
|
|
|
|
/* existing match? Just replace it. */
|
|
if (pos >= 0) {
|
|
active_cache_changed = 1;
|
|
active_cache[pos] = ce;
|
|
return 0;
|
|
}
|
|
pos = -pos-1;
|
|
|
|
/*
|
|
* Inserting a merged entry ("stage 0") into the index
|
|
* will always replace all non-merged entries..
|
|
*/
|
|
if (pos < active_nr && ce_stage(ce) == 0) {
|
|
while (ce_same_name(active_cache[pos], ce)) {
|
|
ok_to_add = 1;
|
|
if (!remove_cache_entry_at(pos))
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!ok_to_add)
|
|
return -1;
|
|
if (!verify_path(ce->name))
|
|
return -1;
|
|
|
|
if (!skip_df_check &&
|
|
check_file_directory_conflict(ce, pos, ok_to_replace)) {
|
|
if (!ok_to_replace)
|
|
return error("'%s' appears as both a file and as a directory", ce->name);
|
|
pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
|
|
pos = -pos-1;
|
|
}
|
|
|
|
/* Make sure the array is big enough .. */
|
|
if (active_nr == active_alloc) {
|
|
active_alloc = alloc_nr(active_alloc);
|
|
active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
|
|
}
|
|
|
|
/* Add it in.. */
|
|
active_nr++;
|
|
if (active_nr > pos)
|
|
memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
|
|
active_cache[pos] = ce;
|
|
active_cache_changed = 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* "refresh" does not calculate a new sha1 file or bring the
|
|
* cache up-to-date for mode/content changes. But what it
|
|
* _does_ do is to "re-match" the stat information of a file
|
|
* with the cache, so that you can refresh the cache for a
|
|
* file that hasn't been changed but where the stat entry is
|
|
* out of date.
|
|
*
|
|
* For example, you'd want to do this after doing a "git-read-tree",
|
|
* to link up the stat cache details with the proper files.
|
|
*/
|
|
static struct cache_entry *refresh_cache_ent(struct cache_entry *ce, int really, int *err)
|
|
{
|
|
struct stat st;
|
|
struct cache_entry *updated;
|
|
int changed, size;
|
|
|
|
if (lstat(ce->name, &st) < 0) {
|
|
if (err)
|
|
*err = errno;
|
|
return NULL;
|
|
}
|
|
|
|
changed = ce_match_stat(ce, &st, really);
|
|
if (!changed) {
|
|
if (really && assume_unchanged &&
|
|
!(ce->ce_flags & htons(CE_VALID)))
|
|
; /* mark this one VALID again */
|
|
else
|
|
return ce;
|
|
}
|
|
|
|
if (ce_modified(ce, &st, really)) {
|
|
if (err)
|
|
*err = EINVAL;
|
|
return NULL;
|
|
}
|
|
|
|
size = ce_size(ce);
|
|
updated = xmalloc(size);
|
|
memcpy(updated, ce, size);
|
|
fill_stat_cache_info(updated, &st);
|
|
|
|
/* In this case, if really is not set, we should leave
|
|
* CE_VALID bit alone. Otherwise, paths marked with
|
|
* --no-assume-unchanged (i.e. things to be edited) will
|
|
* reacquire CE_VALID bit automatically, which is not
|
|
* really what we want.
|
|
*/
|
|
if (!really && assume_unchanged && !(ce->ce_flags & htons(CE_VALID)))
|
|
updated->ce_flags &= ~htons(CE_VALID);
|
|
|
|
return updated;
|
|
}
|
|
|
|
int refresh_cache(unsigned int flags)
|
|
{
|
|
int i;
|
|
int has_errors = 0;
|
|
int really = (flags & REFRESH_REALLY) != 0;
|
|
int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
|
|
int quiet = (flags & REFRESH_QUIET) != 0;
|
|
int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
|
|
|
|
for (i = 0; i < active_nr; i++) {
|
|
struct cache_entry *ce, *new;
|
|
int cache_errno = 0;
|
|
|
|
ce = active_cache[i];
|
|
if (ce_stage(ce)) {
|
|
while ((i < active_nr) &&
|
|
! strcmp(active_cache[i]->name, ce->name))
|
|
i++;
|
|
i--;
|
|
if (allow_unmerged)
|
|
continue;
|
|
printf("%s: needs merge\n", ce->name);
|
|
has_errors = 1;
|
|
continue;
|
|
}
|
|
|
|
new = refresh_cache_ent(ce, really, &cache_errno);
|
|
if (new == ce)
|
|
continue;
|
|
if (!new) {
|
|
if (not_new && cache_errno == ENOENT)
|
|
continue;
|
|
if (really && cache_errno == EINVAL) {
|
|
/* If we are doing --really-refresh that
|
|
* means the index is not valid anymore.
|
|
*/
|
|
ce->ce_flags &= ~htons(CE_VALID);
|
|
active_cache_changed = 1;
|
|
}
|
|
if (quiet)
|
|
continue;
|
|
printf("%s: needs update\n", ce->name);
|
|
has_errors = 1;
|
|
continue;
|
|
}
|
|
active_cache_changed = 1;
|
|
/* You can NOT just free active_cache[i] here, since it
|
|
* might not be necessarily malloc()ed but can also come
|
|
* from mmap(). */
|
|
active_cache[i] = new;
|
|
}
|
|
return has_errors;
|
|
}
|
|
|
|
struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
|
|
{
|
|
return refresh_cache_ent(ce, really, NULL);
|
|
}
|
|
|
|
static int verify_hdr(struct cache_header *hdr, unsigned long size)
|
|
{
|
|
SHA_CTX c;
|
|
unsigned char sha1[20];
|
|
|
|
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
|
|
return error("bad signature");
|
|
if (hdr->hdr_version != htonl(2))
|
|
return error("bad index version");
|
|
SHA1_Init(&c);
|
|
SHA1_Update(&c, hdr, size - 20);
|
|
SHA1_Final(sha1, &c);
|
|
if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
|
|
return error("bad index file sha1 signature");
|
|
return 0;
|
|
}
|
|
|
|
static int read_index_extension(const char *ext, void *data, unsigned long sz)
|
|
{
|
|
switch (CACHE_EXT(ext)) {
|
|
case CACHE_EXT_TREE:
|
|
active_cache_tree = cache_tree_read(data, sz);
|
|
break;
|
|
default:
|
|
if (*ext < 'A' || 'Z' < *ext)
|
|
return error("index uses %.4s extension, which we do not understand",
|
|
ext);
|
|
fprintf(stderr, "ignoring %.4s extension\n", ext);
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int read_cache(void)
|
|
{
|
|
return read_cache_from(get_index_file());
|
|
}
|
|
|
|
/* remember to discard_cache() before reading a different cache! */
|
|
int read_cache_from(const char *path)
|
|
{
|
|
int fd, i;
|
|
struct stat st;
|
|
unsigned long offset;
|
|
struct cache_header *hdr;
|
|
|
|
errno = EBUSY;
|
|
if (cache_mmap)
|
|
return active_nr;
|
|
|
|
errno = ENOENT;
|
|
index_file_timestamp = 0;
|
|
fd = open(path, O_RDONLY);
|
|
if (fd < 0) {
|
|
if (errno == ENOENT)
|
|
return 0;
|
|
die("index file open failed (%s)", strerror(errno));
|
|
}
|
|
|
|
if (!fstat(fd, &st)) {
|
|
cache_mmap_size = xsize_t(st.st_size);
|
|
errno = EINVAL;
|
|
if (cache_mmap_size >= sizeof(struct cache_header) + 20)
|
|
cache_mmap = xmmap(NULL, cache_mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
|
|
else
|
|
die("index file smaller than expected");
|
|
} else
|
|
die("cannot stat the open index (%s)", strerror(errno));
|
|
close(fd);
|
|
|
|
hdr = cache_mmap;
|
|
if (verify_hdr(hdr, cache_mmap_size) < 0)
|
|
goto unmap;
|
|
|
|
active_nr = ntohl(hdr->hdr_entries);
|
|
active_alloc = alloc_nr(active_nr);
|
|
active_cache = xcalloc(active_alloc, sizeof(struct cache_entry *));
|
|
|
|
offset = sizeof(*hdr);
|
|
for (i = 0; i < active_nr; i++) {
|
|
struct cache_entry *ce = (struct cache_entry *) ((char *) cache_mmap + offset);
|
|
offset = offset + ce_size(ce);
|
|
active_cache[i] = ce;
|
|
}
|
|
index_file_timestamp = st.st_mtime;
|
|
while (offset <= cache_mmap_size - 20 - 8) {
|
|
/* After an array of active_nr index entries,
|
|
* there can be arbitrary number of extended
|
|
* sections, each of which is prefixed with
|
|
* extension name (4-byte) and section length
|
|
* in 4-byte network byte order.
|
|
*/
|
|
unsigned long extsize;
|
|
memcpy(&extsize, (char *) cache_mmap + offset + 4, 4);
|
|
extsize = ntohl(extsize);
|
|
if (read_index_extension(((const char *) cache_mmap) + offset,
|
|
(char *) cache_mmap + offset + 8,
|
|
extsize) < 0)
|
|
goto unmap;
|
|
offset += 8;
|
|
offset += extsize;
|
|
}
|
|
return active_nr;
|
|
|
|
unmap:
|
|
munmap(cache_mmap, cache_mmap_size);
|
|
errno = EINVAL;
|
|
die("index file corrupt");
|
|
}
|
|
|
|
int discard_cache(void)
|
|
{
|
|
int ret;
|
|
|
|
active_nr = active_cache_changed = 0;
|
|
index_file_timestamp = 0;
|
|
cache_tree_free(&active_cache_tree);
|
|
if (cache_mmap == NULL)
|
|
return 0;
|
|
ret = munmap(cache_mmap, cache_mmap_size);
|
|
cache_mmap = NULL;
|
|
cache_mmap_size = 0;
|
|
|
|
/* no need to throw away allocated active_cache */
|
|
return ret;
|
|
}
|
|
|
|
#define WRITE_BUFFER_SIZE 8192
|
|
static unsigned char write_buffer[WRITE_BUFFER_SIZE];
|
|
static unsigned long write_buffer_len;
|
|
|
|
static int ce_write_flush(SHA_CTX *context, int fd)
|
|
{
|
|
unsigned int buffered = write_buffer_len;
|
|
if (buffered) {
|
|
SHA1_Update(context, write_buffer, buffered);
|
|
if (write_in_full(fd, write_buffer, buffered) != buffered)
|
|
return -1;
|
|
write_buffer_len = 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
|
|
{
|
|
while (len) {
|
|
unsigned int buffered = write_buffer_len;
|
|
unsigned int partial = WRITE_BUFFER_SIZE - buffered;
|
|
if (partial > len)
|
|
partial = len;
|
|
memcpy(write_buffer + buffered, data, partial);
|
|
buffered += partial;
|
|
if (buffered == WRITE_BUFFER_SIZE) {
|
|
write_buffer_len = buffered;
|
|
if (ce_write_flush(context, fd))
|
|
return -1;
|
|
buffered = 0;
|
|
}
|
|
write_buffer_len = buffered;
|
|
len -= partial;
|
|
data = (char *) data + partial;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int write_index_ext_header(SHA_CTX *context, int fd,
|
|
unsigned int ext, unsigned int sz)
|
|
{
|
|
ext = htonl(ext);
|
|
sz = htonl(sz);
|
|
return ((ce_write(context, fd, &ext, 4) < 0) ||
|
|
(ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
|
|
}
|
|
|
|
static int ce_flush(SHA_CTX *context, int fd)
|
|
{
|
|
unsigned int left = write_buffer_len;
|
|
|
|
if (left) {
|
|
write_buffer_len = 0;
|
|
SHA1_Update(context, write_buffer, left);
|
|
}
|
|
|
|
/* Flush first if not enough space for SHA1 signature */
|
|
if (left + 20 > WRITE_BUFFER_SIZE) {
|
|
if (write_in_full(fd, write_buffer, left) != left)
|
|
return -1;
|
|
left = 0;
|
|
}
|
|
|
|
/* Append the SHA1 signature at the end */
|
|
SHA1_Final(write_buffer + left, context);
|
|
left += 20;
|
|
return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
|
|
}
|
|
|
|
static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
|
|
{
|
|
/*
|
|
* The only thing we care about in this function is to smudge the
|
|
* falsely clean entry due to touch-update-touch race, so we leave
|
|
* everything else as they are. We are called for entries whose
|
|
* ce_mtime match the index file mtime.
|
|
*/
|
|
struct stat st;
|
|
|
|
if (lstat(ce->name, &st) < 0)
|
|
return;
|
|
if (ce_match_stat_basic(ce, &st))
|
|
return;
|
|
if (ce_modified_check_fs(ce, &st)) {
|
|
/* This is "racily clean"; smudge it. Note that this
|
|
* is a tricky code. At first glance, it may appear
|
|
* that it can break with this sequence:
|
|
*
|
|
* $ echo xyzzy >frotz
|
|
* $ git-update-index --add frotz
|
|
* $ : >frotz
|
|
* $ sleep 3
|
|
* $ echo filfre >nitfol
|
|
* $ git-update-index --add nitfol
|
|
*
|
|
* but it does not. When the second update-index runs,
|
|
* it notices that the entry "frotz" has the same timestamp
|
|
* as index, and if we were to smudge it by resetting its
|
|
* size to zero here, then the object name recorded
|
|
* in index is the 6-byte file but the cached stat information
|
|
* becomes zero --- which would then match what we would
|
|
* obtain from the filesystem next time we stat("frotz").
|
|
*
|
|
* However, the second update-index, before calling
|
|
* this function, notices that the cached size is 6
|
|
* bytes and what is on the filesystem is an empty
|
|
* file, and never calls us, so the cached size information
|
|
* for "frotz" stays 6 which does not match the filesystem.
|
|
*/
|
|
ce->ce_size = htonl(0);
|
|
}
|
|
}
|
|
|
|
int write_cache(int newfd, struct cache_entry **cache, int entries)
|
|
{
|
|
SHA_CTX c;
|
|
struct cache_header hdr;
|
|
int i, removed;
|
|
|
|
for (i = removed = 0; i < entries; i++)
|
|
if (!cache[i]->ce_mode)
|
|
removed++;
|
|
|
|
hdr.hdr_signature = htonl(CACHE_SIGNATURE);
|
|
hdr.hdr_version = htonl(2);
|
|
hdr.hdr_entries = htonl(entries - removed);
|
|
|
|
SHA1_Init(&c);
|
|
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
|
|
return -1;
|
|
|
|
for (i = 0; i < entries; i++) {
|
|
struct cache_entry *ce = cache[i];
|
|
if (!ce->ce_mode)
|
|
continue;
|
|
if (index_file_timestamp &&
|
|
index_file_timestamp <= ntohl(ce->ce_mtime.sec))
|
|
ce_smudge_racily_clean_entry(ce);
|
|
if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
|
|
return -1;
|
|
}
|
|
|
|
/* Write extension data here */
|
|
if (active_cache_tree) {
|
|
unsigned long sz;
|
|
void *data = cache_tree_write(active_cache_tree, &sz);
|
|
if (data &&
|
|
!write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sz) &&
|
|
!ce_write(&c, newfd, data, sz))
|
|
free(data);
|
|
else {
|
|
free(data);
|
|
return -1;
|
|
}
|
|
}
|
|
return ce_flush(&c, newfd);
|
|
}
|