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![Junio C Hamano](/assets/img/avatar_default.png)
This adds "assume unchanged" logic, started by this message in the list discussion recently: <Pine.LNX.4.64.0601311807470.7301@g5.osdl.org> This is a workaround for filesystems that do not have lstat() that is quick enough for the index mechanism to take advantage of. On the paths marked as "assumed to be unchanged", the user needs to explicitly use update-index to register the object name to be in the next commit. You can use two new options to update-index to set and reset the CE_VALID bit: git-update-index --assume-unchanged path... git-update-index --no-assume-unchanged path... These forms manipulate only the CE_VALID bit; it does not change the object name recorded in the index file. Nor they add a new entry to the index. When the configuration variable "core.ignorestat = true" is set, the index entries are marked with CE_VALID bit automatically after: - update-index to explicitly register the current object name to the index file. - when update-index --refresh finds the path to be up-to-date. - when tools like read-tree -u and apply --index update the working tree file and register the current object name to the index file. The flag is dropped upon read-tree that does not check out the index entry. This happens regardless of the core.ignorestat settings. Index entries marked with CE_VALID bit are assumed to be unchanged most of the time. However, there are cases that CE_VALID bit is ignored for the sake of safety and usability: - while "git-read-tree -m" or git-apply need to make sure that the paths involved in the merge do not have local modifications. This sacrifices performance for safety. - when git-checkout-index -f -q -u -a tries to see if it needs to checkout the paths. Otherwise you can never check anything out ;-). - when git-update-index --really-refresh (a new flag) tries to see if the index entry is up to date. You can start with everything marked as CE_VALID and run this once to drop CE_VALID bit for paths that are modified. Most notably, "update-index --refresh" honours CE_VALID and does not actively stat, so after you modified a file in the working tree, update-index --refresh would not notice until you tell the index about it with "git-update-index path" or "git-update-index --no-assume-unchanged path". This version is not expected to be perfect. I think diff between index and/or tree and working files may need some adjustment, and there probably needs other cases we should automatically unmark paths that are marked to be CE_VALID. But the basics seem to work, and ready to be tested by people who asked for this feature. Signed-off-by: Junio C Hamano <junkio@cox.net>
256 lines
5.7 KiB
C
256 lines
5.7 KiB
C
#include "cache.h"
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#include "tree.h"
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#include "diff.h"
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static int cached_only = 0;
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static int match_nonexisting = 0;
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static struct diff_options diff_options;
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/* A file entry went away or appeared */
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static void show_file(const char *prefix,
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struct cache_entry *ce,
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unsigned char *sha1, unsigned int mode)
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{
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diff_addremove(&diff_options, prefix[0], ntohl(mode),
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sha1, ce->name, NULL);
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}
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static int get_stat_data(struct cache_entry *ce,
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unsigned char ** sha1p, unsigned int *modep)
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{
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unsigned char *sha1 = ce->sha1;
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unsigned int mode = ce->ce_mode;
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if (!cached_only) {
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static unsigned char no_sha1[20];
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int changed;
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struct stat st;
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if (lstat(ce->name, &st) < 0) {
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if (errno == ENOENT && match_nonexisting) {
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*sha1p = sha1;
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*modep = mode;
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return 0;
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}
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return -1;
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}
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changed = ce_match_stat(ce, &st, 0);
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if (changed) {
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mode = create_ce_mode(st.st_mode);
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if (!trust_executable_bit &&
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S_ISREG(mode) && S_ISREG(ce->ce_mode) &&
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((mode ^ ce->ce_mode) == 0111))
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mode = ce->ce_mode;
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sha1 = no_sha1;
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}
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}
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*sha1p = sha1;
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*modep = mode;
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return 0;
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}
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static void show_new_file(struct cache_entry *new)
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{
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unsigned char *sha1;
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unsigned int mode;
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/* New file in the index: it might actually be different in
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* the working copy.
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*/
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if (get_stat_data(new, &sha1, &mode) < 0)
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return;
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show_file("+", new, sha1, mode);
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}
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static int show_modified(struct cache_entry *old,
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struct cache_entry *new,
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int report_missing)
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{
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unsigned int mode, oldmode;
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unsigned char *sha1;
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if (get_stat_data(new, &sha1, &mode) < 0) {
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if (report_missing)
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show_file("-", old, old->sha1, old->ce_mode);
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return -1;
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}
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oldmode = old->ce_mode;
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if (mode == oldmode && !memcmp(sha1, old->sha1, 20) &&
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!diff_options.find_copies_harder)
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return 0;
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mode = ntohl(mode);
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oldmode = ntohl(oldmode);
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diff_change(&diff_options, oldmode, mode,
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old->sha1, sha1, old->name, NULL);
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return 0;
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}
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static int diff_cache(struct cache_entry **ac, int entries, const char **pathspec)
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{
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while (entries) {
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struct cache_entry *ce = *ac;
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int same = (entries > 1) && ce_same_name(ce, ac[1]);
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if (!ce_path_match(ce, pathspec))
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goto skip_entry;
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switch (ce_stage(ce)) {
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case 0:
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/* No stage 1 entry? That means it's a new file */
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if (!same) {
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show_new_file(ce);
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break;
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}
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/* Show difference between old and new */
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show_modified(ac[1], ce, 1);
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break;
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case 1:
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/* No stage 3 (merge) entry? That means it's been deleted */
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if (!same) {
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show_file("-", ce, ce->sha1, ce->ce_mode);
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break;
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}
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/* We come here with ce pointing at stage 1
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* (original tree) and ac[1] pointing at stage
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* 3 (unmerged). show-modified with
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* report-missing set to false does not say the
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* file is deleted but reports true if work
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* tree does not have it, in which case we
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* fall through to report the unmerged state.
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* Otherwise, we show the differences between
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* the original tree and the work tree.
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*/
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if (!cached_only && !show_modified(ce, ac[1], 0))
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break;
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/* fallthru */
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case 3:
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diff_unmerge(&diff_options, ce->name);
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break;
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default:
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die("impossible cache entry stage");
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}
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skip_entry:
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/*
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* Ignore all the different stages for this file,
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* we've handled the relevant cases now.
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*/
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do {
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ac++;
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entries--;
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} while (entries && ce_same_name(ce, ac[0]));
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}
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return 0;
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}
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/*
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* This turns all merge entries into "stage 3". That guarantees that
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* when we read in the new tree (into "stage 1"), we won't lose sight
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* of the fact that we had unmerged entries.
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*/
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static void mark_merge_entries(void)
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{
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int i;
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for (i = 0; i < active_nr; i++) {
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struct cache_entry *ce = active_cache[i];
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if (!ce_stage(ce))
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continue;
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ce->ce_flags |= htons(CE_STAGEMASK);
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}
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}
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static const char diff_cache_usage[] =
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"git-diff-index [-m] [--cached] "
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"[<common diff options>] <tree-ish> [<path>...]"
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COMMON_DIFF_OPTIONS_HELP;
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int main(int argc, const char **argv)
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{
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const char *tree_name = NULL;
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unsigned char sha1[20];
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const char *prefix = setup_git_directory();
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const char **pathspec = NULL;
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struct tree *tree;
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int ret;
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int allow_options = 1;
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int i;
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git_config(git_diff_config);
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diff_setup(&diff_options);
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for (i = 1; i < argc; i++) {
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const char *arg = argv[i];
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int diff_opt_cnt;
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if (!allow_options || *arg != '-') {
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if (tree_name)
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break;
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tree_name = arg;
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continue;
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}
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if (!strcmp(arg, "--")) {
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allow_options = 0;
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continue;
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}
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if (!strcmp(arg, "-r")) {
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/* We accept the -r flag just to look like git-diff-tree */
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continue;
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}
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if (!strcmp(arg, "--cc"))
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/*
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* I _think_ "diff-index --cached HEAD" with an
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* unmerged index could show something else
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* later, but pretend --cc is the same as -p for
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* now. "git diff" uses --cc by default.
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*/
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argv[i] = arg = "-p";
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diff_opt_cnt = diff_opt_parse(&diff_options, argv + i,
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argc - i);
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if (diff_opt_cnt < 0)
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usage(diff_cache_usage);
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else if (diff_opt_cnt) {
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i += diff_opt_cnt - 1;
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continue;
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}
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if (!strcmp(arg, "-m")) {
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match_nonexisting = 1;
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continue;
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}
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if (!strcmp(arg, "--cached")) {
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cached_only = 1;
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continue;
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}
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usage(diff_cache_usage);
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}
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pathspec = get_pathspec(prefix, argv + i);
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if (diff_setup_done(&diff_options) < 0)
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usage(diff_cache_usage);
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if (!tree_name || get_sha1(tree_name, sha1))
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usage(diff_cache_usage);
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read_cache();
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mark_merge_entries();
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tree = parse_tree_indirect(sha1);
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if (!tree)
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die("bad tree object %s", tree_name);
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if (read_tree(tree, 1, pathspec))
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die("unable to read tree object %s", tree_name);
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ret = diff_cache(active_cache, active_nr, pathspec);
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diffcore_std(&diff_options);
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diff_flush(&diff_options);
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return ret;
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}
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