mirror of
https://git.proxmox.com/git/libgit2
synced 2025-05-09 13:04:42 +00:00
filter: avoid races during filter registration
Previously we would set the global filter registry structure before adding filters to the structure, without a lock, which is quite racy. Now, register default filters during global registration and use an rwlock to read and write the filter registry (as appopriate).
This commit is contained in:
Edward Thomson
parent
6e0fc1a631
commit
2ed855a9e8
285
src/filter.c
285
src/filter.c
@ -56,80 +56,15 @@ static int filter_def_priority_cmp(const void *a, const void *b)
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return (pa < pb) ? -1 : (pa > pb) ? 1 : 0;
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}
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struct filter_registry {
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struct git_filter_registry {
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git_rwlock lock;
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git_vector filters;
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};
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static struct filter_registry *git__filter_registry = NULL;
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static struct git_filter_registry filter_registry;
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static void filter_registry_shutdown(void)
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{
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struct filter_registry *reg = NULL;
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size_t pos;
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git_filter_def *fdef;
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static void git_filter_global_shutdown(void);
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if ((reg = git__swap(git__filter_registry, NULL)) == NULL)
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return;
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git_vector_foreach(®->filters, pos, fdef) {
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if (fdef->filter && fdef->filter->shutdown) {
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fdef->filter->shutdown(fdef->filter);
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fdef->initialized = false;
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}
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git__free(fdef->filter_name);
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git__free(fdef->attrdata);
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git__free(fdef);
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}
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git_vector_free(®->filters);
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git__free(reg);
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}
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static int filter_registry_initialize(void)
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{
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int error = 0;
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struct filter_registry *reg;
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if (git__filter_registry)
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return 0;
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reg = git__calloc(1, sizeof(struct filter_registry));
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GITERR_CHECK_ALLOC(reg);
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if ((error = git_vector_init(
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®->filters, 2, filter_def_priority_cmp)) < 0)
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goto cleanup;
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reg = git__compare_and_swap(&git__filter_registry, NULL, reg);
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if (reg != NULL)
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goto cleanup;
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git__on_shutdown(filter_registry_shutdown);
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/* try to register both default filters */
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{
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git_filter *crlf = git_crlf_filter_new();
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git_filter *ident = git_ident_filter_new();
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if (crlf && git_filter_register(
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GIT_FILTER_CRLF, crlf, GIT_FILTER_CRLF_PRIORITY) < 0)
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crlf = NULL;
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if (ident && git_filter_register(
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GIT_FILTER_IDENT, ident, GIT_FILTER_IDENT_PRIORITY) < 0)
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ident = NULL;
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if (!crlf || !ident)
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return -1;
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}
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return 0;
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cleanup:
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git_vector_free(®->filters);
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git__free(reg);
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return error;
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}
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static int filter_def_scan_attrs(
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git_buf *attrs, size_t *nattr, size_t *nmatch, const char *attr_str)
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@ -210,40 +145,14 @@ static int filter_def_filter_key_check(const void *key, const void *fdef)
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return (key == filter) ? 0 : -1;
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}
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static int filter_registry_find(size_t *pos, const char *name)
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{
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return git_vector_search2(
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pos, &git__filter_registry->filters, filter_def_name_key_check, name);
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}
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static git_filter_def *filter_registry_lookup(size_t *pos, const char *name)
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{
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git_filter_def *fdef = NULL;
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if (!filter_registry_find(pos, name))
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fdef = git_vector_get(&git__filter_registry->filters, *pos);
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return fdef;
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}
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int git_filter_register(
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/* Note: callers must lock the registry before calling this function */
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static int filter_registry_insert(
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const char *name, git_filter *filter, int priority)
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{
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git_filter_def *fdef;
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size_t nattr = 0, nmatch = 0, alloc_len;
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git_buf attrs = GIT_BUF_INIT;
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assert(name && filter);
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if (filter_registry_initialize() < 0)
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return -1;
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if (!filter_registry_find(NULL, name)) {
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giterr_set(
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GITERR_FILTER, "Attempt to reregister existing filter '%s'", name);
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return GIT_EEXISTS;
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}
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if (filter_def_scan_attrs(&attrs, &nattr, &nmatch, filter->attributes) < 0)
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return -1;
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@ -265,21 +174,123 @@ int git_filter_register(
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filter_def_set_attrs(fdef);
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if (git_vector_insert(&git__filter_registry->filters, fdef) < 0) {
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if (git_vector_insert(&filter_registry.filters, fdef) < 0) {
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git__free(fdef->filter_name);
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git__free(fdef->attrdata);
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git__free(fdef);
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return -1;
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}
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git_vector_sort(&git__filter_registry->filters);
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git_vector_sort(&filter_registry.filters);
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return 0;
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}
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int git_filter_global_init(void)
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{
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git_filter *crlf = NULL, *ident = NULL;
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int error = 0;
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if (git_rwlock_init(&filter_registry.lock) < 0)
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return -1;
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if ((error = git_vector_init(&filter_registry.filters, 2,
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filter_def_priority_cmp)) < 0)
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goto done;
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if ((crlf = git_crlf_filter_new()) == NULL ||
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filter_registry_insert(
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GIT_FILTER_CRLF, crlf, GIT_FILTER_CRLF_PRIORITY) < 0 ||
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(ident = git_ident_filter_new()) == NULL ||
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filter_registry_insert(
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GIT_FILTER_IDENT, ident, GIT_FILTER_IDENT_PRIORITY) < 0)
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error = -1;
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git__on_shutdown(git_filter_global_shutdown);
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done:
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if (error) {
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git_filter_free(crlf);
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git_filter_free(ident);
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}
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return error;
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}
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static void git_filter_global_shutdown(void)
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{
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size_t pos;
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git_filter_def *fdef;
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if (git_rwlock_wrlock(&filter_registry.lock) < 0)
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return;
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git_vector_foreach(&filter_registry.filters, pos, fdef) {
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if (fdef->filter && fdef->filter->shutdown) {
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fdef->filter->shutdown(fdef->filter);
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fdef->initialized = false;
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}
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git__free(fdef->filter_name);
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git__free(fdef->attrdata);
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git__free(fdef);
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}
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git_vector_free(&filter_registry.filters);
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git_rwlock_wrunlock(&filter_registry.lock);
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git_rwlock_free(&filter_registry.lock);
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}
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/* Note: callers must lock the registry before calling this function */
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static int filter_registry_find(size_t *pos, const char *name)
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{
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return git_vector_search2(
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pos, &filter_registry.filters, filter_def_name_key_check, name);
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}
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/* Note: callers must lock the registry before calling this function */
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static git_filter_def *filter_registry_lookup(size_t *pos, const char *name)
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{
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git_filter_def *fdef = NULL;
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if (!filter_registry_find(pos, name))
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fdef = git_vector_get(&filter_registry.filters, *pos);
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return fdef;
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}
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int git_filter_register(
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const char *name, git_filter *filter, int priority)
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{
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int error;
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assert(name && filter);
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if (git_rwlock_wrlock(&filter_registry.lock) < 0) {
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giterr_set(GITERR_OS, "failed to lock filter registry");
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return -1;
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}
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if (!filter_registry_find(NULL, name)) {
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giterr_set(
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GITERR_FILTER, "attempt to reregister existing filter '%s'", name);
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error = GIT_EEXISTS;
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goto done;
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}
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error = filter_registry_insert(name, filter, priority);
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done:
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git_rwlock_wrunlock(&filter_registry.lock);
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return error;
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}
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int git_filter_unregister(const char *name)
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{
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size_t pos;
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git_filter_def *fdef;
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int error = 0;
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assert(name);
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@ -289,12 +300,18 @@ int git_filter_unregister(const char *name)
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return -1;
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}
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if ((fdef = filter_registry_lookup(&pos, name)) == NULL) {
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giterr_set(GITERR_FILTER, "Cannot find filter '%s' to unregister", name);
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return GIT_ENOTFOUND;
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if (git_rwlock_wrlock(&filter_registry.lock) < 0) {
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giterr_set(GITERR_OS, "failed to lock filter registry");
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return -1;
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}
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(void)git_vector_remove(&git__filter_registry->filters, pos);
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if ((fdef = filter_registry_lookup(&pos, name)) == NULL) {
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giterr_set(GITERR_FILTER, "Cannot find filter '%s' to unregister", name);
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error = GIT_ENOTFOUND;
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goto done;
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}
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git_vector_remove(&filter_registry.filters, pos);
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if (fdef->initialized && fdef->filter && fdef->filter->shutdown) {
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fdef->filter->shutdown(fdef->filter);
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@ -305,21 +322,18 @@ int git_filter_unregister(const char *name)
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git__free(fdef->attrdata);
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git__free(fdef);
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return 0;
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done:
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git_rwlock_wrunlock(&filter_registry.lock);
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return error;
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}
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static int filter_initialize(git_filter_def *fdef)
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{
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int error = 0;
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if (!fdef->initialized &&
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fdef->filter &&
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fdef->filter->initialize &&
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(error = fdef->filter->initialize(fdef->filter)) < 0)
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{
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/* auto-unregister if initialize fails */
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git_filter_unregister(fdef->filter_name);
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return error;
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if (!fdef->initialized && fdef->filter && fdef->filter->initialize) {
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if ((error = fdef->filter->initialize(fdef->filter)) < 0)
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return error;
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}
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fdef->initialized = true;
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@ -330,17 +344,22 @@ git_filter *git_filter_lookup(const char *name)
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{
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size_t pos;
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git_filter_def *fdef;
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git_filter *filter = NULL;
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if (filter_registry_initialize() < 0)
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if (git_rwlock_rdlock(&filter_registry.lock) < 0) {
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giterr_set(GITERR_OS, "failed to lock filter registry");
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return NULL;
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}
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if ((fdef = filter_registry_lookup(&pos, name)) == NULL)
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return NULL;
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if ((fdef = filter_registry_lookup(&pos, name)) == NULL ||
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(!fdef->initialized && filter_initialize(fdef) < 0))
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goto done;
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if (!fdef->initialized && filter_initialize(fdef) < 0)
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return NULL;
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filter = fdef->filter;
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return fdef->filter;
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done:
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git_rwlock_rdunlock(&filter_registry.lock);
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return filter;
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}
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void git_filter_free(git_filter *filter)
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@ -478,8 +497,10 @@ int git_filter_list__load_ext(
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size_t idx;
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git_filter_def *fdef;
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if (filter_registry_initialize() < 0)
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if (git_rwlock_rdlock(&filter_registry.lock) < 0) {
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giterr_set(GITERR_OS, "failed to lock filter registry");
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return -1;
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}
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src.repo = repo;
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src.path = path;
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@ -489,7 +510,7 @@ int git_filter_list__load_ext(
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if (blob)
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git_oid_cpy(&src.oid, git_blob_id(blob));
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git_vector_foreach(&git__filter_registry->filters, idx, fdef) {
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git_vector_foreach(&filter_registry.filters, idx, fdef) {
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const char **values = NULL;
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void *payload = NULL;
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@ -523,7 +544,7 @@ int git_filter_list__load_ext(
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else {
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if (!fl) {
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if ((error = filter_list_new(&fl, &src)) < 0)
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return error;
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break;
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fl->temp_buf = filter_opts->temp_buf;
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}
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@ -537,6 +558,8 @@ int git_filter_list__load_ext(
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}
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}
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git_rwlock_rdunlock(&filter_registry.lock);
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if (error && fl != NULL) {
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git_array_clear(fl->filters);
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git__free(fl);
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@ -604,19 +627,27 @@ int git_filter_list_push(
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{
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int error = 0;
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size_t pos;
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git_filter_def *fdef;
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git_filter_def *fdef = NULL;
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git_filter_entry *fe;
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assert(fl && filter);
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if (git_vector_search2(
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&pos, &git__filter_registry->filters,
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filter_def_filter_key_check, filter) < 0) {
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giterr_set(GITERR_FILTER, "Cannot use an unregistered filter");
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if (git_rwlock_rdlock(&filter_registry.lock) < 0) {
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giterr_set(GITERR_OS, "failed to lock filter registry");
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return -1;
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}
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fdef = git_vector_get(&git__filter_registry->filters, pos);
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if (git_vector_search2(
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&pos, &filter_registry.filters,
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filter_def_filter_key_check, filter) == 0)
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fdef = git_vector_get(&filter_registry.filters, pos);
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git_rwlock_rdunlock(&filter_registry.lock);
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if (fdef == NULL) {
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giterr_set(GITERR_FILTER, "Cannot use an unregistered filter");
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return -1;
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}
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if (!fdef->initialized && (error = filter_initialize(fdef)) < 0)
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return error;
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@ -32,6 +32,8 @@ typedef struct {
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#define GIT_FILTER_OPTIONS_INIT {0}
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extern int git_filter_global_init(void);
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extern void git_filter_free(git_filter *filter);
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extern int git_filter_list__load_ext(
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