1 files changed, 624 insertions, 42 deletions

diff --git a/src/filter.c b/src/filter.c
index 9f749dcbd..9f866fe88 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -10,68 +10,594 @@
 #include "hash.h"
 #include "filter.h"
 #include "repository.h"
+#include "global.h"
+#include "git2/sys/filter.h"
 #include "git2/config.h"
 #include "blob.h"
+#include "attr_file.h"
+#include "array.h"
 
-int git_filters_load(git_vector *filters, git_repository *repo, const char *path, int mode)
+struct git_filter_source {
+	git_repository *repo;
+	const char     *path;
+	git_oid         oid;  /* zero if unknown (which is likely) */
+	uint16_t        filemode; /* zero if unknown */
+	git_filter_mode_t mode;
+};
+
+typedef struct {
+	git_filter *filter;
+	void *payload;
+} git_filter_entry;
+
+struct git_filter_list {
+	git_array_t(git_filter_entry) filters;
+	git_filter_source source;
+	char path[GIT_FLEX_ARRAY];
+};
+
+typedef struct {
+	const char *filter_name;
+	git_filter *filter;
+	int priority;
+	int initialized;
+	size_t nattrs, nmatches;
+	char *attrdata;
+	const char *attrs[GIT_FLEX_ARRAY];
+} git_filter_def;
+
+static int filter_def_priority_cmp(const void *a, const void *b)
 {
-	int error;
+	int pa = ((const git_filter_def *)a)->priority;
+	int pb = ((const git_filter_def *)b)->priority;
+	return (pa < pb) ? -1 : (pa > pb) ? 1 : 0;
+}
 
-	if (mode == GIT_FILTER_TO_ODB) {
-		/* Load the CRLF cleanup filter when writing to the ODB */
-		error = git_filter_add__crlf_to_odb(filters, repo, path);
-		if (error < 0)
-			return error;
-	} else {
-		error = git_filter_add__crlf_to_workdir(filters, repo, path);
-		if (error < 0)
-			return error;
+struct filter_registry {
+	git_vector filters;
+};
+
+static struct filter_registry *git__filter_registry = NULL;
+
+static void filter_registry_shutdown(void)
+{
+	struct filter_registry *reg = NULL;
+	size_t pos;
+	git_filter_def *fdef;
+
+	if ((reg = git__swap(git__filter_registry, NULL)) == NULL)
+		return;
+
+	git_vector_foreach(&reg->filters, pos, fdef) {
+		if (fdef->initialized && fdef->filter && fdef->filter->shutdown) {
+			fdef->filter->shutdown(fdef->filter);
+			fdef->initialized = false;
+		}
+
+		git__free(fdef->attrdata);
+		git__free(fdef);
 	}
 
-	return (int)filters->length;
+	git_vector_free(&reg->filters);
+	git__free(reg);
 }
 
-void git_filters_free(git_vector *filters)
+static int filter_registry_initialize(void)
 {
-	size_t i;
-	git_filter *filter;
+	int error = 0;
+	struct filter_registry *reg;
+
+	if (git__filter_registry)
+		return 0;
+
+	reg = git__calloc(1, sizeof(struct filter_registry));
+	GITERR_CHECK_ALLOC(reg);
+
+	if ((error = git_vector_init(
+			&reg->filters, 2, filter_def_priority_cmp)) < 0)
+		goto cleanup;
+
+	reg = git__compare_and_swap(&git__filter_registry, NULL, reg);
+	if (reg != NULL)
+		goto cleanup;
+
+	git__on_shutdown(filter_registry_shutdown);
+
+	/* try to register both default filters */
+	{
+		git_filter *crlf = git_crlf_filter_new();
+		git_filter *ident = git_ident_filter_new();
+
+		if (crlf && git_filter_register(
+				GIT_FILTER_CRLF, crlf, GIT_FILTER_CRLF_PRIORITY) < 0)
+			crlf = NULL;
+		if (ident && git_filter_register(
+				GIT_FILTER_IDENT, ident, GIT_FILTER_IDENT_PRIORITY) < 0)
+			ident = NULL;
+
+		if (!crlf || !ident)
+			return -1;
+	}
+
+	return 0;
+
+cleanup:
+	git_vector_free(&reg->filters);
+	git__free(reg);
+	return error;
+}
+
+static int filter_def_scan_attrs(
+	git_buf *attrs, size_t *nattr, size_t *nmatch, const char *attr_str)
+{
+	const char *start, *scan = attr_str;
+	int has_eq;
+
+	*nattr = *nmatch = 0;
+
+	if (!scan)
+		return 0;
+
+	while (*scan) {
+		while (git__isspace(*scan)) scan++;
+
+		for (start = scan, has_eq = 0; *scan && !git__isspace(*scan); ++scan) {
+			if (*scan == '=')
+				has_eq = 1;
+		}
+
+		if (scan > start) {
+			(*nattr)++;
+			if (has_eq || *start == '-' || *start == '+' || *start == '!')
+				(*nmatch)++;
 
-	git_vector_foreach(filters, i, filter) {
-		if (filter->do_free != NULL)
-			filter->do_free(filter);
-		else
-			git__free(filter);
+			if (has_eq)
+				git_buf_putc(attrs, '=');
+			git_buf_put(attrs, start, scan - start);
+			git_buf_putc(attrs, '\0');
+		}
 	}
 
-	git_vector_free(filters);
+	return 0;
 }
 
-int git_filters_apply(git_buf *dest, git_buf *source, git_vector *filters)
+static void filter_def_set_attrs(git_filter_def *fdef)
 {
+	char *scan = fdef->attrdata;
 	size_t i;
-	unsigned int src;
-	git_buf *dbuffer[2];
 
-	dbuffer[0] = source;
-	dbuffer[1] = dest;
+	for (i = 0; i < fdef->nattrs; ++i) {
+		const char *name, *value;
+
+		switch (*scan) {
+		case '=':
+			name = scan + 1;
+			for (scan++; *scan != '='; scan++) /* find '=' */;
+			*scan++ = '\0';
+			value = scan;
+			break;
+		case '-':
+			name = scan + 1; value = git_attr__false; break;
+		case '+':
+			name = scan + 1; value = git_attr__true;  break;
+		case '!':
+			name = scan + 1; value = git_attr__unset; break;
+		default:
+			name = scan;     value = NULL; break;
+		}
+
+		fdef->attrs[i] = name;
+		fdef->attrs[i + fdef->nattrs] = value;
+
+		scan += strlen(scan) + 1;
+	}
+}
+
+static int filter_def_name_key_check(const void *key, const void *fdef)
+{
+	const char *name =
+		fdef ? ((const git_filter_def *)fdef)->filter_name : NULL;
+	return name ? git__strcmp(key, name) : -1;
+}
 
-	src = 0;
+static int filter_def_filter_key_check(const void *key, const void *fdef)
+{
+	const void *filter = fdef ? ((const git_filter_def *)fdef)->filter : NULL;
+	return (key == filter) ? 0 : -1;
+}
+
+static int filter_registry_find(size_t *pos, const char *name)
+{
+	return git_vector_search2(
+		pos, &git__filter_registry->filters, filter_def_name_key_check, name);
+}
 
-	if (git_buf_len(source) == 0) {
-		git_buf_clear(dest);
+static git_filter_def *filter_registry_lookup(size_t *pos, const char *name)
+{
+	git_filter_def *fdef = NULL;
+
+	if (!filter_registry_find(pos, name))
+		fdef = git_vector_get(&git__filter_registry->filters, *pos);
+
+	return fdef;
+}
+
+int git_filter_register(
+	const char *name, git_filter *filter, int priority)
+{
+	git_filter_def *fdef;
+	size_t nattr = 0, nmatch = 0;
+	git_buf attrs = GIT_BUF_INIT;
+
+	if (filter_registry_initialize() < 0)
+		return -1;
+
+	if (!filter_registry_find(NULL, name)) {
+		giterr_set(
+			GITERR_FILTER, "Attempt to reregister existing filter '%s'", name);
+		return GIT_EEXISTS;
+	}
+
+	if (filter_def_scan_attrs(&attrs, &nattr, &nmatch, filter->attributes) < 0)
+		return -1;
+
+	fdef = git__calloc(
+		sizeof(git_filter_def) + 2 * nattr * sizeof(char *), 1);
+	GITERR_CHECK_ALLOC(fdef);
+
+	fdef->filter_name = name;
+	fdef->filter      = filter;
+	fdef->priority    = priority;
+	fdef->nattrs      = nattr;
+	fdef->nmatches    = nmatch;
+	fdef->attrdata    = git_buf_detach(&attrs);
+
+	filter_def_set_attrs(fdef);
+
+	if (git_vector_insert(&git__filter_registry->filters, fdef) < 0) {
+		git__free(fdef->attrdata);
+		git__free(fdef);
+		return -1;
+	}
+
+	git_vector_sort(&git__filter_registry->filters);
+	return 0;
+}
+
+int git_filter_unregister(const char *name)
+{
+	size_t pos;
+	git_filter_def *fdef;
+
+	/* cannot unregister default filters */
+	if (!strcmp(GIT_FILTER_CRLF, name) || !strcmp(GIT_FILTER_IDENT, name)) {
+		giterr_set(GITERR_FILTER, "Cannot unregister filter '%s'", name);
+		return -1;
+	}
+
+	if ((fdef = filter_registry_lookup(&pos, name)) == NULL) {
+		giterr_set(GITERR_FILTER, "Cannot find filter '%s' to unregister", name);
+		return GIT_ENOTFOUND;
+	}
+
+	(void)git_vector_remove(&git__filter_registry->filters, pos);
+
+	if (fdef->initialized && fdef->filter && fdef->filter->shutdown) {
+		fdef->filter->shutdown(fdef->filter);
+		fdef->initialized = false;
+	}
+
+	git__free(fdef->attrdata);
+	git__free(fdef);
+
+	return 0;
+}
+
+static int filter_initialize(git_filter_def *fdef)
+{
+	int error = 0;
+
+	if (!fdef->initialized &&
+		fdef->filter &&
+		fdef->filter->initialize &&
+		(error = fdef->filter->initialize(fdef->filter)) < 0)
+	{
+		/* auto-unregister if initialize fails */
+		git_filter_unregister(fdef->filter_name);
+		return error;
+	}
+
+	fdef->initialized = true;
+	return 0;
+}
+
+git_filter *git_filter_lookup(const char *name)
+{
+	size_t pos;
+	git_filter_def *fdef;
+
+	if (filter_registry_initialize() < 0)
+		return NULL;
+
+	if ((fdef = filter_registry_lookup(&pos, name)) == NULL)
+		return NULL;
+
+	if (!fdef->initialized && filter_initialize(fdef) < 0)
+		return NULL;
+
+	return fdef->filter;
+}
+
+void git_filter_free(git_filter *filter)
+{
+	git__free(filter);
+}
+
+git_repository *git_filter_source_repo(const git_filter_source *src)
+{
+	return src->repo;
+}
+
+const char *git_filter_source_path(const git_filter_source *src)
+{
+	return src->path;
+}
+
+uint16_t git_filter_source_filemode(const git_filter_source *src)
+{
+	return src->filemode;
+}
+
+const git_oid *git_filter_source_id(const git_filter_source *src)
+{
+	return git_oid_iszero(&src->oid) ? NULL : &src->oid;
+}
+
+git_filter_mode_t git_filter_source_mode(const git_filter_source *src)
+{
+	return src->mode;
+}
+
+static int filter_list_new(
+	git_filter_list **out, const git_filter_source *src)
+{
+	git_filter_list *fl = NULL;
+	size_t pathlen = src->path ? strlen(src->path) : 0;
+
+	fl = git__calloc(1, sizeof(git_filter_list) + pathlen + 1);
+	GITERR_CHECK_ALLOC(fl);
+
+	if (src->path)
+		memcpy(fl->path, src->path, pathlen);
+	fl->source.repo = src->repo;
+	fl->source.path = fl->path;
+	fl->source.mode = src->mode;
+
+	*out = fl;
+	return 0;
+}
+
+static int filter_list_check_attributes(
+	const char ***out, git_filter_def *fdef, const git_filter_source *src)
+{
+	int error;
+	size_t i;
+	const char **strs = git__calloc(fdef->nattrs, sizeof(const char *));
+	GITERR_CHECK_ALLOC(strs);
+
+	error = git_attr_get_many(
+		strs, src->repo, 0, src->path, fdef->nattrs, fdef->attrs);
+
+	/* if no values were found but no matches are needed, it's okay! */
+	if (error == GIT_ENOTFOUND && !fdef->nmatches) {
+		giterr_clear();
+		git__free((void *)strs);
 		return 0;
 	}
 
-	/* Pre-grow the destination buffer to more or less the size
-	 * we expect it to have */
-	if (git_buf_grow(dest, git_buf_len(source)) < 0)
+	for (i = 0; !error && i < fdef->nattrs; ++i) {
+		const char *want = fdef->attrs[fdef->nattrs + i];
+		git_attr_t want_type, found_type;
+
+		if (!want)
+			continue;
+
+		want_type  = git_attr_value(want);
+		found_type = git_attr_value(strs[i]);
+
+		if (want_type != found_type ||
+			(want_type == GIT_ATTR_VALUE_T && strcmp(want, strs[i])))
+			error = GIT_ENOTFOUND;
+	}
+
+	if (error)
+		git__free((void *)strs);
+	else
+		*out = strs;
+
+	return error;
+}
+
+int git_filter_list_new(
+	git_filter_list **out, git_repository *repo, git_filter_mode_t mode)
+{
+	git_filter_source src = { 0 };
+	src.repo = repo;
+	src.path = NULL;
+	src.mode = mode;
+	return filter_list_new(out, &src);
+}
+
+int git_filter_list_load(
+	git_filter_list **filters,
+	git_repository *repo,
+	git_blob *blob, /* can be NULL */
+	const char *path,
+	git_filter_mode_t mode)
+{
+	int error = 0;
+	git_filter_list *fl = NULL;
+	git_filter_source src = { 0 };
+	git_filter_entry *fe;
+	size_t idx;
+	git_filter_def *fdef;
+
+	if (filter_registry_initialize() < 0)
+		return -1;
+
+	src.repo = repo;
+	src.path = path;
+	src.mode = mode;
+	if (blob)
+		git_oid_cpy(&src.oid, git_blob_id(blob));
+
+	git_vector_foreach(&git__filter_registry->filters, idx, fdef) {
+		const char **values = NULL;
+		void *payload = NULL;
+
+		if (!fdef || !fdef->filter)
+			continue;
+
+		if (fdef->nattrs > 0) {
+			error = filter_list_check_attributes(&values, fdef, &src);
+			if (error == GIT_ENOTFOUND) {
+				error = 0;
+				continue;
+			} else if (error < 0)
+				break;
+		}
+
+		if (!fdef->initialized && (error = filter_initialize(fdef)) < 0)
+			break;
+
+		if (fdef->filter->check)
+			error = fdef->filter->check(
+				fdef->filter, &payload, &src, values);
+
+		git__free((void *)values);
+
+		if (error == GIT_PASSTHROUGH)
+			error = 0;
+		else if (error < 0)
+			break;
+		else {
+			if (!fl && (error = filter_list_new(&fl, &src)) < 0)
+				return error;
+
+			fe = git_array_alloc(fl->filters);
+			GITERR_CHECK_ALLOC(fe);
+			fe->filter  = fdef->filter;
+			fe->payload = payload;
+		}
+	}
+
+	if (error && fl != NULL) {
+		git_array_clear(fl->filters);
+		git__free(fl);
+		fl = NULL;
+	}
+
+	*filters = fl;
+	return error;
+}
+
+void git_filter_list_free(git_filter_list *fl)
+{
+	uint32_t i;
+
+	if (!fl)
+		return;
+
+	for (i = 0; i < git_array_size(fl->filters); ++i) {
+		git_filter_entry *fe = git_array_get(fl->filters, i);
+		if (fe->filter->cleanup)
+			fe->filter->cleanup(fe->filter, fe->payload);
+	}
+
+	git_array_clear(fl->filters);
+	git__free(fl);
+}
+
+int git_filter_list_push(
+	git_filter_list *fl, git_filter *filter, void *payload)
+{
+	int error = 0;
+	size_t pos;
+	git_filter_def *fdef;
+	git_filter_entry *fe;
+
+	assert(fl && filter);
+
+	if (git_vector_search2(
+			&pos, &git__filter_registry->filters,
+			filter_def_filter_key_check, filter) < 0) {
+		giterr_set(GITERR_FILTER, "Cannot use an unregistered filter");
 		return -1;
+	}
+
+	fdef = git_vector_get(&git__filter_registry->filters, pos);
+
+	if (!fdef->initialized && (error = filter_initialize(fdef)) < 0)
+		return error;
+
+	fe = git_array_alloc(fl->filters);
+	GITERR_CHECK_ALLOC(fe);
+	fe->filter  = filter;
+	fe->payload = payload;
+
+	return 0;
+}
+
+size_t git_filter_list_length(const git_filter_list *fl)
+{
+	return fl ? git_array_size(fl->filters) : 0;
+}
+
+static int filter_list_out_buffer_from_raw(
+	git_buf *out, const void *ptr, size_t size)
+{
+	if (git_buf_is_allocated(out))
+		git_buf_free(out);
 
-	for (i = 0; i < filters->length; ++i) {
-		git_filter *filter = git_vector_get(filters, i);
-		unsigned int dst = 1 - src;
+	if (!size) {
+		git_buf_init(out, 0);
+	} else {
+		out->ptr   = (char *)ptr;
+		out->asize = 0;
+		out->size  = size;
+	}
+
+	return 0;
+}
+
+int git_filter_list_apply_to_data(
+	git_buf *tgt, git_filter_list *fl, git_buf *src)
+{
+	int error = 0;
+	uint32_t i;
+	git_buf *dbuffer[2], local = GIT_BUF_INIT;
+	unsigned int si = 0;
 
-		git_buf_clear(dbuffer[dst]);
+	if (!fl)
+		return filter_list_out_buffer_from_raw(tgt, src->ptr, src->size);
+
+	dbuffer[0] = src;
+	dbuffer[1] = tgt;
+
+	/* if `src` buffer is reallocable, then use it, otherwise copy it */
+	if (!git_buf_is_allocated(src)) {
+		if (git_buf_set(&local, src->ptr, src->size) < 0)
+			return -1;
+		dbuffer[0] = &local;
+	}
+
+	for (i = 0; i < git_array_size(fl->filters); ++i) {
+		unsigned int di = 1 - si;
+		uint32_t fidx = (fl->source.mode == GIT_FILTER_TO_WORKTREE) ?
+			i : git_array_size(fl->filters) - 1 - i;
+		git_filter_entry *fe = git_array_get(fl->filters, fidx);
+
+		dbuffer[di]->size = 0;
 
 		/* Apply the filter from dbuffer[src] to the other buffer;
 		 * if the filtering is canceled by the user mid-filter,
@@ -79,16 +605,72 @@ int git_filters_apply(git_buf *dest, git_buf *source, git_vector *filters)
 		 * of the double buffering (so that the text goes through
 		 * cleanly).
 		 */
-		if (filter->apply(filter, dbuffer[dst], dbuffer[src]) == 0)
-			src = dst;
 
-		if (git_buf_oom(dbuffer[dst]))
-			return -1;
+		error = fe->filter->apply(
+			fe->filter, &fe->payload, dbuffer[di], dbuffer[si], &fl->source);
+
+		if (error == GIT_PASSTHROUGH) {
+			/* PASSTHROUGH means filter decided not to process the buffer */
+			error = 0;
+		} else if (!error) {
+			git_buf_shorten(dbuffer[di], 0); /* force NUL termination */
+			si = di; /* swap buffers */
+		} else {
+			tgt->size = 0;
+			return error;
+		}
 	}
 
 	/* Ensure that the output ends up in dbuffer[1] (i.e. the dest) */
-	if (src != 1)
-		git_buf_swap(dest, source);
+	if (si != 1)
+		git_buf_swap(dbuffer[0], dbuffer[1]);
+
+	git_buf_free(&local); /* don't leak if we allocated locally */
 
 	return 0;
 }
+
+int git_filter_list_apply_to_file(
+	git_buf *out,
+	git_filter_list *filters,
+	git_repository *repo,
+	const char *path)
+{
+	int error;
+	const char *base = repo ? git_repository_workdir(repo) : NULL;
+	git_buf abspath = GIT_BUF_INIT, raw = GIT_BUF_INIT;
+
+	if (!(error = git_path_join_unrooted(&abspath, path, base, NULL)) &&
+		!(error = git_futils_readbuffer(&raw, abspath.ptr)))
+	{
+		error = git_filter_list_apply_to_data(out, filters, &raw);
+
+		git_buf_free(&raw);
+	}
+
+	git_buf_free(&abspath);
+	return error;
+}
+
+int git_filter_list_apply_to_blob(
+	git_buf *out,
+	git_filter_list *filters,
+	git_blob *blob)
+{
+	git_buf in = GIT_BUF_INIT;
+	git_off_t rawsize = git_blob_rawsize(blob);
+
+	if (!git__is_sizet(rawsize)) {
+		giterr_set(GITERR_OS, "Blob is too large to filter");
+		return -1;
+	}
+
+	in.ptr   = (char *)git_blob_rawcontent(blob);
+	in.asize = 0;
+	in.size  = (size_t)rawsize;
+
+	if (filters)
+		git_oid_cpy(&filters->source.oid, git_blob_id(blob));
+
+	return git_filter_list_apply_to_data(out, filters, &in);
+}