git

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#include "git-compat-util.h"
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#include "gettext.h"
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#include "hex.h"
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#include "oidmap.h"
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#include "object-store-ll.h"
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#include "replace-object.h"
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#include "refs.h"
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#include "repository.h"
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#include "commit.h"
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static int register_replace_ref(const char *refname,
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				const char *referent UNUSED,
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				const struct object_id *oid,
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				int flag UNUSED,
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				void *cb_data)
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{
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	struct repository *r = cb_data;
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	/* Get sha1 from refname */
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	const char *slash = strrchr(refname, '/');
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	const char *hash = slash ? slash + 1 : refname;
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	struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
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	if (get_oid_hex_algop(hash, &repl_obj->original.oid, r->hash_algo)) {
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		free(repl_obj);
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		warning(_("bad replace ref name: %s"), refname);
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		return 0;
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	}
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	/* Copy sha1 from the read ref */
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	oidcpy(&repl_obj->replacement, oid);
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	/* Register new object */
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	if (oidmap_put(r->objects->replace_map, repl_obj))
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		die(_("duplicate replace ref: %s"), refname);
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	return 0;
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}
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void prepare_replace_object(struct repository *r)
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{
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	if (r->objects->replace_map_initialized)
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		return;
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	pthread_mutex_lock(&r->objects->replace_mutex);
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	if (r->objects->replace_map_initialized) {
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		pthread_mutex_unlock(&r->objects->replace_mutex);
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		return;
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	}
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	r->objects->replace_map =
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		xmalloc(sizeof(*r->objects->replace_map));
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	oidmap_init(r->objects->replace_map, 0);
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	refs_for_each_replace_ref(get_main_ref_store(r),
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				  register_replace_ref, r);
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	r->objects->replace_map_initialized = 1;
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	pthread_mutex_unlock(&r->objects->replace_mutex);
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}
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/* We allow "recursive" replacement. Only within reason, though */
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#define MAXREPLACEDEPTH 5
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/*
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 * If a replacement for object oid has been set up, return the
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 * replacement object's name (replaced recursively, if necessary).
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 * The return value is either oid or a pointer to a
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 * permanently-allocated value.  This function always respects replace
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 * references, regardless of the value of r->settings.read_replace_refs.
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 */
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const struct object_id *do_lookup_replace_object(struct repository *r,
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						 const struct object_id *oid)
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{
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	int depth = MAXREPLACEDEPTH;
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	const struct object_id *cur = oid;
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	prepare_replace_object(r);
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	/* Try to recursively replace the object */
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	while (depth-- > 0) {
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		struct replace_object *repl_obj =
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			oidmap_get(r->objects->replace_map, cur);
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		if (!repl_obj)
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			return cur;
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		cur = &repl_obj->replacement;
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	}
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	die(_("replace depth too high for object %s"), oid_to_hex(oid));
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}
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/*
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 * This indicator determines whether replace references should be
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 * respected process-wide, regardless of which repository is being
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 * using at the time.
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 */
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static int read_replace_refs = 1;
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void disable_replace_refs(void)
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{
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	read_replace_refs = 0;
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}
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int replace_refs_enabled(struct repository *r)
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{
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	if (!read_replace_refs)
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		return 0;
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	if (r->gitdir) {
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		prepare_repo_settings(r);
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		return r->settings.read_replace_refs;
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	}
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	/* repository has no objects or refs. */
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	return 0;
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}
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