Subject: [PATCH v6 1/3] ref-filter: add worktreepath atom

From: [email-masked]
Date: Tue, 22 Jan 2019 15:22:59 -0800

From: Nickolai Belakovski <[email-masked]>

Add an atom providing the path of the linked worktree where this ref is
checked out, if it is checked out in any linked worktrees, and empty
string otherwise.
---
 Documentation/git-for-each-ref.txt |  5 +++
 ref-filter.c                       | 74 ++++++++++++++++++++++++++++++++++++++
 t/t6302-for-each-ref-filter.sh     | 15 ++++++++
 3 files changed, 94 insertions(+)

diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 774cecc7ed..6dcd39f6f6 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -214,6 +214,11 @@ symref::
 	`:lstrip` and `:rstrip` options in the same way as `refname`
 	above.
 
+worktreepath::
+	The absolute path to the worktree in which the ref is checked
+	out, if it is checked out in any linked worktree. Empty string
+	otherwise.
+
 In addition to the above, for commit and tag objects, the header
 field names (`tree`, `parent`, `object`, `type`, and `tag`) can
 be used to specify the value in the header field.
diff --git a/ref-filter.c b/ref-filter.c
index 422a9c9ae3..3c056cc148 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -20,6 +20,8 @@
 #include "commit-slab.h"
 #include "commit-graph.h"
 #include "commit-reach.h"
+#include "worktree.h"
+#include "hashmap.h"
 
 static struct ref_msg {
 	const char *gone;
@@ -75,6 +77,22 @@ static struct expand_data {
 	struct object_info info;
 } oi, oi_deref;
 
+struct ref_to_worktree_entry {
+	struct hashmap_entry ent; /* must be the first member! */
+	struct worktree *wt; /* key is wt->head_ref */
+};
+
+static int ref_to_worktree_map_cmpfnc(const void *unused_lookupdata, const void *existing_hashmap_entry_to_test,
+				   const void *key, const void *keydata_aka_refname)
+{
+	const struct ref_to_worktree_entry *e = existing_hashmap_entry_to_test;
+	const struct ref_to_worktree_entry *k = key;
+	return strcmp(e->wt->head_ref, keydata_aka_refname ? keydata_aka_refname : k->wt->head_ref);
+}
+
+static struct hashmap ref_to_worktree_map;
+static struct worktree **worktrees = NULL;
+
 /*
  * An atom is a valid field atom listed below, possibly prefixed with
  * a "*" to denote deref_tag().
@@ -438,6 +456,34 @@ static int head_atom_parser(const struct ref_format *format, struct used_atom *a
 	return 0;
 }
 
+static int worktree_atom_parser(const struct ref_format *format,
+				struct used_atom *atom,
+				const char *arg,
+				struct strbuf *unused_err)
+{
+	int i;
+
+	if (worktrees)
+		return 0;
+
+	worktrees = get_worktrees(0);
+
+	hashmap_init(&ref_to_worktree_map, ref_to_worktree_map_cmpfnc, NULL, 0);
+
+	for (i = 0; worktrees[i]; i++) {
+		if (worktrees[i]->head_ref) {
+			struct ref_to_worktree_entry *entry;
+			entry = xmalloc(sizeof(*entry));
+			entry->wt = worktrees[i];
+			hashmap_entry_init(entry, strhash(worktrees[i]->head_ref));
+
+			hashmap_add(&ref_to_worktree_map, entry);
+		}
+	}
+
+	return 0;
+}
+
 static struct {
 	const char *name;
 	info_source source;
@@ -480,6 +526,7 @@ static struct {
 	{ "flag", SOURCE_NONE },
 	{ "HEAD", SOURCE_NONE, FIELD_STR, head_atom_parser },
 	{ "color", SOURCE_NONE, FIELD_STR, color_atom_parser },
+	{ "worktreepath", SOURCE_NONE, FIELD_STR, worktree_atom_parser },
 	{ "align", SOURCE_NONE, FIELD_STR, align_atom_parser },
 	{ "end", SOURCE_NONE },
 	{ "if", SOURCE_NONE, FIELD_STR, if_atom_parser },
@@ -1525,6 +1572,21 @@ static int get_object(struct ref_array_item *ref, int deref, struct object **obj
 	return 0;
 }
 
+static char *get_worktree_path(const struct used_atom *atom, const struct ref_array_item *ref)
+{
+	struct strbuf val = STRBUF_INIT;
+	struct hashmap_entry entry;
+	struct ref_to_worktree_entry *lookup_result;
+
+	hashmap_entry_init(&entry, strhash(ref->refname));
+	lookup_result = hashmap_get(&ref_to_worktree_map, &entry, ref->refname);
+
+	if (lookup_result)
+		strbuf_addstr(&val, lookup_result->wt->path);
+
+	return strbuf_detach(&val, NULL);
+}
+
 /*
  * Parse the object referred by ref, and grab needed value.
  */
@@ -1562,6 +1624,13 @@ static int populate_value(struct ref_array_item *ref, struct strbuf *err)
 
 		if (starts_with(name, "refname"))
 			refname = get_refname(atom, ref);
+		else if (starts_with(name, "worktreepath")) {
+			if (ref->kind == FILTER_REFS_BRANCHES)
+				v->s = get_worktree_path(atom, ref);
+			else
+				v->s = xstrdup("");
+			continue;
+		}
 		else if (starts_with(name, "symref"))
 			refname = get_symref(atom, ref);
 		else if (starts_with(name, "upstream")) {
@@ -2045,6 +2114,11 @@ void ref_array_clear(struct ref_array *array)
 		free_array_item(array->items[i]);
 	FREE_AND_NULL(array->items);
 	array->nr = array->alloc = 0;
+	if (worktrees) {
+		hashmap_free(&ref_to_worktree_map, 1);
+		free_worktrees(worktrees);
+		worktrees = NULL;
+	}
 }
 
 static void do_merge_filter(struct ref_filter_cbdata *ref_cbdata)
diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
index fc067ed672..87e0222ea1 100755
--- a/t/t6302-for-each-ref-filter.sh
+++ b/t/t6302-for-each-ref-filter.sh
@@ -441,4 +441,19 @@ test_expect_success '--merged is incompatible with --no-merged' '
 	test_must_fail git for-each-ref --merged HEAD --no-merged HEAD
 '
 
+test_expect_success '"add" a worktree' '
+	mkdir worktree_dir &&
+	git worktree add -b master_worktree worktree_dir master
+'
+
+test_expect_success 'validate worktree atom' '
+	cat >expect <<-EOF &&
+	master: $(pwd)
+	master_worktree: $(pwd)/worktree_dir
+	side: not checked out
+	EOF
+	git for-each-ref --format="%(refname:short): %(if)%(worktreepath)%(then)%(worktreepath)%(else)not checked out%(end)" refs/heads/ >actual &&
+	test_cmp expect actual
+'
+
 test_done
-- 
2.14.2