[PATCH v2 03/10] cache-tree.c: dump "TREE" extension as json

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 cache-tree.c             | 36 +++++++++++++++++++++++++++++++-----
 cache-tree.h             |  5 ++++-
 read-cache.c             |  2 +-
 t/t3011-ls-files-json.sh |  4 +++-
 t/t3011/basic            | 20 +++++++++++++++++++-
 5 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/cache-tree.c b/cache-tree.c
index b13bfaf71e..b6a233307e 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -3,6 +3,7 @@
 #include "tree.h"
 #include "tree-walk.h"
 #include "cache-tree.h"
+#include "json-writer.h"
 #include "object-store.h"
 #include "replace-object.h"
 
@@ -492,7 +493,8 @@ void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 	write_one(sb, root, "", 0);
 }
 
-static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
+static struct cache_tree *read_one(const char **buffer, unsigned long *size_p,
+				   struct json_writer *jw)
 {
 	const char *buf = *buffer;
 	unsigned long size = *size_p;
@@ -546,6 +548,15 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 			*buffer, subtree_nr);
 #endif
 
+	if (jw) {
+		if (it->entry_count >= 0) {
+			jw_object_string(jw, "oid", oid_to_hex(&it->oid));
+			jw_object_intmax(jw, "entry_count", it->entry_count);
+		} else {
+			jw_object_null(jw, "oid");
+		}
+		jw_object_inline_begin_array(jw, "subdirs");
+	}
 	/*
 	 * Just a heuristic -- we do not add directories that often but
 	 * we do not want to have to extend it immediately when we do,
@@ -559,12 +570,18 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 		struct cache_tree_sub *subtree;
 		const char *name = buf;
 
-		sub = read_one(&buf, &size);
+		if (jw) {
+			jw_array_inline_begin_object(jw);
+			jw_object_string(jw, "name", name);
+		}
+		sub = read_one(&buf, &size, jw);
+		jw_end_gently(jw);
 		if (!sub)
 			goto free_return;
 		subtree = cache_tree_sub(it, name);
 		subtree->cache_tree = sub;
 	}
+	jw_end_gently(jw);
 	if (subtree_nr != it->subtree_nr)
 		die("cache-tree: internal error");
 	*buffer = buf;
@@ -576,11 +593,20 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 	return NULL;
 }
 
-struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
+struct cache_tree *cache_tree_read(const char *buffer, unsigned long size,
+				   struct json_writer *jw)
 {
+	struct cache_tree *ret;
+
+	if (jw) {
+		jw_object_inline_begin_object(jw, "root");
+	}
 	if (buffer[0])
-		return NULL; /* not the whole tree */
-	return read_one(&buffer, &size);
+		ret = NULL; /* not the whole tree */
+	else
+		ret = read_one(&buffer, &size, jw);
+	jw_end_gently(jw);
+	return ret;
 }
 
 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
diff --git a/cache-tree.h b/cache-tree.h
index 757bbc48bc..fc3c73284b 100644
--- a/cache-tree.h
+++ b/cache-tree.h
@@ -6,6 +6,8 @@
 #include "tree-walk.h"
 
 struct cache_tree;
+struct json_writer;
+
 struct cache_tree_sub {
 	struct cache_tree *cache_tree;
 	int count;		/* internally used by update_one() */
@@ -28,7 +30,8 @@ void cache_tree_invalidate_path(struct index_state *, const char *);
 struct cache_tree_sub *cache_tree_sub(struct cache_tree *, const char *);
 
 void cache_tree_write(struct strbuf *, struct cache_tree *root);
-struct cache_tree *cache_tree_read(const char *buffer, unsigned long size);
+struct cache_tree *cache_tree_read(const char *buffer, unsigned long size,
+				   struct json_writer *jw);
 
 int cache_tree_fully_valid(struct cache_tree *);
 int cache_tree_update(struct index_state *, int);
diff --git a/read-cache.c b/read-cache.c
index 4accd8bb08..d09ce42b9a 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1716,7 +1716,7 @@ static int read_index_extension(struct index_state *istate,
 
 	switch (CACHE_EXT(ext)) {
 	case CACHE_EXT_TREE:
-		istate->cache_tree = cache_tree_read(data, sz);
+		istate->cache_tree = cache_tree_read(data, sz, istate->jw);
 		break;
 	case CACHE_EXT_RESOLVE_UNDO:
 		istate->resolve_undo = resolve_undo_read(data, sz);
diff --git a/t/t3011-ls-files-json.sh b/t/t3011-ls-files-json.sh
index 97bcd814be..fc313f2c9a 100755
--- a/t/t3011-ls-files-json.sh
+++ b/t/t3011-ls-files-json.sh
@@ -29,6 +29,8 @@ test_expect_success 'setup' '
 	echo 2 >sub/two &&
 	git add sub/two &&
 
+	git commit -m first &&
+
 	echo intent-to-add >ita &&
 	git add -N ita &&
 
@@ -37,7 +39,7 @@ test_expect_success 'setup' '
 	strip_string oid ident
 '
 
-test_expect_success 'ls-files --json, main entries' '
+test_expect_success 'ls-files --json, main entries and TREE' '
 	compare_json basic
 '
 
diff --git a/t/t3011/basic b/t/t3011/basic
index 9436445d90..e27f5be5ff 100644
--- a/t/t3011/basic
+++ b/t/t3011/basic
@@ -63,5 +63,23 @@
       },
       "file_offset": <number>
     }
-  ]
+  ],
+  "extensions": {
+    "TREE": {
+      "file_offset": <number>,
+      "ext_size": <number>,
+      "root": {
+        "oid": null,
+        "subdirs": [
+          {
+            "name": "sub",
+            "oid": <string>,
+            "entry_count": 1,
+            "subdirs": [
+            ]
+          }
+        ]
+      }
+    }
+  }
 }
-- 
2.22.0.rc0.322.g2b0371e29a