[GSoC][PATCH v7 25/26] stash: replace all `write-tree` child processes with API calls

[Paul-Sebastian Ungureanu]

This commit replaces spawning `git write-tree` with API calls.
---
 builtin/stash.c | 40 ++++++++++++----------------------------
 1 file changed, 12 insertions(+), 28 deletions(-)

diff --git a/builtin/stash.c b/builtin/stash.c
index 4d5c0d16e..46e76a34e 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -949,9 +949,8 @@ static int save_untracked_files(struct stash_info *info, 
struct strbuf *msg)
 {
        int ret = 0;
        struct strbuf untracked_msg = STRBUF_INIT;
-       struct strbuf out2 = STRBUF_INIT;
        struct child_process cp = CHILD_PROCESS_INIT;
-       struct child_process cp2 = CHILD_PROCESS_INIT;
+       struct index_state state = { NULL };
 
        cp.git_cmd = 1;
        argv_array_pushl(&cp.args, "update-index", "--add",
@@ -966,15 +965,11 @@ static int save_untracked_files(struct stash_info *info, 
struct strbuf *msg)
                goto done;
        }
 
-       cp2.git_cmd = 1;
-       argv_array_push(&cp2.args, "write-tree");
-       argv_array_pushf(&cp2.env_array, "GIT_INDEX_FILE=%s",
-                        stash_index_path.buf);
-       if (pipe_command(&cp2, NULL, 0, &out2, 0,NULL, 0)) {
+       if (write_index_as_tree(&info->u_tree, &state, stash_index_path.buf, 0,
+                               NULL)) {
                ret = -1;
                goto done;
        }
-       get_oid_hex(out2.buf, &info->u_tree);
 
        if (commit_tree(untracked_msg.buf, untracked_msg.len,
                        &info->u_tree, NULL, &info->u_commit, NULL, NULL)) {
@@ -984,7 +979,6 @@ static int save_untracked_files(struct stash_info *info, 
struct strbuf *msg)
 
 done:
        strbuf_release(&untracked_msg);
-       strbuf_release(&out2);
        remove_path(stash_index_path.buf);
        return ret;
 }
@@ -994,11 +988,10 @@ static struct strbuf patch = STRBUF_INIT;
 static int stash_patch(struct stash_info *info, const char **argv)
 {
        int ret = 0;
-       struct strbuf out2 = STRBUF_INIT;
        struct child_process cp0 = CHILD_PROCESS_INIT;
        struct child_process cp1 = CHILD_PROCESS_INIT;
-       struct child_process cp2 = CHILD_PROCESS_INIT;
        struct child_process cp3 = CHILD_PROCESS_INIT;
+       struct index_state state = { NULL };
 
        remove_path(stash_index_path.buf);
 
@@ -1023,17 +1016,12 @@ static int stash_patch(struct stash_info *info, const 
char **argv)
                goto done;
        }
 
-       cp2.git_cmd = 1;
-       argv_array_push(&cp2.args, "write-tree");
-       argv_array_pushf(&cp2.env_array, "GIT_INDEX_FILE=%s",
-                        stash_index_path.buf);
-       if (pipe_command(&cp2, NULL, 0, &out2, 0,NULL, 0)) {
+       if (write_index_as_tree(&info->w_tree, &state, stash_index_path.buf, 0,
+                               NULL)) {
                ret = -1;
                goto done;
        }
 
-       get_oid_hex(out2.buf, &info->w_tree);
-
        cp3.git_cmd = 1;
        argv_array_pushl(&cp3.args, "diff-tree", "-p", "HEAD",
                         oid_to_hex(&info->w_tree), "--", NULL);
@@ -1046,7 +1034,6 @@ static int stash_patch(struct stash_info *info, const 
char **argv)
        }
 
 done:
-       strbuf_release(&out2);
        remove_path(stash_index_path.buf);
        return ret;
 }
@@ -1056,11 +1043,10 @@ static int stash_working_tree(struct stash_info *info,
 {
        int ret = 0;
        struct child_process cp2 = CHILD_PROCESS_INIT;
-       struct child_process cp3 = CHILD_PROCESS_INIT;
-       struct strbuf out3 = STRBUF_INIT;
        struct argv_array args = ARGV_ARRAY_INIT;
        struct strbuf diff_output = STRBUF_INIT;
        struct rev_info rev;
+       struct index_state state = { NULL };
 
        set_alternate_index_output(stash_index_path.buf);
        if (reset_tree(&info->i_tree, 0, 0)) {
@@ -1103,20 +1089,18 @@ static int stash_working_tree(struct stash_info *info,
                goto done;
        }
 
-       cp3.git_cmd = 1;
-       argv_array_push(&cp3.args, "write-tree");
-       argv_array_pushf(&cp3.env_array, "GIT_INDEX_FILE=%s",
-                        stash_index_path.buf);
-       if (pipe_command(&cp3, NULL, 0, &out3, 0,NULL, 0)) {
+       if (write_index_as_tree(&info->w_tree, &state, stash_index_path.buf, 0,
+                               NULL)) {
+
                ret = -1;
                goto done;
        }
 
-       get_oid_hex(out3.buf, &info->w_tree);
+       discard_cache();
+       read_cache();
 
 done:
        UNLEAK(rev);
-       strbuf_release(&out3);
        argv_array_clear(&args);
        object_array_clear(&rev.pending);
        strbuf_release(&diff_output);
-- 
2.18.0.573.g56500d98f