merge-recursive: change current file dir string_lists to hashmap

The code was using two string_lists, one for the directories and
one for the files.  The code never checks the lists independently
so we should be able to only use one list.  The string_list also
is a O(log n) for lookup and insertion.  Switching this to use a
hashmap will give O(1) which will save some time when there are
millions of paths that will be checked.

Signed-off-by: Kevin Willford <kewillf@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/merge-recursive.c b/merge-recursive.c
index d47f40ea8151e48b0a988fcfd3521728dd977317..35af3761baf61c523b27c64e6b7e5cf3c55adb26 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -24,6 +24,31 @@
 #include "dir.h"
 #include "submodule.h"
 
 #include "dir.h"
 #include "submodule.h"
 

+struct path_hashmap_entry {
+       struct hashmap_entry e;
+       char path[FLEX_ARRAY];
+};
+
+static int path_hashmap_cmp(const void *cmp_data,
+                           const void *entry,
+                           const void *entry_or_key,
+                           const void *keydata)
+{
+       const struct path_hashmap_entry *a = entry;
+       const struct path_hashmap_entry *b = entry_or_key;
+       const char *key = keydata;
+
+       if (ignore_case)
+               return strcasecmp(a->path, key ? key : b->path);
+       else
+               return strcmp(a->path, key ? key : b->path);
+}
+
+static unsigned int path_hash(const char *path)
+{
+       return ignore_case ? strihash(path) : strhash(path);
+}
+

 static void flush_output(struct merge_options *o)
 {
        if (o->buffer_output < 2 && o->obuf.len) {
 static void flush_output(struct merge_options *o)
 {
        if (o->buffer_output < 2 && o->obuf.len) {


@@ -314,15 +339,15 @@ static int save_files_dirs(const unsigned char *sha1,
                struct strbuf *base, const char *path,
                unsigned int mode, int stage, void *context)
 {
                struct strbuf *base, const char *path,
                unsigned int mode, int stage, void *context)
 {

+       struct path_hashmap_entry *entry;

        int baselen = base->len;
        struct merge_options *o = context;
 
        strbuf_addstr(base, path);
 
        int baselen = base->len;
        struct merge_options *o = context;
 
        strbuf_addstr(base, path);
 

-       if (S_ISDIR(mode))
-               string_list_insert(&o->current_directory_set, base->buf);
-       else
-               string_list_insert(&o->current_file_set, base->buf);
+       FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
+       hashmap_entry_init(entry, path_hash(entry->path));
+       hashmap_add(&o->current_file_dir_set, entry);

 
        strbuf_setlen(base, baselen);
        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 
        strbuf_setlen(base, baselen);
        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);


@@ -642,6 +667,7 @@ static void add_flattened_path(struct strbuf *out, const char *s)
 
 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 {
 
 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 {

+       struct path_hashmap_entry *entry;

        struct strbuf newpath = STRBUF_INIT;
        int suffix = 0;
        size_t base_len;
        struct strbuf newpath = STRBUF_INIT;
        int suffix = 0;
        size_t base_len;


@@ -650,14 +676,16 @@ static char *unique_path(struct merge_options *o, const char *path, const char *
        add_flattened_path(&newpath, branch);
 
        base_len = newpath.len;
        add_flattened_path(&newpath, branch);
 
        base_len = newpath.len;

-       while (string_list_has_string(&o->current_file_set, newpath.buf) ||
-              string_list_has_string(&o->current_directory_set, newpath.buf) ||
+       while (hashmap_get_from_hash(&o->current_file_dir_set,
+                                    path_hash(newpath.buf), newpath.buf) ||

               (!o->call_depth && file_exists(newpath.buf))) {
                strbuf_setlen(&newpath, base_len);
                strbuf_addf(&newpath, "_%d", suffix++);
        }
 
               (!o->call_depth && file_exists(newpath.buf))) {
                strbuf_setlen(&newpath, base_len);
                strbuf_addf(&newpath, "_%d", suffix++);
        }
 

-       string_list_insert(&o->current_file_set, newpath.buf);
+       FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
+       hashmap_entry_init(entry, path_hash(entry->path));
+       hashmap_add(&o->current_file_dir_set, entry);

        return strbuf_detach(&newpath, NULL);
 }
 
        return strbuf_detach(&newpath, NULL);
 }
 


@@ -1941,8 +1969,14 @@ int merge_trees(struct merge_options *o,
        if (unmerged_cache()) {
                struct string_list *entries, *re_head, *re_merge;
                int i;
        if (unmerged_cache()) {
                struct string_list *entries, *re_head, *re_merge;
                int i;

-               string_list_clear(&o->current_file_set, 1);
-               string_list_clear(&o->current_directory_set, 1);
+               /*
+                * Only need the hashmap while processing entries, so
+                * initialize it here and free it when we are done running
+                * through the entries. Keeping it in the merge_options as
+                * opposed to decaring a local hashmap is for convenience
+                * so that we don't have to pass it to around.
+                */
+               hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);

                get_files_dirs(o, head);
                get_files_dirs(o, merge);
 
                get_files_dirs(o, head);
                get_files_dirs(o, merge);
 


@@ -1978,6 +2012,8 @@ int merge_trees(struct merge_options *o,
                string_list_clear(re_head, 0);
                string_list_clear(entries, 1);
 
                string_list_clear(re_head, 0);
                string_list_clear(entries, 1);
 

+               hashmap_free(&o->current_file_dir_set, 1);
+

                free(re_merge);
                free(re_head);
                free(entries);
                free(re_merge);
                free(re_head);
                free(entries);


@@ -2179,8 +2215,6 @@ void init_merge_options(struct merge_options *o)
        if (o->verbosity >= 5)
                o->buffer_output = 0;
        strbuf_init(&o->obuf, 0);
        if (o->verbosity >= 5)
                o->buffer_output = 0;
        strbuf_init(&o->obuf, 0);

-       string_list_init(&o->current_file_set, 1);
-       string_list_init(&o->current_directory_set, 1);

        string_list_init(&o->df_conflict_file_set, 1);
 }
 
        string_list_init(&o->df_conflict_file_set, 1);
 }
 

diff --git a/merge-recursive.h b/merge-recursive.h
index 735343b4136d998ee3d2ac3672bdd7b5a5ba017e..80d69d140195cc3ba1054050569e56bfc0277b56 100644 (file)
--- a/merge-recursive.h
+++ b/merge-recursive.h
@@ -25,8 +25,7 @@ struct merge_options {
        int show_rename_progress;
        int call_depth;
        struct strbuf obuf;
        int show_rename_progress;
        int call_depth;
        struct strbuf obuf;

-       struct string_list current_file_set;
-       struct string_list current_directory_set;
+       struct hashmap current_file_dir_set;

        struct string_list df_conflict_file_set;
 };
 
        struct string_list df_conflict_file_set;
 };