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Make 'traverse_tree()' use linked structure rather than 'const char *…
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…base'

This makes the calling convention a bit less obvious, but a lot more
flexible.  Instead of allocating and extending a new 'base' string, we
just link the top-most name into a linked list of the 'info' structure
when traversing a subdirectory, and we can generate the basename by
following the list.

Perhaps even more importantly, the linked list of info structures also
gives us a place to naturally save off other information than just the
directory name.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Linus Torvalds authored and Junio C Hamano committed Mar 9, 2008
1 parent 0ab9e1e commit 40d934d
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Showing 3 changed files with 78 additions and 28 deletions.
51 changes: 27 additions & 24 deletions merge-tree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -168,7 +168,13 @@ static struct merge_list *create_entry(unsigned stage, unsigned mode, const unsi
return res;
}

static void resolve(const char *base, struct name_entry *branch1, struct name_entry *result)
static char *traverse_path(const struct traverse_info *info, const struct name_entry *n)
{
char *path = xmalloc(traverse_path_len(info, n) + 1);
return make_traverse_path(path, info, n);
}

static void resolve(const struct traverse_info *info, struct name_entry *branch1, struct name_entry *result)
{
struct merge_list *orig, *final;
const char *path;
Expand All @@ -177,7 +183,7 @@ static void resolve(const char *base, struct name_entry *branch1, struct name_en
if (!branch1)
return;

path = xstrdup(mkpath("%s%s", base, result->path));
path = traverse_path(info, result);
orig = create_entry(2, branch1->mode, branch1->sha1, path);
final = create_entry(0, result->mode, result->sha1, path);

Expand All @@ -186,9 +192,8 @@ static void resolve(const char *base, struct name_entry *branch1, struct name_en
add_merge_entry(final);
}

static int unresolved_directory(const char *base, struct name_entry n[3])
static int unresolved_directory(const struct traverse_info *info, struct name_entry n[3])
{
int baselen, pathlen;
char *newbase;
struct name_entry *p;
struct tree_desc t[3];
Expand All @@ -204,13 +209,7 @@ static int unresolved_directory(const char *base, struct name_entry n[3])
}
if (!S_ISDIR(p->mode))
return 0;
baselen = strlen(base);
pathlen = tree_entry_len(p->path, p->sha1);
newbase = xmalloc(baselen + pathlen + 2);
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, p->path, pathlen);
memcpy(newbase + baselen + pathlen, "/", 2);

newbase = traverse_path(info, p);
buf0 = fill_tree_descriptor(t+0, n[0].sha1);
buf1 = fill_tree_descriptor(t+1, n[1].sha1);
buf2 = fill_tree_descriptor(t+2, n[2].sha1);
Expand All @@ -224,7 +223,7 @@ static int unresolved_directory(const char *base, struct name_entry n[3])
}


static struct merge_list *link_entry(unsigned stage, const char *base, struct name_entry *n, struct merge_list *entry)
static struct merge_list *link_entry(unsigned stage, const struct traverse_info *info, struct name_entry *n, struct merge_list *entry)
{
const char *path;
struct merge_list *link;
Expand All @@ -234,27 +233,27 @@ static struct merge_list *link_entry(unsigned stage, const char *base, struct na
if (entry)
path = entry->path;
else
path = xstrdup(mkpath("%s%s", base, n->path));
path = traverse_path(info, n);
link = create_entry(stage, n->mode, n->sha1, path);
link->link = entry;
return link;
}

static void unresolved(const char *base, struct name_entry n[3])
static void unresolved(const struct traverse_info *info, struct name_entry n[3])
{
struct merge_list *entry = NULL;

if (unresolved_directory(base, n))
if (unresolved_directory(info, n))
return;

/*
* Do them in reverse order so that the resulting link
* list has the stages in order - link_entry adds new
* links at the front.
*/
entry = link_entry(3, base, n + 2, entry);
entry = link_entry(2, base, n + 1, entry);
entry = link_entry(1, base, n + 0, entry);
entry = link_entry(3, info, n + 2, entry);
entry = link_entry(2, info, n + 1, entry);
entry = link_entry(1, info, n + 0, entry);

add_merge_entry(entry);
}
Expand Down Expand Up @@ -288,36 +287,40 @@ static void unresolved(const char *base, struct name_entry n[3])
* The successful merge rules are the same as for the three-way merge
* in git-read-tree.
*/
static void threeway_callback(int n, unsigned long mask, struct name_entry *entry, const char *base)
static void threeway_callback(int n, unsigned long mask, struct name_entry *entry, struct traverse_info *info)
{
/* Same in both? */
if (same_entry(entry+1, entry+2)) {
if (entry[0].sha1) {
resolve(base, NULL, entry+1);
resolve(info, NULL, entry+1);
return;
}
}

if (same_entry(entry+0, entry+1)) {
if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) {
resolve(base, entry+1, entry+2);
resolve(info, entry+1, entry+2);
return;
}
}

if (same_entry(entry+0, entry+2)) {
if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) {
resolve(base, NULL, entry+1);
resolve(info, NULL, entry+1);
return;
}
}

unresolved(base, entry);
unresolved(info, entry);
}

static void merge_trees(struct tree_desc t[3], const char *base)
{
traverse_trees(3, t, base, threeway_callback);
struct traverse_info info;

setup_traverse_info(&info, base);
info.fn = threeway_callback;
traverse_trees(3, t, &info);
}

static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
Expand Down
35 changes: 33 additions & 2 deletions tree-walk.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -104,7 +104,38 @@ int tree_entry(struct tree_desc *desc, struct name_entry *entry)
return 1;
}

void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
void setup_traverse_info(struct traverse_info *info, const char *base)
{
int pathlen = strlen(base);

memset(info, 0, sizeof(*info));
if (pathlen && base[pathlen-1] == '/')
pathlen--;
info->pathlen = pathlen ? pathlen + 1 : 0;
info->name.path = base;
info->name.sha1 = (void *)(base + pathlen + 1);
}

char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
{
int len = tree_entry_len(n->path, n->sha1);
int pathlen = info->pathlen;

path[pathlen + len] = 0;
for (;;) {
memcpy(path + pathlen, n->path, len);
if (!pathlen)
break;
path[--pathlen] = '/';
n = &info->name;
len = tree_entry_len(n->path, n->sha1);
info = info->prev;
pathlen -= len;
}
return path;
}

void traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
{
struct name_entry *entry = xmalloc(n*sizeof(*entry));

Expand Down Expand Up @@ -150,7 +181,7 @@ void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callb
}
entry_clear(entry + i);
}
callback(n, mask, entry, base);
info->fn(n, mask, entry, info);
}
free(entry);
}
Expand Down
20 changes: 18 additions & 2 deletions tree-walk.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,10 +33,26 @@ int tree_entry(struct tree_desc *, struct name_entry *);

void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1);

typedef void (*traverse_callback_t)(int n, unsigned long mask, struct name_entry *entry, const char *base);
struct traverse_info;
typedef void (*traverse_callback_t)(int n, unsigned long mask, struct name_entry *entry, struct traverse_info *);
void traverse_trees(int n, struct tree_desc *t, struct traverse_info *info);

void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback);
struct traverse_info {
struct traverse_info *prev;
struct name_entry name;
int pathlen;

traverse_callback_t fn;
void *data;
};

int get_tree_entry(const unsigned char *, const char *, unsigned char *, unsigned *);
extern char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n);
extern void setup_traverse_info(struct traverse_info *info, const char *base);

static inline int traverse_path_len(const struct traverse_info *info, const struct name_entry *n)
{
return info->pathlen + tree_entry_len(n->path, n->sha1);
}

#endif

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