thodg/libgit2

diff --git a/include/git2.h b/include/git2.h
index 1711ff8..7d053c4 100644
--- a/include/git2.h
+++ b/include/git2.h
@@ -40,7 +40,7 @@
 #include "git2/net.h"
 #include "git2/status.h"
 #include "git2/indexer.h"
-
+#include "git2/submodule.h"
 #include "git2/notes.h"
 
 #endif
diff --git a/include/git2/submodule.h b/include/git2/submodule.h
new file mode 100644
index 0000000..aee2260
--- /dev/null
+++ b/include/git2/submodule.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_submodule_h__
+#define INCLUDE_git_submodule_h__
+
+#include "common.h"
+#include "types.h"
+#include "oid.h"
+
+/**
+ * @file git2/submodule.h
+ * @brief Git submodule management utilities
+ * @defgroup git_submodule Git submodule management routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+typedef enum {
+	GIT_SUBMODULE_UPDATE_CHECKOUT = 0,
+	GIT_SUBMOUDLE_UPDATE_REBASE = 1,
+	GIT_SUBMODULE_UPDATE_MERGE = 2
+} git_submodule_update_t;
+
+typedef enum {
+	GIT_SUBMODULE_IGNORE_ALL = 0,       /* never dirty */
+	GIT_SUBMODULE_IGNORE_DIRTY = 1,     /* only dirty if HEAD moved */
+	GIT_SUBMODULE_IGNORE_UNTRACKED = 2, /* dirty if tracked files change */
+	GIT_SUBMODULE_IGNORE_NONE = 3       /* any change or untracked == dirty */
+} git_submodule_ignore_t;
+
+/**
+ * Description of submodule
+ *
+ * This record describes a submodule found in a repository.  There
+ * should be an entry for every submodule found in the HEAD and for
+ * every submodule described in .gitmodules.  The fields are as follows:
+ *
+ * - `name` is the name of the submodule from .gitmodules.
+ * - `path` is the path to the submodule from the repo working directory.
+ *   It is almost always the same as `name`.
+ * - `url` is the url for the submodule.
+ * - `oid` is the HEAD SHA1 for the submodule.
+ * - `update` is a value from above - see gitmodules(5) update.
+ * - `ignore` is a value from above - see gitmodules(5) ignore.
+ * - `fetch_recurse` is 0 or 1 - see gitmodules(5) fetchRecurseSubmodules.
+ * - `refcount` is for internal use.
+ *
+ * If the submodule has been added to .gitmodules but not yet git added,
+ * then the `oid` will be zero.  If the submodule has been deleted, but
+ * the delete has not been committed yet, then the `oid` will be set, but
+ * the `url` will be NULL.
+ */
+typedef struct {
+	char *name;
+	char *path;
+	char *url;
+	git_oid oid; /* sha1 of submodule HEAD ref or zero if not committed */
+	git_submodule_update_t update;
+	git_submodule_ignore_t ignore;
+	int fetch_recurse;
+	int refcount;
+} git_submodule;
+
+/**
+ * Iterate over all submodules of a repository.
+ *
+ * @param repo The repository
+ * @param callback Function to be called with the name of each submodule.
+ *        Return a non-zero value to terminate the iteration.
+ * @param payload Extra data to pass to callback
+ * @return 0 on success, -1 on error, or non-zero return value of callback
+ */
+GIT_EXTERN(int) git_submodule_foreach(
+	git_repository *repo,
+	int (*callback)(const char *name, void *payload),
+	void *payload);
+
+#define GIT_SUBMODULE_HEAD "[internal]HEAD"
+
+/**
+ * Lookup submodule information by name or path.
+ *
+ * Given either the submodule name or path (they are ususally the same),
+ * this returns a structure describing the submodule.  If the submodule
+ * does not exist, this will return GIT_ENOTFOUND and set the submodule
+ * pointer to NULL.
+ *
+ * @param submodule Pointer to submodule description object pointer..
+ * @param repo The repository.
+ * @param name The name of the submodule.  Trailing slashes will be ignored.
+ * @return 0 on success, GIT_ENOTFOUND if submodule does not exist, -1 on error
+ */
+GIT_EXTERN(int) git_submodule_lookup(
+	git_submodule **submodule,
+	git_repository *repo,
+	const char *name);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/src/config.c b/src/config.c
index 77598d6..5ef1a24 100644
--- a/src/config.c
+++ b/src/config.c
@@ -201,7 +201,7 @@ int git_config_set_string(git_config *cfg, const char *name, const char *value)
 	return file->set(file, name, value);
 }
 
-static int parse_bool(int *out, const char *value)
+int git_config_parse_bool(int *out, const char *value)
 {
 	/* A missing value means true */
 	if (value == NULL) {
@@ -301,7 +301,7 @@ int git_config_get_mapped(git_config *cfg, const char *name, git_cvar_map *maps,
 			case GIT_CVAR_TRUE: {
 				int bool_val;
 
-				if (parse_bool(&bool_val, value) == 0 && 
+				if (git_config_parse_bool(&bool_val, value) == 0 && 
 					bool_val == (int)m->cvar_type) {
 					*out = m->map_value;
 					return 0;
@@ -372,7 +372,7 @@ int git_config_get_bool(git_config *cfg, const char *name, int *out)
 	if (ret < 0)
 		return ret;
 
-	if (parse_bool(out, value) == 0)
+	if (git_config_parse_bool(out, value) == 0)
 		return 0;
 
 	if (parse_int32(out, value) == 0) {
diff --git a/src/config.h b/src/config.h
index 59d1d9a..c337a7a 100644
--- a/src/config.h
+++ b/src/config.h
@@ -25,4 +25,6 @@ struct git_config {
 extern int git_config_find_global_r(git_buf *global_config_path);
 extern int git_config_find_system_r(git_buf *system_config_path);
 
+extern int git_config_parse_bool(int *out, const char *bool_string);
+
 #endif
diff --git a/src/config_file.c b/src/config_file.c
index 077e2c0..60d4c56 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -192,6 +192,9 @@ static int file_foreach(git_config_file *backend, int (*fn)(const char *, const 
 	cvar_t *var;
 	const char *key;
 
+	if (!b->values)
+		return 0;
+
 	GIT_HASHTABLE_FOREACH(b->values, key, var,
 		do {
 			if (fn(key, var->value, data) < 0)
diff --git a/src/config_file.h b/src/config_file.h
new file mode 100644
index 0000000..0080b57
--- /dev/null
+++ b/src/config_file.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_config_file_h__
+#define INCLUDE_config_file_h__
+
+#include "git2/config.h"
+
+GIT_INLINE(int) git_config_file_open(git_config_file *cfg)
+{
+	return cfg->open(cfg);
+}
+
+GIT_INLINE(void) git_config_file_free(git_config_file *cfg)
+{
+	cfg->free(cfg);
+}
+
+GIT_INLINE(int) git_config_file_foreach(
+	git_config_file *cfg,
+	int (*fn)(const char *key, const char *value, void *data),
+	void *data)
+{
+	return cfg->foreach(cfg, fn, data);
+}
+
+#endif
+
diff --git a/src/iterator.c b/src/iterator.c
index aa73d31..3a3be17 100644
--- a/src/iterator.c
+++ b/src/iterator.c
@@ -9,6 +9,7 @@
 #include "tree.h"
 #include "ignore.h"
 #include "buffer.h"
+#include "git2/submodule.h"
 
 typedef struct tree_iterator_frame tree_iterator_frame;
 struct tree_iterator_frame {
@@ -424,13 +425,24 @@ static int workdir_iterator__update_entry(workdir_iterator *wi)
 		return 0; /* if error, ignore it and ignore file */
 
 	/* detect submodules */
-	if (S_ISDIR(wi->entry.mode) &&
-		git_path_contains(&wi->path, DOT_GIT) == true)
-	{
-		size_t len = strlen(wi->entry.path);
-		assert(wi->entry.path[len - 1] == '/');
-		wi->entry.path[len - 1] = '\0';
-		wi->entry.mode = S_IFGITLINK;
+	if (S_ISDIR(wi->entry.mode)) {
+		bool is_submodule = git_path_contains(&wi->path, DOT_GIT);
+
+		/* if there is no .git, still check submodules data */
+		if (!is_submodule) {
+			int res = git_submodule_lookup(NULL, wi->repo, wi->entry.path);
+			is_submodule = (res == 0);
+			if (res == GIT_ENOTFOUND)
+				giterr_clear();
+		}
+
+		/* if submodule, mark as GITLINK and remove trailing slash */
+		if (is_submodule) {
+			size_t len = strlen(wi->entry.path);
+			assert(wi->entry.path[len - 1] == '/');
+			wi->entry.path[len - 1] = '\0';
+			wi->entry.mode = S_IFGITLINK;
+		}
 	}
 
 	return 0;
@@ -489,7 +501,9 @@ int git_iterator_advance_into_directory(
 	workdir_iterator *wi = (workdir_iterator *)iter;
 
 	if (iter->type == GIT_ITERATOR_WORKDIR &&
-		wi->entry.path && S_ISDIR(wi->entry.mode))
+		wi->entry.path &&
+		S_ISDIR(wi->entry.mode) &&
+		!S_ISGITLINK(wi->entry.mode))
 	{
 		if (workdir_iterator__expand_dir(wi) < 0)
 			/* if error loading or if empty, skip the directory. */
diff --git a/src/repository.c b/src/repository.c
index 45bedcb..4e0f9d4 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -64,6 +64,7 @@ void git_repository_free(git_repository *repo)
 	git_cache_free(&repo->objects);
 	git_repository__refcache_free(&repo->references);
 	git_attr_cache_flush(repo);
+	git_submodule_config_free(repo);
 
 	git__free(repo->path_repository);
 	git__free(repo->workdir);
diff --git a/src/repository.h b/src/repository.h
index b5dcc13..6586bb4 100644
--- a/src/repository.h
+++ b/src/repository.h
@@ -83,6 +83,7 @@ struct git_repository {
 	git_cache objects;
 	git_refcache references;
 	git_attr_cache attrcache;
+	git_hashtable *submodules;
 
 	char *path_repository;
 	char *workdir;
@@ -120,4 +121,9 @@ int git_repository_index__weakptr(git_index **out, git_repository *repo);
 int git_repository__cvar(int *out, git_repository *repo, git_cvar_cached cvar);
 void git_repository__cvar_cache_clear(git_repository *repo);
 
+/*
+ * Submodule cache
+ */
+extern void git_submodule_config_free(git_repository *repo);
+
 #endif
diff --git a/src/submodule.c b/src/submodule.c
new file mode 100644
index 0000000..4feefa1
--- /dev/null
+++ b/src/submodule.c
@@ -0,0 +1,384 @@
+/*
+ * Copyright (C) 2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "common.h"
+#include "git2/config.h"
+#include "git2/types.h"
+#include "git2/repository.h"
+#include "git2/index.h"
+#include "git2/submodule.h"
+#include "buffer.h"
+#include "hashtable.h"
+#include "vector.h"
+#include "posix.h"
+#include "config_file.h"
+#include "config.h"
+#include "repository.h"
+
+static const char *sm_update_values[] = {
+	"checkout",
+	"rebase",
+	"merge",
+	NULL
+};
+
+static const char *sm_ignore_values[] = {
+	"all",
+	"dirty",
+	"untracked",
+	"none",
+	NULL
+};
+
+static int lookup_enum(const char **values, const char *str)
+{
+	int i;
+	for (i = 0; values[i]; ++i)
+		if (strcasecmp(str, values[i]) == 0)
+			return i;
+	return -1;
+}
+
+static uint32_t strhash_no_trailing_slash(const void *key, int hash_id)
+{
+	static uint32_t hash_seeds[GIT_HASHTABLE_HASHES] = {
+		0x01010101,
+		0x12345678,
+		0xFEDCBA98
+	};
+
+	size_t key_len = key ? strlen((const char *)key) : 0;
+	if (key_len > 0 && ((const char *)key)[key_len - 1] == '/')
+		key_len--;
+
+	return git__hash(key, (int)key_len, hash_seeds[hash_id]);
+}
+
+static int strcmp_no_trailing_slash(const void *a, const void *b)
+{
+	const char *astr = (const char *)a;
+	const char *bstr = (const char *)b;
+	size_t alen = a ? strlen(astr) : 0;
+	size_t blen = b ? strlen(bstr) : 0;
+	int cmp;
+
+	if (alen > 0 && astr[alen - 1] == '/')
+		alen--;
+	if (blen > 0 && bstr[blen - 1] == '/')
+		blen--;
+
+	cmp = strncmp(astr, bstr, min(alen, blen));
+	if (cmp == 0)
+		cmp = (alen < blen) ? -1 : (alen > blen) ? 1 : 0;
+
+	return cmp;
+}
+
+static git_submodule *submodule_alloc(const char *name)
+{
+	git_submodule *sm = git__calloc(1, sizeof(git_submodule));
+	if (sm == NULL)
+		return sm;
+
+	sm->path = sm->name = git__strdup(name);
+	if (!sm->name) {
+		git__free(sm);
+		return NULL;
+	}
+
+	return sm;
+}
+
+static void submodule_release(git_submodule *sm, int decr)
+{
+	if (!sm)
+		return;
+
+	sm->refcount -= decr;
+
+	if (sm->refcount == 0) {
+		if (sm->name != sm->path)
+			git__free(sm->path);
+		git__free(sm->name);
+		git__free(sm->url);
+		git__free(sm);
+	}
+}
+
+static int submodule_from_entry(
+	git_hashtable *smcfg, git_index_entry *entry)
+{
+	git_submodule *sm;
+	void *old_sm;
+
+	sm = git_hashtable_lookup(smcfg, entry->path);
+	if (!sm)
+		sm = submodule_alloc(entry->path);
+
+	git_oid_cpy(&sm->oid, &entry->oid);
+
+	if (strcmp(sm->path, entry->path) != 0) {
+		if (sm->path != sm->name) {
+			git__free(sm->path);
+			sm->path = sm->name;
+		}
+		sm->path = git__strdup(entry->path);
+		if (!sm->path)
+			goto fail;
+	}
+
+	if (git_hashtable_insert2(smcfg, sm->path, sm, &old_sm) < 0)
+		goto fail;
+	sm->refcount++;
+
+	if (old_sm && ((git_submodule *)old_sm) != sm) {
+		/* TODO: log warning about multiple entrys for same submodule path */
+		submodule_release(old_sm, 1);
+	}
+
+	return 0;
+
+fail:
+	submodule_release(sm, 0);
+	return -1;
+}
+
+static int submodule_from_config(
+	const char *key, const char *value, void *data)
+{
+	git_hashtable *smcfg = data;
+	const char *namestart;
+	const char *property;
+	git_buf name = GIT_BUF_INIT;
+	git_submodule *sm;
+	void *old_sm = NULL;
+	bool is_path;
+
+	if (git__prefixcmp(key, "submodule.") != 0)
+		return 0;
+
+	namestart = key + strlen("submodule.");
+	property  = strrchr(namestart, '.');
+	if (property == NULL)
+		return 0;
+	property++;
+	is_path = (strcmp(property, "path") == 0);
+
+	if (git_buf_set(&name, namestart, property - namestart - 1) < 0)
+		return -1;
+
+	sm = git_hashtable_lookup(smcfg, name.ptr);
+	if (!sm && is_path)
+		sm = git_hashtable_lookup(smcfg, value);
+	if (!sm)
+		sm = submodule_alloc(name.ptr);
+	if (!sm)
+		goto fail;
+
+	if (strcmp(sm->name, name.ptr) != 0) {
+		assert(sm->path == sm->name);
+		sm->name = git_buf_detach(&name);
+		if (git_hashtable_insert2(smcfg, sm->name, sm, &old_sm) < 0)
+			goto fail;
+		sm->refcount++;
+	}
+	else if (is_path && strcmp(sm->path, value) != 0) {
+		assert(sm->path == sm->name);
+		if ((sm->path = git__strdup(value)) == NULL ||
+			git_hashtable_insert2(smcfg, sm->path, sm, &old_sm) < 0)
+			goto fail;
+		sm->refcount++;
+	}
+
+	if (old_sm && ((git_submodule *)old_sm) != sm) {
+		/* TODO: log entry about multiple submodules with same path */
+		submodule_release(old_sm, 1);
+	}
+
+	if (is_path)
+		return 0;
+
+	/* copy other properties into submodule entry */
+	if (strcmp(property, "url") == 0) {
+		if (sm->url) {
+			git__free(sm->url);
+			sm->url = NULL;
+		}
+		if ((sm->url = git__strdup(value)) == NULL)
+			goto fail;
+	}
+	else if (strcmp(property, "update") == 0) {
+		int val = lookup_enum(sm_update_values, value);
+		if (val < 0) {
+			giterr_set(GITERR_INVALID,
+				"Invalid value for submodule update property: '%s'", value);
+			goto fail;
+		}
+		sm->update = (git_submodule_update_t)val;
+	}
+	else if (strcmp(property, "fetchRecurseSubmodules") == 0) {
+		if (git_config_parse_bool(&sm->fetch_recurse, value) < 0)
+			goto fail;
+	}
+	else if (strcmp(property, "ignore") == 0) {
+		int val = lookup_enum(sm_ignore_values, value);
+		if (val < 0) {
+			giterr_set(GITERR_INVALID,
+				"Invalid value for submodule ignore property: '%s'", value);
+			goto fail;
+		}
+		sm->ignore = (git_submodule_ignore_t)val;
+	}
+	/* ignore other unknown submodule properties */
+
+	return 0;
+
+fail:
+	submodule_release(sm, 0);
+	git_buf_free(&name);
+	return -1;
+}
+
+static int load_submodule_config(git_repository *repo)
+{
+	int error;
+	git_index *index;
+	unsigned int i, max_i;
+	git_oid gitmodules_oid;
+	git_hashtable *smcfg;
+	struct git_config_file *mods = NULL;
+
+	if (repo->submodules)
+		return 0;
+
+	/* submodule data is kept in a hashtable with each submodule stored
+	 * under both its name and its path.  These are usually the same, but
+	 * that is not guaranteed.
+	 */
+	smcfg = git_hashtable_alloc(
+		4, strhash_no_trailing_slash, strcmp_no_trailing_slash);
+	GITERR_CHECK_ALLOC(smcfg);
+
+	/* scan index for gitmodules (and .gitmodules entry) */
+	if ((error = git_repository_index(&index, repo)) < 0)
+		goto cleanup;
+	memset(&gitmodules_oid, 0, sizeof(gitmodules_oid));
+	max_i = git_index_entrycount(index);
+
+	for (i = 0; i < max_i; i++) {
+		git_index_entry *entry = git_index_get(index, i);
+		if (S_ISGITLINK(entry->mode)) {
+			if ((error = submodule_from_entry(smcfg, entry)) < 0)
+				goto cleanup;
+		}
+		else if (strcmp(entry->path, ".gitmodules") == 0)
+			git_oid_cpy(&gitmodules_oid, &entry->oid);
+	}
+
+	/* load .gitmodules from workdir if it exists */
+	if (git_repository_workdir(repo) != NULL) {
+		/* look in workdir for .gitmodules */
+		git_buf path = GIT_BUF_INIT;
+		if (!git_buf_joinpath(
+				&path, git_repository_workdir(repo), ".gitmodules") &&
+			git_path_isfile(path.ptr))
+		{
+			if (!(error = git_config_file__ondisk(&mods, path.ptr)))
+				error = git_config_file_open(mods);
+		}
+		git_buf_free(&path);
+	}
+
+	/* load .gitmodules from object cache if not in workdir */
+	if (!error && mods == NULL && !git_oid_iszero(&gitmodules_oid)) {
+		/* TODO: is it worth loading gitmodules from object cache? */
+	}
+
+	/* process .gitmodules info */
+	if (!error && mods != NULL)
+		error = git_config_file_foreach(mods, submodule_from_config, smcfg);
+
+	/* store submodule config in repo */
+	if (!error)
+		repo->submodules = smcfg;
+
+cleanup:
+	if (mods != NULL)
+		git_config_file_free(mods);
+	if (error)
+		git_hashtable_free(smcfg);
+	return error;
+}
+
+void git_submodule_config_free(git_repository *repo)
+{
+	git_hashtable *smcfg = repo->submodules;
+	git_submodule *sm;
+
+	repo->submodules = NULL;
+
+	if (smcfg == NULL)
+		return;
+
+	GIT_HASHTABLE_FOREACH_VALUE(smcfg, sm, { submodule_release(sm,1); });
+	git_hashtable_free(smcfg);
+}
+
+static int submodule_cmp(const void *a, const void *b)
+{
+	return strcmp(((git_submodule *)a)->name, ((git_submodule *)b)->name);
+}
+
+int git_submodule_foreach(
+	git_repository *repo,
+	int (*callback)(const char *name, void *payload),
+	void *payload)
+{
+	int error;
+	git_submodule *sm;
+	git_vector seen = GIT_VECTOR_INIT;
+	seen._cmp = submodule_cmp;
+
+	if ((error = load_submodule_config(repo)) < 0)
+		return error;
+
+	GIT_HASHTABLE_FOREACH_VALUE(
+		repo->submodules, sm, {
+			/* usually the following will not come into play */
+			if (sm->refcount > 1) {
+				if (git_vector_bsearch(&seen, sm) != GIT_ENOTFOUND)
+					continue;
+				if ((error = git_vector_insert(&seen, sm)) < 0)
+					break;
+			}
+
+			if ((error = callback(sm->name, payload)) < 0)
+				break;
+		});
+
+	git_vector_free(&seen);
+
+	return error;
+}
+
+int git_submodule_lookup(
+	git_submodule **sm_ptr, /* NULL allowed if user only wants to test */
+	git_repository *repo,
+	const char *name)       /* trailing slash is allowed */
+{
+	git_submodule *sm;
+
+	if (load_submodule_config(repo) < 0)
+		return -1;
+
+	sm = git_hashtable_lookup(repo->submodules, name);
+
+	if (sm_ptr)
+		*sm_ptr = sm;
+
+	return sm ? 0 : GIT_ENOTFOUND;
+}
diff --git a/tests-clar/status/submodules.c b/tests-clar/status/submodules.c
index 9fd4f0d..10caba1 100644
--- a/tests-clar/status/submodules.c
+++ b/tests-clar/status/submodules.c
@@ -28,6 +28,20 @@ void test_status_submodules__cleanup(void)
 	cl_git_sandbox_cleanup();
 }
 
+void test_status_submodules__api(void)
+{
+	git_submodule *sm;
+
+	cl_assert(git_submodule_lookup(NULL, g_repo, "nonexistent") == GIT_ENOTFOUND);
+
+	cl_assert(git_submodule_lookup(NULL, g_repo, "modified") == GIT_ENOTFOUND);
+
+	cl_git_pass(git_submodule_lookup(&sm, g_repo, "testrepo"));
+	cl_assert(sm != NULL);
+	cl_assert_equal_s("testrepo", sm->name);
+	cl_assert_equal_s("testrepo", sm->path);
+}
+
 static int
 cb_status__submodule_count(const char *p, unsigned int s, void *payload)
 {
@@ -79,7 +93,7 @@ cb_status__match(const char *p, unsigned int s, void *payload)
 {
 	volatile int *index = (int *)payload;
 
-	cl_assert_strequal(expected_files[*index], p);
+	cl_assert_equal_s(expected_files[*index], p);
 	cl_assert(expected_status[*index] == s);
 	(*index)++;