Added submodule API and use in status

When processing status for a newly checked out repo, it is
possible that there will be submodules that have not yet been
initialized.  The only way to distinguish these from untracked
directories is to have some knowledge of submodules.  This
commit adds a new submodule API which, given a name or path,
can determine if it appears to be a submodule and can give
information about the submodule.

1 files changed, 384 insertions, 0 deletions

diff --git a/src/submodule.c b/src/submodule.c
new file mode 100644
index 000000000..4feefa1e9
--- /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;
+}