1 files changed, 395 insertions, 0 deletions

diff --git a/src/libgit2/transaction.c b/src/libgit2/transaction.c
new file mode 100644
index 000000000..ccffa9984
--- /dev/null
+++ b/src/libgit2/transaction.c
@@ -0,0 +1,395 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * 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 "transaction.h"
+
+#include "repository.h"
+#include "strmap.h"
+#include "refdb.h"
+#include "pool.h"
+#include "reflog.h"
+#include "signature.h"
+#include "config.h"
+
+#include "git2/transaction.h"
+#include "git2/signature.h"
+#include "git2/sys/refs.h"
+#include "git2/sys/refdb_backend.h"
+
+typedef enum {
+	TRANSACTION_NONE,
+	TRANSACTION_REFS,
+	TRANSACTION_CONFIG
+} transaction_t;
+
+typedef struct {
+	const char *name;
+	void *payload;
+
+	git_reference_t ref_type;
+	union {
+		git_oid id;
+		char *symbolic;
+	} target;
+	git_reflog *reflog;
+
+	const char *message;
+	git_signature *sig;
+
+	unsigned int committed :1,
+		remove :1;
+} transaction_node;
+
+struct git_transaction {
+	transaction_t type;
+	git_repository *repo;
+	git_refdb *db;
+	git_config *cfg;
+
+	git_strmap *locks;
+	git_pool pool;
+};
+
+int git_transaction_config_new(git_transaction **out, git_config *cfg)
+{
+	git_transaction *tx;
+
+	GIT_ASSERT_ARG(out);
+	GIT_ASSERT_ARG(cfg);
+
+	tx = git__calloc(1, sizeof(git_transaction));
+	GIT_ERROR_CHECK_ALLOC(tx);
+
+	tx->type = TRANSACTION_CONFIG;
+	tx->cfg = cfg;
+	*out = tx;
+	return 0;
+}
+
+int git_transaction_new(git_transaction **out, git_repository *repo)
+{
+	int error;
+	git_pool pool;
+	git_transaction *tx = NULL;
+
+	GIT_ASSERT_ARG(out);
+	GIT_ASSERT_ARG(repo);
+
+	if ((error = git_pool_init(&pool, 1)) < 0)
+		goto on_error;
+
+	tx = git_pool_mallocz(&pool, sizeof(git_transaction));
+	if (!tx) {
+		error = -1;
+		goto on_error;
+	}
+
+	if ((error = git_strmap_new(&tx->locks)) < 0) {
+		error = -1;
+		goto on_error;
+	}
+
+	if ((error = git_repository_refdb(&tx->db, repo)) < 0)
+		goto on_error;
+
+	tx->type = TRANSACTION_REFS;
+	memcpy(&tx->pool, &pool, sizeof(git_pool));
+	tx->repo = repo;
+	*out = tx;
+	return 0;
+
+on_error:
+	git_pool_clear(&pool);
+	return error;
+}
+
+int git_transaction_lock_ref(git_transaction *tx, const char *refname)
+{
+	int error;
+	transaction_node *node;
+
+	GIT_ASSERT_ARG(tx);
+	GIT_ASSERT_ARG(refname);
+
+	node = git_pool_mallocz(&tx->pool, sizeof(transaction_node));
+	GIT_ERROR_CHECK_ALLOC(node);
+
+	node->name = git_pool_strdup(&tx->pool, refname);
+	GIT_ERROR_CHECK_ALLOC(node->name);
+
+	if ((error = git_refdb_lock(&node->payload, tx->db, refname)) < 0)
+		return error;
+
+	if ((error = git_strmap_set(tx->locks, node->name, node)) < 0)
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	git_refdb_unlock(tx->db, node->payload, false, false, NULL, NULL, NULL);
+
+	return error;
+}
+
+static int find_locked(transaction_node **out, git_transaction *tx, const char *refname)
+{
+	transaction_node *node;
+
+	if ((node = git_strmap_get(tx->locks, refname)) == NULL) {
+		git_error_set(GIT_ERROR_REFERENCE, "the specified reference is not locked");
+		return GIT_ENOTFOUND;
+	}
+
+	*out = node;
+	return 0;
+}
+
+static int copy_common(transaction_node *node, git_transaction *tx, const git_signature *sig, const char *msg)
+{
+	if (sig && git_signature__pdup(&node->sig, sig, &tx->pool) < 0)
+		return -1;
+
+	if (!node->sig) {
+		git_signature *tmp;
+		int error;
+
+		if (git_reference__log_signature(&tmp, tx->repo) < 0)
+			return -1;
+
+		/* make sure the sig we use is in our pool */
+		error = git_signature__pdup(&node->sig, tmp, &tx->pool);
+		git_signature_free(tmp);
+		if (error < 0)
+			return error;
+	}
+
+	if (msg) {
+		node->message = git_pool_strdup(&tx->pool, msg);
+		GIT_ERROR_CHECK_ALLOC(node->message);
+	}
+
+	return 0;
+}
+
+int git_transaction_set_target(git_transaction *tx, const char *refname, const git_oid *target, const git_signature *sig, const char *msg)
+{
+	int error;
+	transaction_node *node;
+
+	GIT_ASSERT_ARG(tx);
+	GIT_ASSERT_ARG(refname);
+	GIT_ASSERT_ARG(target);
+
+	if ((error = find_locked(&node, tx, refname)) < 0)
+		return error;
+
+	if ((error = copy_common(node, tx, sig, msg)) < 0)
+		return error;
+
+	git_oid_cpy(&node->target.id, target);
+	node->ref_type = GIT_REFERENCE_DIRECT;
+
+	return 0;
+}
+
+int git_transaction_set_symbolic_target(git_transaction *tx, const char *refname, const char *target, const git_signature *sig, const char *msg)
+{
+	int error;
+	transaction_node *node;
+
+	GIT_ASSERT_ARG(tx);
+	GIT_ASSERT_ARG(refname);
+	GIT_ASSERT_ARG(target);
+
+	if ((error = find_locked(&node, tx, refname)) < 0)
+		return error;
+
+	if ((error = copy_common(node, tx, sig, msg)) < 0)
+		return error;
+
+	node->target.symbolic = git_pool_strdup(&tx->pool, target);
+	GIT_ERROR_CHECK_ALLOC(node->target.symbolic);
+	node->ref_type = GIT_REFERENCE_SYMBOLIC;
+
+	return 0;
+}
+
+int git_transaction_remove(git_transaction *tx, const char *refname)
+{
+	int error;
+	transaction_node *node;
+
+	if ((error = find_locked(&node, tx, refname)) < 0)
+		return error;
+
+	node->remove = true;
+	node->ref_type = GIT_REFERENCE_DIRECT; /* the id will be ignored */
+
+	return 0;
+}
+
+static int dup_reflog(git_reflog **out, const git_reflog *in, git_pool *pool)
+{
+	git_reflog *reflog;
+	git_reflog_entry *entries;
+	size_t len, i;
+
+	reflog = git_pool_mallocz(pool, sizeof(git_reflog));
+	GIT_ERROR_CHECK_ALLOC(reflog);
+
+	reflog->ref_name = git_pool_strdup(pool, in->ref_name);
+	GIT_ERROR_CHECK_ALLOC(reflog->ref_name);
+
+	len = in->entries.length;
+	reflog->entries.length = len;
+	reflog->entries.contents = git_pool_mallocz(pool, len * sizeof(void *));
+	GIT_ERROR_CHECK_ALLOC(reflog->entries.contents);
+
+	entries = git_pool_mallocz(pool, len * sizeof(git_reflog_entry));
+	GIT_ERROR_CHECK_ALLOC(entries);
+
+	for (i = 0; i < len; i++) {
+		const git_reflog_entry *src;
+		git_reflog_entry *tgt;
+
+		tgt = &entries[i];
+		reflog->entries.contents[i] = tgt;
+
+		src = git_vector_get(&in->entries, i);
+		git_oid_cpy(&tgt->oid_old, &src->oid_old);
+		git_oid_cpy(&tgt->oid_cur, &src->oid_cur);
+
+		tgt->msg = git_pool_strdup(pool, src->msg);
+		GIT_ERROR_CHECK_ALLOC(tgt->msg);
+
+		if (git_signature__pdup(&tgt->committer, src->committer, pool) < 0)
+			return -1;
+	}
+
+
+	*out = reflog;
+	return 0;
+}
+
+int git_transaction_set_reflog(git_transaction *tx, const char *refname, const git_reflog *reflog)
+{
+	int error;
+	transaction_node *node;
+
+	GIT_ASSERT_ARG(tx);
+	GIT_ASSERT_ARG(refname);
+	GIT_ASSERT_ARG(reflog);
+
+	if ((error = find_locked(&node, tx, refname)) < 0)
+		return error;
+
+	if ((error = dup_reflog(&node->reflog, reflog, &tx->pool)) < 0)
+		return error;
+
+	return 0;
+}
+
+static int update_target(git_refdb *db, transaction_node *node)
+{
+	git_reference *ref;
+	int error, update_reflog;
+
+	if (node->ref_type == GIT_REFERENCE_DIRECT) {
+		ref = git_reference__alloc(node->name, &node->target.id, NULL);
+	} else if (node->ref_type == GIT_REFERENCE_SYMBOLIC) {
+		ref = git_reference__alloc_symbolic(node->name, node->target.symbolic);
+	} else {
+		abort();
+	}
+
+	GIT_ERROR_CHECK_ALLOC(ref);
+	update_reflog = node->reflog == NULL;
+
+	if (node->remove) {
+		error =  git_refdb_unlock(db, node->payload, 2, false, ref, NULL, NULL);
+	} else if (node->ref_type == GIT_REFERENCE_DIRECT) {
+		error = git_refdb_unlock(db, node->payload, true, update_reflog, ref, node->sig, node->message);
+	} else if (node->ref_type == GIT_REFERENCE_SYMBOLIC) {
+		error = git_refdb_unlock(db, node->payload, true, update_reflog, ref, node->sig, node->message);
+	} else {
+		abort();
+	}
+
+	git_reference_free(ref);
+	node->committed = true;
+
+	return error;
+}
+
+int git_transaction_commit(git_transaction *tx)
+{
+	transaction_node *node;
+	int error = 0;
+
+	GIT_ASSERT_ARG(tx);
+
+	if (tx->type == TRANSACTION_CONFIG) {
+		error = git_config_unlock(tx->cfg, true);
+		tx->cfg = NULL;
+
+		return error;
+	}
+
+	git_strmap_foreach_value(tx->locks, node, {
+		if (node->reflog) {
+			if ((error = tx->db->backend->reflog_write(tx->db->backend, node->reflog)) < 0)
+				return error;
+		}
+
+		if (node->ref_type == GIT_REFERENCE_INVALID) {
+			/* ref was locked but not modified */
+			if ((error = git_refdb_unlock(tx->db, node->payload, false, false, NULL, NULL, NULL)) < 0) {
+				return error;
+			}
+			node->committed = true;
+		} else {
+			if ((error = update_target(tx->db, node)) < 0)
+				return error;
+		}
+	});
+
+	return 0;
+}
+
+void git_transaction_free(git_transaction *tx)
+{
+	transaction_node *node;
+	git_pool pool;
+
+	if (!tx)
+		return;
+
+	if (tx->type == TRANSACTION_CONFIG) {
+		if (tx->cfg) {
+			git_config_unlock(tx->cfg, false);
+			git_config_free(tx->cfg);
+		}
+
+		git__free(tx);
+		return;
+	}
+
+	/* start by unlocking the ones we've left hanging, if any */
+	git_strmap_foreach_value(tx->locks, node, {
+		if (node->committed)
+			continue;
+
+		git_refdb_unlock(tx->db, node->payload, false, false, NULL, NULL, NULL);
+	});
+
+	git_refdb_free(tx->db);
+	git_strmap_free(tx->locks);
+
+	/* tx is inside the pool, so we need to extract the data */
+	memcpy(&pool, &tx->pool, sizeof(git_pool));
+	git_pool_clear(&pool);
+}