transaction: add documentation

include/git2/transaction.h

@@ -10,16 +10,102 @@
 #include "common.h"
 GIT_BEGIN_DECL
 
+/**
+ * Create a new transaction object
+ *
+ * This does not lock anything, but sets up the transaction object to
+ * know from which repository to lock.
+ *
+ * @param out the resulting transaction
+ * @param repo the repository in which to lock
+ * @return 0 or an error code
+ */
 GIT_EXTERN(int) git_transaction_new(git_transaction **out, git_repository *repo);
+
+/**
+ * Lock a reference
+ *
+ * Lock the specified reference. This is the first step to updating a
+ * reference.
+ *
+ * @param tx the transaction
+ * @param refname the reference to lock
+ * @return 0 or an error message
+ */
 GIT_EXTERN(int) git_transaction_lock(git_transaction *tx, const char *refname);
+
+/**
+ * Set the target of a reference
+ *
+ * Set the target of the specified reference. This reference must be
+ * locked.
+ *
+ * @param tx the transaction
+ * @param refname reference to update
+ * @param target target to set the reference to
+ * @param sig signature to use in the reflog; pass NULL to read the identity from the config
+ * @param msg message to use in the reflog
+ * @return 0, GIT_ENOTFOUND if the reference is not among the locked ones, or an error code
+ */
 GIT_EXTERN(int) git_transaction_set_target(git_transaction *tx, const char *refname, const git_oid *target, const git_signature *sig, const char *msg);
 
+/**
+ * Set the target of a reference
+ *
+ * Set the target of the specified reference. This reference must be
+ * locked.
+ *
+ * @param tx the transaction
+ * @param refname reference to update
+ * @param target target to set the reference to
+ * @param sig signature to use in the reflog; pass NULL to read the identity from the config
+ * @param msg message to use in the reflog
+ * @return 0, GIT_ENOTFOUND if the reference is not among the locked ones, or an error code
+ */
 GIT_EXTERN(int) git_transaction_set_symbolic_target(git_transaction *tx, const char *refname, const char *target, const git_signature *sig, const char *msg);
+
+/**
+ * Set the reflog of a reference
+ *
+ * Set the specified reference's reflog. If this is combined with
+ * setting the target, that update won't be written to the reflog.
+ *
+ * @param tx the transaction
+ * @param refname the reference whose reflog to set
+ * @param reflog the reflog as it should be written out
+ * @return 0, GIT_ENOTFOUND if the reference is not among the locked ones, or an error code
+ */
 GIT_EXTERN(int) git_transaction_set_reflog(git_transaction *tx, const char *refname, const git_reflog *reflog);
-GIT_EXTERN(int) git_transaction_commit(git_transaction *tx);
-GIT_EXTERN(void) git_transaction_free(git_transaction *tx);
+
+/**
+ * Remove a reference
+ *
+ * @param tx the transaction
+ * @param refname the reference to remove
+ * @return 0, GIT_ENOTFOUND if the reference is not among the locked ones, or an error code
+ */
 GIT_EXTERN(int) git_transaction_remove(git_transaction *tx, const char *refname);
 
+/**
+ * Commit the changes from the transaction
+ *
+ * Perform the changes that have been queued. The updates will be made
+ * one by one, and the first failure will stop the processing.
+ *
+ * @param tx the transaction
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_transaction_commit(git_transaction *tx);
+
+/**
+ * Free the resources allocated by this transaction
+ *
+ * If any references remain locked, they will be unlocked without any
+ * changes made to them.
+ *
+ * @param tx the transaction
+ */
+GIT_EXTERN(void) git_transaction_free(git_transaction *tx);
 
 GIT_END_DECL
 #endif