core: Support reading the archive to decrypt/verify directly from a file

* src/engine-gpg.c (add_file_name_arg_or_data): New.
(gpg_decrypt): Use add_file_name_arg_or_data instead of add_data for the
ciphertext.
(gpg_verify): Use add_file_name_arg_or_data instead of add_data for the
signature and the signed text.

* tests/run-decrypt.c (show_usage): New option --direct-file-io.
(main): Parse new option. If option is given, then don't open input
file, create simple data object instead of data object from stream and
set input file name on input data.
* tests/run-verify.c (show_usage): New option --direct-file-io.
(main): Parse new option. If option is given, then don't open input
files, create simple data objects instead of data objects from stream
and set input file names on input data objects.
--

This change makes it possible to tell gpg (and gpgtar) to read the
input (i.e. the signed/encrypted data or the signature or the created
archive) directly from the files with given file names instead of from
streams piped through GpgME's Data IO.

GnuPG-bug-id: 6530

1 files changed, 7 insertions, 3 deletions

diff --git a/doc/gpgme.texi b/doc/gpgme.texi
index cf0525fc..fb604f30 100644
--- a/doc/gpgme.texi
+++ b/doc/gpgme.texi
@@ -5592,8 +5592,9 @@ An error code describing the reason why the key was found invalid.
 
 @deftypefun gpgme_error_t gpgme_op_decrypt (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{cipher}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_decrypt} decrypts the ciphertext in the
-data object @var{cipher} and stores it into the data object
-@var{plain}.
+data object @var{cipher} or, if a file name is set on the data object,
+the ciphertext stored in the corresponding file.  The decrypted
+ciphertext is stored into the data object @var{plain}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 ciphertext could be decrypted successfully, @code{GPG_ERR_INV_VALUE}
@@ -5806,7 +5807,10 @@ detached signature, then the signed text should be provided in
 Otherwise, if @var{sig} is a normal (or cleartext) signature,
 @var{signed_text} should be a null pointer and @var{plain} should be a
 writable data object that will contain the plaintext after successful
-verification.
+verification.  If a file name is set on the data object @var{sig} (or
+on the data object @var{signed_text}), then the data of the signature
+(resp. the data of the signed text) is not read from the data object
+but from the file with the given file name.
 
 The results of the individual signature verifications can be retrieved
 with @code{gpgme_op_verify_result}.