Daniel Kahn Gillmor <dkg@fifthhorseman.net> writes:
> -static GMimeCryptoContext*
> -create_gpg_context (_notmuch_crypto_t *crypto)
> +static notmuch_status_t
> +get_gpg_context (_notmuch_crypto_t *crypto, GMimeCryptoContext **ctx)

I was a littled puzzled by this renaming. I guess it's fine, it just
creates a bit more diff noise.
>  /* Create a PKCS7 context (GMime 2.6) */
> -static notmuch_crypto_context_t *
> -create_pkcs7_context (notmuch_crypto_t *crypto)
> +static notmuch_status_t 
> +create_pkcs7_context (_notmuch_crypto_t *crypto, GMimeCryptoContext **ctx)

Especially since you only renamed the gpg version. Or did I miss
something?
> +notmuch_status_t
> +_notmuch_crypto_get_gmime_ctx_for_protocol (_notmuch_crypto_t *crypto,
> +					    const char *protocol,
> +					    GMimeCryptoContext **ctx)
>  {
> -    GMimeCryptoContext *cryptoctx = NULL;
> -    size_t i;
> -
> -    if (! protocol) {
> -	fprintf (stderr, "Cryptographic protocol is empty.\n");
> -	return cryptoctx;
> -    }
> +    if (! protocol)
> +	return NOTMUCH_STATUS_MALFORMED_CRYPTO_PROTOCOL;
>  
>      /* As per RFC 1847 section 2.1: "the [protocol] value token is
>       * comprised of the type and sub-type tokens of the Content-Type".
> @@ -112,15 +112,12 @@ _notmuch_crypto_get_gmime_context (_notmuch_crypto_t *crypto, const char *protoc
>       * parameter names as defined in this document are
>       * case-insensitive."  Thus, we use strcasecmp for the protocol.
>       */
> -    for (i = 0; i < ARRAY_SIZE (protocols); i++) {
> +    for (size_t i = 0; i < ARRAY_SIZE (protocols); i++) {

I forget whether we are using C99 for loop variable declarations.  I
like them myself. If someone figures out the answer, maybe they can
update devel/STYLE.

d