[PATCH 02/18] crypto: add _notmuch_crypto_decrypt wrapper function

[Daniel Kahn Gillmor <dkg@fifthhorseman.net>]

We will use this centralized function to consolidate the awkward
behavior around different gmime versions.

It's only invoked from two places: mime-node.c's
node_decrypt_and_verify() and lib/index.cc's
_index_encrypted_mime_part().

However, those two places have some markedly distinct logic, so the
interface for this _notmuch_crypto_decrypt function is going to get a
little bit clunky.  It's worthwhile, though, for the sake of keeping
these #if directives reasonably well-contained.
---
 lib/index.cc  |  8 ++------
 mime-node.c   |  8 ++------
 util/crypto.c | 18 ++++++++++++++++++
 util/crypto.h |  7 +++++--
 4 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/lib/index.cc b/lib/index.cc
index 6e684f5f..19d03456 100644
--- a/lib/index.cc
+++ b/lib/index.cc
@@ -530,9 +530,9 @@ _index_encrypted_mime_part (notmuch_message_t *message,
 
     notmuch = _notmuch_message_database (message);
 
+    GMimeCryptoContext* crypto_ctx = NULL;
 #if (GMIME_MAJOR_VERSION < 3)
     {
-	GMimeCryptoContext* crypto_ctx = NULL;
 	const char *protocol = NULL;
 	protocol = g_mime_content_type_get_parameter (content_type, "protocol");
 	status = _notmuch_crypto_get_gmime_ctx_for_protocol (&(indexopts->crypto),
@@ -546,13 +546,9 @@ _index_encrypted_mime_part (notmuch_message_t *message,
 					      "property (%d)\n", status);
 	    return;
 	}
-	clear = g_mime_multipart_encrypted_decrypt(encrypted_data, crypto_ctx,
-						   NULL, &err);
     }
-#else
-    clear = g_mime_multipart_encrypted_decrypt(encrypted_data, GMIME_DECRYPT_NONE, NULL,
-					       NULL, &err);
 #endif
+    clear = _notmuch_crypto_decrypt (crypto_ctx, encrypted_data, NULL, &err);
     if (err) {
 	_notmuch_database_log (notmuch, "Failed to decrypt during indexing. (%d:%d) [%s]\n",
 			       err->domain, err->code, err->message);
diff --git a/mime-node.c b/mime-node.c
index 28326e03..7f116531 100644
--- a/mime-node.c
+++ b/mime-node.c
@@ -199,12 +199,8 @@ node_decrypt_and_verify (mime_node_t *node, GMimeObject *part,
     GMimeMultipartEncrypted *encrypteddata = GMIME_MULTIPART_ENCRYPTED (part);
 
     node->decrypt_attempted = true;
-    node->decrypted_child = g_mime_multipart_encrypted_decrypt
-#if (GMIME_MAJOR_VERSION < 3)
-	(encrypteddata, cryptoctx, &decrypt_result, &err);
-#else
-        (encrypteddata, GMIME_DECRYPT_NONE, NULL, &decrypt_result, &err);
-#endif
+    if (! node->decrypted_child)
+	node->decrypted_child = _notmuch_crypto_decrypt (cryptoctx, encrypteddata, &decrypt_result, &err);
     if (! node->decrypted_child) {
 	fprintf (stderr, "Failed to decrypt part: %s\n",
 		 err ? err->message : "no error explanation given");
diff --git a/util/crypto.c b/util/crypto.c
index 5c84282e..087536ec 100644
--- a/util/crypto.c
+++ b/util/crypto.c
@@ -138,3 +138,21 @@ void _notmuch_crypto_cleanup (unused(_notmuch_crypto_t *crypto))
 {
 }
 #endif
+
+GMimeObject *
+_notmuch_crypto_decrypt (g_mime_3_unused(GMimeCryptoContext* crypto_ctx),
+			 GMimeMultipartEncrypted *part,
+			 GMimeDecryptResult **decrypt_result,
+			 GError **err)
+{
+    GMimeObject *ret = NULL;
+
+#if (GMIME_MAJOR_VERSION < 3)
+    ret = g_mime_multipart_encrypted_decrypt(part, crypto_ctx,
+					     decrypt_result, err);
+#else
+    ret = g_mime_multipart_encrypted_decrypt(part, GMIME_DECRYPT_NONE, NULL,
+					     decrypt_result, err);
+#endif
+    return ret;
+}
diff --git a/util/crypto.h b/util/crypto.h
index 1ff0297d..d68634f3 100644
--- a/util/crypto.h
+++ b/util/crypto.h
@@ -2,10 +2,8 @@
 #define _CRYPTO_H
 
 #include <stdbool.h>
-#if (GMIME_MAJOR_VERSION < 3)
 #include "gmime-extra.h"
 #include "notmuch.h"
-#endif
 
 typedef struct _notmuch_crypto {
     bool verify;
@@ -17,6 +15,11 @@ typedef struct _notmuch_crypto {
 #endif
 } _notmuch_crypto_t;
 
+GMimeObject *
+_notmuch_crypto_decrypt (GMimeCryptoContext* crypto_ctx,
+			 GMimeMultipartEncrypted *part,
+			 GMimeDecryptResult **decrypt_result,
+			 GError **err);
 
 #if (GMIME_MAJOR_VERSION < 3)
 notmuch_status_t
-- 
2.14.2