[shotwell] Remove external hmac_sha1

[Jens Georg <jensgeorg src gnome org>]

commit 0ddee1cb2c13278a5354dd702f2519cef30b005e
Author: Jens Georg <mail jensge org>
Date:   Wed Jun 1 22:19:50 2016 +0200

    Remove external hmac_sha1
    
    Instead of relying on librest leaking the hmac_sha1 symbol, port the
    implementation of librest to Vala
    
    Signed-off-by: Jens Georg <mail jensge org>

 plugins/common/RESTSupport.vala                    |   16 ++++++++++++++++
 .../TumblrPublishing.vala                          |    3 +--
 2 files changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/plugins/common/RESTSupport.vala b/plugins/common/RESTSupport.vala
index 7a12c5f..08e4e15 100644
--- a/plugins/common/RESTSupport.vala
+++ b/plugins/common/RESTSupport.vala
@@ -6,6 +6,22 @@
 
 namespace Publishing.RESTSupport {
 
+// Ported from librest
+// https://git.gnome.org/browse/librest/tree/rest/sha1.c?id=e412da58080eec2e771482e7e4c509b9e71477ff#n38
+
+internal const int SHA1_HMAC_LENGTH = 20;
+
+public string hmac_sha1(string key, string message) {
+    uint8 buffer[SHA1_HMAC_LENGTH];
+    size_t len = SHA1_HMAC_LENGTH;
+
+    var mac = new Hmac (ChecksumType.SHA1, key.data);
+    mac.update (message.data);
+    mac.get_digest (buffer, ref len);
+
+    return Base64.encode (buffer[0:len]);
+}
+
 public abstract class Session {
     private string? endpoint_url = null;
     private Soup.Session soup_session = null;
diff --git a/plugins/shotwell-publishing-extras/TumblrPublishing.vala 
b/plugins/shotwell-publishing-extras/TumblrPublishing.vala
index 6bafb21..0d6fbfb 100644
--- a/plugins/shotwell-publishing-extras/TumblrPublishing.vala
+++ b/plugins/shotwell-publishing-extras/TumblrPublishing.vala
@@ -6,7 +6,6 @@
  */
 
 
-extern string hmac_sha1(string key, string message);
 public class TumblrService : Object, Spit.Pluggable, Spit.Publishing.Service {
    private const string ICON_FILENAME = "tumblr.png";
 
@@ -1105,7 +1104,7 @@ internal class Session : Publishing.RESTSupport.Session {
         debug("signing key = '%s'", signing_key);
 
         // compute the signature
-        string signature = hmac_sha1(signing_key, signature_base_string);
+        string signature = Publishing.RESTSupport.hmac_sha1(signing_key, signature_base_string);
         debug("signature = '%s'", signature);
         signature = Soup.URI.encode(signature, ENCODE_RFC_3986_EXTRA);