openpgp: Detect ASCII-Armored data and decode.

  - Add a basic check to the PacketParserBuilder to see if the message
    could be a binary OpenPGP message.  If not, push an ASCII-Armor
    decoder.

1 files changed, 23 insertions, 1 deletions

diff --git a/openpgp/src/parse/packet_parser_builder.rs b/openpgp/src/parse/packet_parser_builder.rs
index 2f927291..73c20d8a 100644
--- a/openpgp/src/parse/packet_parser_builder.rs
+++ b/openpgp/src/parse/packet_parser_builder.rs
@@ -14,6 +14,7 @@ use parse::PacketParserState;
 use parse::PacketParserSettings;
 use parse::ParserResult;
 use parse::Cookie;
+use armor;
 
 /// A builder for configuring a `PacketParser`.
 ///
@@ -118,12 +119,33 @@ impl<'a> PacketParserBuilder<'a> {
     /// # return Ok(ppr);
     /// # }
     /// ```
-    pub fn finalize(self)
+    pub fn finalize(mut self)
         -> Result<PacketParserResult<'a>>
         where Self: 'a
     {
         let state = PacketParserState::new(self.settings);
 
+        // If the first byte does not have the high-bit set, it is
+        // definitely not a binary OpenPGP message.  Since an
+        // ASCII-armor message never has a high-bit set, there is a
+        // good chance that the message is armored.
+        //
+        // This heuristic doesn't work if the message is
+        // ASCII-armored, but the armored data is preceded by
+        // non-ASCII UTF-8, which sets the high bit.  In such cases we
+        // will fail to push an armor decoder.
+        let armored = {
+            let data = self.bio.data(1)?;
+            data.len() > 0 && ((data[0] as i8) > 0)
+        };
+
+        if armored {
+            self.bio = Box::new(BufferedReaderGeneric::with_cookie(
+                armor::Reader::from_buffered_reader(self.bio, None),
+                None,
+                Default::default()));
+        }
+
         // Parse the first packet.
         match PacketParser::parse(Box::new(self.bio), state, vec![ 0 ])? {
             ParserResult::Success(mut pp) => {