Clean up directory structure (#426)

* Remove unused circular-buffer crate
* Move transports into subdirectory
* Move misc into subdirectory
* Move stores into subdirectory
* Move multiplexers
* Move protocols
* Move libp2p top layer
* Fix Test: skip doctest if secio isn't enabled

protocols/secio/src/error.rs

@@ -0,0 +1,126 @@
+// Copyright 2017 Parity Technologies (UK) Ltd.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+//! Defines the `SecioError` enum that groups all possible errors in SECIO.
+
+use aes_ctr::stream_cipher::LoopError;
+use std::error;
+use std::fmt;
+use std::io::Error as IoError;
+
+/// Error at the SECIO layer communication.
+#[derive(Debug)]
+pub enum SecioError {
+    /// I/O error.
+    IoError(IoError),
+
+    /// Failed to parse one of the handshake protobuf messages.
+    HandshakeParsingFailure,
+
+    /// There is no protocol supported by both the local and remote hosts.
+    NoSupportIntersection(&'static str, String),
+
+    /// Failed to generate nonce.
+    NonceGenerationFailed,
+
+    /// Failed to generate ephemeral key.
+    EphemeralKeyGenerationFailed,
+
+    /// Failed to sign a message with our local private key.
+    SigningFailure,
+
+    /// The signature of the exchange packet doesn't verify the remote public key.
+    SignatureVerificationFailed,
+
+    /// Failed to generate the secret shared key from the ephemeral key.
+    SecretGenerationFailed,
+
+    /// The final check of the handshake failed.
+    NonceVerificationFailed,
+
+    /// Error with block cipher.
+    CipherError(LoopError),
+
+    /// The received frame was of invalid length.
+    FrameTooShort,
+
+    /// The hashes of the message didn't match.
+    HmacNotMatching,
+}
+
+impl error::Error for SecioError {
+    #[inline]
+    fn description(&self) -> &str {
+        match *self {
+            SecioError::IoError(_) => "I/O error",
+            SecioError::HandshakeParsingFailure => {
+                "Failed to parse one of the handshake protobuf messages"
+            }
+            SecioError::NoSupportIntersection(_, _) => {
+                "There is no protocol supported by both the local and remote hosts"
+            }
+            SecioError::NonceGenerationFailed => "Failed to generate nonce",
+            SecioError::EphemeralKeyGenerationFailed => "Failed to generate ephemeral key",
+            SecioError::SigningFailure => "Failed to sign a message with our local private key",
+            SecioError::SignatureVerificationFailed => {
+                "The signature of the exchange packet doesn't verify the remote public key"
+            }
+            SecioError::SecretGenerationFailed => {
+                "Failed to generate the secret shared key from the ephemeral key"
+            }
+            SecioError::NonceVerificationFailed => "The final check of the handshake failed",
+            SecioError::CipherError(_) => "Error while decoding/encoding data",
+            SecioError::FrameTooShort => "The received frame was of invalid length",
+            SecioError::HmacNotMatching => "The hashes of the message didn't match",
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match *self {
+            SecioError::IoError(ref err) => Some(err),
+            // TODO: The type doesn't implement `Error`
+            /*SecioError::CipherError(ref err) => {
+                Some(err)
+            },*/
+            _ => None,
+        }
+    }
+}
+
+impl fmt::Display for SecioError {
+    #[inline]
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(fmt, "{}", error::Error::description(self))
+    }
+}
+
+impl From<LoopError> for SecioError {
+    #[inline]
+    fn from(err: LoopError) -> SecioError {
+        SecioError::CipherError(err)
+    }
+}
+
+impl From<IoError> for SecioError {
+    #[inline]
+    fn from(err: IoError) -> SecioError {
+        SecioError::IoError(err)
+    }
+}