From 6895cde14ab237e07869b47166f41d8df2e251e4 Mon Sep 17 00:00:00 2001
From: Tangent 128 <Tangent128@gmail.com>
Date: Wed, 2 Jan 2019 21:45:44 -0500
Subject: [PATCH] derive EBML errors via custom_error!{}

---
 Cargo.lock  |  7 +++++++
 Cargo.toml  |  1 +
 src/ebml.rs | 48 ++++++++----------------------------------------
 3 files changed, 16 insertions(+), 40 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index e43db3f..4a9358a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -149,6 +149,11 @@ dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "custom_error"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "digest"
 version = "0.8.1"
@@ -1197,6 +1202,7 @@ version = "0.2.0"
 dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "custom_error 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "http 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.12.31 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1265,6 +1271,7 @@ dependencies = [
 "checksum crossbeam-epoch 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "04c9e3102cc2d69cd681412141b390abd55a362afc1540965dad0ad4d34280b4"
 "checksum crossbeam-queue 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7c979cd6cfe72335896575c6b5688da489e420d36a27a0b9eb0c73db574b4a4b"
 "checksum crossbeam-utils 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "f8306fcef4a7b563b76b7dd949ca48f52bc1141aa067d2ea09565f3e2652aa5c"
+"checksum custom_error 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c189751d60563837f66c7ebf87f6a6e4c101e937d54521e88620e89c79b8a2ad"
 "checksum digest 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f3d0c8c8752312f9713efd397ff63acb9f85585afbf179282e720e7704954dd5"
 "checksum dtoa 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "ea57b42383d091c85abcc2706240b94ab2a8fa1fc81c10ff23c4de06e2a90b5e"
 "checksum either 1.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "5527cfe0d098f36e3f8839852688e63c8fff1c90b2b405aef730615f9a7bcf7b"
diff --git a/Cargo.toml b/Cargo.toml
index 8f42920..e6624a0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2018"
 [dependencies]
 bytes = "0.4.12"
 clap = "2.33.0"
+custom_error = "1.3.0"
 futures = "0.1.28"
 http = "0.1.17"
 hyper = "0.12.31"
diff --git a/src/ebml.rs b/src/ebml.rs
index 2136e00..a896ec2 100644
--- a/src/ebml.rs
+++ b/src/ebml.rs
@@ -1,6 +1,5 @@
 use bytes::{BigEndian, ByteOrder, BufMut};
-use std::error::Error as ErrorTrait;
-use std::fmt::{Display, Formatter, Result as FmtResult};
+use custom_error::custom_error;
 use std::io::{Cursor, Error as IoError, ErrorKind, Result as IoResult, Write, Seek, SeekFrom};
 use futures::Async;
 
@@ -8,46 +7,15 @@ pub const EBML_HEAD_ID: u64 = 0x0A45DFA3;
 pub const DOC_TYPE_ID: u64 = 0x0282;
 pub const VOID_ID: u64 = 0x6C;
 
-#[derive(Debug, PartialEq)]
-pub enum EbmlError {
-    CorruptVarint,
-    UnknownElementId,
-    UnknownElementLength,
-    CorruptPayload,
-}
-impl Display for EbmlError {
-    fn fmt(&self, f: &mut Formatter) -> FmtResult {
-        write!(f, "{}", self.description())
-    }
-}
-impl ErrorTrait for EbmlError {
-    fn description(&self) -> &str {
-        match self {
-            &EbmlError::CorruptVarint => "EBML Varint could not be parsed",
-            &EbmlError::UnknownElementId => "EBML element ID was \"unknown\"",
-            &EbmlError::UnknownElementLength => "EBML element length was \"unknown\" for an element not allowing that",
-            &EbmlError::CorruptPayload => "EBML element payload could not be parsed",
-        }
-    }
+custom_error!{pub EbmlError
+    CorruptVarint        = r#"EBML Varint could not be parsed"#,
+    UnknownElementId     = r#"EBML element ID was "unknown"#,
+    UnknownElementLength = r#"EBML element length was "unknown" for an element not allowing that"#,
+    CorruptPayload       = r#"EBML element payload could not be parsed"#,
 }
 
-#[derive(Debug, PartialEq)]
-pub enum WriteError {
-    OutOfRange
-}
-impl Display for WriteError {
-    fn fmt(&self, f: &mut Formatter) -> FmtResult {
-        match self {
-            &WriteError::OutOfRange => write!(f, "EBML Varint out of range")
-        }
-    }
-}
-impl ErrorTrait for WriteError {
-    fn description(&self) -> &str {
-        match self {
-            &WriteError::OutOfRange => "EBML Varint out of range"
-        }
-    }
+custom_error!{pub WriteError
+    OutOfRange = "EBML Varint out of range"
 }
 
 #[derive(Debug, PartialEq)]