Derive Copy and Clone for ring::signature::Signature.

Derive `Copy` and `Clone` for `Signature`.

Add some utilities for testing `Clone`, `Copy`, `Send`, and `Sync`
and use them to test that `Signature` implements these traits.

Author: briansmith

Cargo.toml

@@ -253,6 +253,7 @@ include = [
     "tests/rsa_pss_sign_tests.txt",
     "tests/rsa_pss_verify_tests.txt",
     "tests/rsa_tests.rs",
+    "tests/signature_tests.rs",
     "third-party/NIST/README.md",
     "third-party/NIST/sha256sums.txt",
     "third-party/NIST/SHAVS/SHA1LongMsg.rsp",

src/signature_impl.rs

@@ -18,6 +18,7 @@
 use ec;
 
 /// A public key signature returned from a signing operation.
+#[derive(Clone, Copy)]
 pub struct Signature {
     value: [u8; MAX_LEN],
     len: usize,

src/test.rs

@@ -126,6 +126,24 @@ use std::string::String;
 use std::vec::Vec;
 use std::io::BufRead;
 
+
+/// `compile_time_assert_clone::<T>();` fails to compile if `T` doesn't
+/// implement `Clone`.
+pub fn compile_time_assert_clone<T: Clone>() {}
+
+/// `compile_time_assert_copy::<T>();` fails to compile if `T` doesn't
+/// implement `Copy`.
+pub fn compile_time_assert_copy<T: Copy>() {}
+
+/// `compile_time_assert_send::<T>();` fails to compile if `T` doesn't
+/// implement `Send`.
+pub fn compile_time_assert_send<T: Send>() {}
+
+/// `compile_time_assert_sync::<T>();` fails to compile if `T` doesn't
+/// implement `Sync`.
+pub fn compile_time_assert_sync<T: Sync>() {}
+
+
 /// A test case. A test case consists of a set of named attributes. Every
 /// attribute in the test case must be consumed exactly once; this helps catch
 /// typos and omissions.

tests/signature_tests.rs

@@ -0,0 +1,12 @@
+extern crate ring;
+
+use ring::signature;
+use ring::test;
+
+#[test]
+fn signature_impl_test() {
+    test::compile_time_assert_clone::<signature::Signature>();
+    test::compile_time_assert_copy::<signature::Signature>();
+    test::compile_time_assert_send::<signature::Signature>();
+    test::compile_time_assert_sync::<signature::Signature>();
+}