Merge remote-tracking branch 'origin/master'

1 files changed, 46 insertions, 18 deletions

diff --git a/openssl/src/hash.rs b/openssl/src/hash.rs
index 726ebe9c..dd4d136c 100644
--- a/openssl/src/hash.rs
+++ b/openssl/src/hash.rs
@@ -1,22 +1,44 @@
-use std::io::prelude::*;
+use ffi;
+use std::fmt;
 use std::io;
+use std::io::prelude::*;
 use std::ops::{Deref, DerefMut};
-use std::fmt;
-use ffi;
 
-#[cfg(ossl110)]
-use ffi::{EVP_MD_CTX_free, EVP_MD_CTX_new};
-#[cfg(any(ossl101, ossl102))]
-use ffi::{EVP_MD_CTX_create as EVP_MD_CTX_new, EVP_MD_CTX_destroy as EVP_MD_CTX_free};
-
-use {cvt, cvt_p};
 use error::ErrorStack;
+use nid::Nid;
+use {cvt, cvt_p};
+
+cfg_if! {
+    if #[cfg(ossl110)] {
+        use ffi::{EVP_MD_CTX_free, EVP_MD_CTX_new};
+    } else {
+        use ffi::{EVP_MD_CTX_create as EVP_MD_CTX_new, EVP_MD_CTX_destroy as EVP_MD_CTX_free};
+    }
+}
 
 #[derive(Copy, Clone)]
 pub struct MessageDigest(*const ffi::EVP_MD);
 
 impl MessageDigest {
-    pub unsafe fn from_ptr(x: *const ffi::EVP_MD) -> Self { MessageDigest(x) }
+    pub unsafe fn from_ptr(x: *const ffi::EVP_MD) -> Self {
+        MessageDigest(x)
+    }
+
+    /// Returns the `MessageDigest` corresponding to an `Nid`.
+    ///
+    /// This corresponds to [`EVP_get_digestbynid`].
+    ///
+    /// [`EVP_get_digestbynid`]: https://www.openssl.org/docs/man1.1.0/crypto/EVP_DigestInit.html
+    pub fn from_nid(type_: Nid) -> Option<MessageDigest> {
+        unsafe {
+            let ptr = ffi::EVP_get_digestbynid(type_.as_raw());
+            if ptr.is_null() {
+                None
+            } else {
+                Some(MessageDigest(ptr))
+            }
+        }
+    }
 
     pub fn md5() -> MessageDigest {
         unsafe { MessageDigest(ffi::EVP_md5()) }
@@ -229,8 +251,8 @@ impl Drop for Hasher {
 /// store the digest data.
 #[derive(Copy)]
 pub struct DigestBytes {
-    buf: [u8; ffi::EVP_MAX_MD_SIZE as usize],
-    len: usize,
+    pub(crate) buf: [u8; ffi::EVP_MAX_MD_SIZE as usize],
+    pub(crate) len: usize,
 }
 
 impl Clone for DigestBytes {
@@ -382,12 +404,10 @@ mod tests {
 
     #[test]
     fn test_sha256() {
-        let tests = [
-            (
-                "616263",
-                "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad",
-            ),
-        ];
+        let tests = [(
+            "616263",
+            "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad",
+        )];
 
         for test in tests.iter() {
             hash_test(MessageDigest::sha256(), test);
@@ -402,4 +422,12 @@ mod tests {
             hash_test(MessageDigest::ripemd160(), test);
         }
     }
+
+    #[test]
+    fn from_nid() {
+        assert_eq!(
+            MessageDigest::from_nid(Nid::SHA256).unwrap().as_ptr(),
+            MessageDigest::sha256().as_ptr()
+        );
+    }
 }