From 96ca40faedfe2c2de988f65873a9baaf9eb7d415 Mon Sep 17 00:00:00 2001
From: Elichai Turkel <elichai.turkel@gmail.com>
Date: Thu, 4 Jul 2019 21:18:36 -0400
Subject: [PATCH] Exposed generic functions to create the Context

---
 src/context.rs | 20 +++++++++++---------
 src/lib.rs     |  4 ++--
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/context.rs b/src/context.rs
index aa35d1e..5dec624 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -7,7 +7,7 @@ use Secp256k1;
 #[cfg(feature = "std")]
 pub use self::std_only::*;
 
-/// A trait for all kinds of Context's that let's you define the exact flags and a function to deallocate memory.
+/// A trait for all kinds of Context's that Lets you define the exact flags and a function to deallocate memory.
 /// * DO NOT * implement it for your own types.
 pub unsafe trait Context {
     /// Flags for the ffi.
@@ -86,7 +86,8 @@ mod std_only {
     }
 
     impl<C: Context> Secp256k1<C> {
-        fn gen_new() -> Secp256k1<C> {
+        /// Lets you create a context in a generic manner(sign/verify/all)
+        pub fn gen_new() -> Secp256k1<C> {
             let buf = vec![0u8; Self::preallocate_size_gen()].into_boxed_slice();
             let ptr = Box::into_raw(buf);
             Secp256k1 {
@@ -148,8 +149,8 @@ unsafe impl<'buf> Context for SignOnlyPreallocated<'buf> {
     const FLAGS: c_uint = ffi::SECP256K1_START_SIGN;
     const DESCRIPTION: &'static str = "signing only";
 
-    fn deallocate(ptr: *mut [u8]) {
-        let _ = ptr;
+    fn deallocate(_ptr: *mut [u8]) {
+        // Allocated by the user
     }
 }
 
@@ -157,8 +158,8 @@ unsafe impl<'buf> Context for VerifyOnlyPreallocated<'buf> {
     const FLAGS: c_uint = ffi::SECP256K1_START_VERIFY;
     const DESCRIPTION: &'static str = "verification only";
 
-    fn deallocate(ptr: *mut [u8]) {
-        let _ = ptr;
+    fn deallocate(_ptr: *mut [u8]) {
+        // Allocated by the user
     }
 }
 
@@ -166,13 +167,14 @@ unsafe impl<'buf> Context for AllPreallocated<'buf> {
     const FLAGS: c_uint = SignOnlyPreallocated::FLAGS | VerifyOnlyPreallocated::FLAGS;
     const DESCRIPTION: &'static str = "all capabilities";
 
-    fn deallocate(ptr: *mut [u8]) {
-        let _ = ptr;
+    fn deallocate(_ptr: *mut [u8]) {
+        // Allocated by the user
     }
 }
 
 impl<'buf, C: Context + 'buf> Secp256k1<C> {
-    fn preallocated_gen_new(buf: &'buf mut [u8]) -> Result<Secp256k1<C>, Error> {
+    /// Lets you create a context with preallocated buffer in a generic manner(sign/verify/all)
+    pub fn preallocated_gen_new(buf: &'buf mut [u8]) -> Result<Secp256k1<C>, Error> {
         if buf.len() < Self::preallocate_size_gen() {
             return Err(Error::NotEnoughMemory);
         }
diff --git a/src/lib.rs b/src/lib.rs
index d82e359..6651bc2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -570,8 +570,8 @@ impl<C: Context> Secp256k1<C> {
         &self.ctx
     }
 
-    /// Uses the ffi `secp256k1_context_preallocated_size` to check the memory size needed for a context
-    pub(crate) fn preallocate_size_gen() -> usize {
+    /// Returns the required memory for a preallocated context buffer in a generic manner(sign/verify/all)
+    pub fn preallocate_size_gen() -> usize {
         unsafe { ffi::secp256k1_context_preallocated_size(C::FLAGS) }
     }