ffi: Improve error handling.

  - Use the new facilities for more functions.

  - Improve documentation.

2 files changed, 23 insertions, 24 deletions

diff --git a/ffi/src/lib.rs b/ffi/src/lib.rs
index 0647c823..ab6ad8f0 100644
--- a/ffi/src/lib.rs
+++ b/ffi/src/lib.rs
@@ -18,7 +18,14 @@
 //! Sequoia objects are opaque objects.  They are created in
 //! constructors, and must be freed when no longer needed.
 //!
-//! Strings must be UTF-8 encoded and zero-terminated.
+//! Pointers handed to Sequoia must not be `NULL`, destructors are
+//! exempt from this rule.  Freeing `NULL` is a nop.
+//!
+//! Enumeration-like values must be in the valid range.
+//!
+//! Strings must be UTF-8 encoded and zero-terminated.  Malformed
+//! characters will be substituted, and the result is likely not what
+//! you expect.
 //!
 //! # Lifetimes
 //!
@@ -427,18 +434,10 @@ pub extern "system" fn sq_keyserver_with_cert(ctx: Option<&mut Context>,
 ///
 /// Returns `NULL` on errors.
 #[no_mangle]
-pub extern "system" fn sq_keyserver_sks_pool(ctx: Option<&Context>) -> *mut KeyServer {
-    if ctx.is_none() {
-        return ptr::null_mut();
-    }
-
-    let ks = KeyServer::sks_pool(&ctx.unwrap().c);
-
-    if let Ok(ks) = ks {
-        Box::into_raw(Box::new(ks))
-    } else {
-        ptr::null_mut()
-    }
+pub extern "system" fn sq_keyserver_sks_pool(ctx: Option<&mut Context>)
+                                             -> *mut KeyServer {
+    let ctx = ctx.expect("Context is NULL");
+    fry_box!(ctx, KeyServer::sks_pool(&ctx.c))
 }
 
 /// Frees a keyserver object.
@@ -456,13 +455,12 @@ pub extern "system" fn sq_keyserver_free(ks: *mut KeyServer) {
 ///
 /// Returns `NULL` on errors.
 #[no_mangle]
-pub extern "system" fn sq_keyserver_get(ks: Option<&mut KeyServer>,
+pub extern "system" fn sq_keyserver_get(ctx: Option<&mut Context>,
+                                        ks: Option<&mut KeyServer>,
                                         id: Option<&KeyID>) -> *mut TPK {
-    if ks.is_none() || id.is_none() {
-        return ptr::null_mut();
-    }
+    let ctx = ctx.expect("Context is NULL");
+    let ks = ks.expect("KeyServer is NULL");
+    let id = id.expect("KeyID is NULL");
 
-    ks.unwrap().get(id.as_ref().unwrap())
-        .map(|id| Box::into_raw(Box::new(id)))
-        .unwrap_or(ptr::null_mut())
+    fry_box!(ctx, ks.get(&id))
 }
diff --git a/ffi/src/sequoia.h b/ffi/src/sequoia.h
index 0a21ef7c..27b6e419 100644
--- a/ffi/src/sequoia.h
+++ b/ffi/src/sequoia.h
@@ -271,7 +271,7 @@ struct sq_keyserver;
 ///
 /// Returns `NULL` on errors.
 /*/
-struct sq_keyserver *sq_keyserver_new (const struct sq_context *ctx,
+struct sq_keyserver *sq_keyserver_new (struct sq_context *ctx,
 				       const char *uri);
 
 /*/
@@ -283,7 +283,7 @@ struct sq_keyserver *sq_keyserver_new (const struct sq_context *ctx,
 ///
 /// Returns `NULL` on errors.
 /*/
-struct sq_keyserver *sq_keyserver_with_cert (const struct sq_context *ctx,
+struct sq_keyserver *sq_keyserver_with_cert (struct sq_context *ctx,
 					     const char *uri,
 					     const uint8_t *cert,
 					     size_t len);
@@ -297,7 +297,7 @@ struct sq_keyserver *sq_keyserver_with_cert (const struct sq_context *ctx,
 ///
 /// Returns `NULL` on errors.
 /*/
-struct sq_keyserver *sq_keyserver_sks_pool (const struct sq_context *ctx);
+struct sq_keyserver *sq_keyserver_sks_pool (struct sq_context *ctx);
 
 /*/
 /// Frees a keyserver object.
@@ -309,7 +309,8 @@ void sq_keyserver_free (struct sq_keyserver *ks);
 ///
 /// Returns `NULL` on errors.
 /*/
-struct sq_tpk *sq_keyserver_get (struct sq_keyserver *ks,
+struct sq_tpk *sq_keyserver_get (struct sq_context *ctx,
+				 struct sq_keyserver *ks,
 				 const struct sq_keyid *id);
 
 #endif