ffi: Introduce macro for moving ownership from C.

6 files changed, 54 insertions, 116 deletions

diff --git a/ffi/src/core.rs b/ffi/src/core.rs
index 564f3ae8..b207bdb9 100644
--- a/ffi/src/core.rs
+++ b/ffi/src/core.rs
@@ -181,11 +181,10 @@ pub extern "system" fn sq_context_ephemeral(ctx: Option<&Context>) -> uint8_t {
 /// Consumes `cfg`.  Returns `NULL` on errors. Returns `NULL` on
 /// errors.  If `errp` is not `NULL`, the error is stored there.
 #[no_mangle]
-pub extern "system" fn sq_config_build(cfg: Option<&mut Config>,
+pub extern "system" fn sq_config_build(cfg: *mut Config,
                                        errp: Option<&mut *mut failure::Error>)
                                        -> *mut Context {
-    assert!(cfg.is_some());
-    let cfg = unsafe { Box::from_raw(cfg.unwrap()) };
+    let cfg = ffi_param_move!(cfg);
 
     match cfg.build() {
         Ok(context) =>
diff --git a/ffi/src/lib.rs b/ffi/src/lib.rs
index 3dd0a252..5c813a37 100644
--- a/ffi/src/lib.rs
+++ b/ffi/src/lib.rs
@@ -143,6 +143,22 @@ macro_rules! ffi_free {
 
 /* Parameter handling.  */
 
+/// Transfers ownership from C to Rust.
+///
+/// # Panics
+///
+/// Panics if called with NULL.
+macro_rules! ffi_param_move {
+    ($name:expr) => {{
+        if $name.is_null() {
+            panic!("Parameter {} is NULL", stringify!($name));
+        }
+        unsafe {
+            Box::from_raw($name)
+        }
+    }};
+}
+
 /// Transfers a reference from C to Rust.
 ///
 /// # Panics
diff --git a/ffi/src/openpgp/armor.rs b/ffi/src/openpgp/armor.rs
index 9e6b3611..b3ed8edb 100644
--- a/ffi/src/openpgp/armor.rs
+++ b/ffi/src/openpgp/armor.rs
@@ -189,10 +189,7 @@ pub extern "system" fn sq_armor_reader_kind(reader: *mut Box<Read>)
     // little dance.  We will momentarily take ownership of `reader`,
     // wrapping it in a Box again.  Then, at the end of the function,
     // we will leak it again.
-    assert!(! reader.is_null());
-    let reader = unsafe {
-        Box::from_raw(reader as *mut Box<armor::Reader>)
-    };
+    let reader = ffi_param_move!(reader as *mut Box<armor::Reader>);
     let kind = kind_to_int(reader.kind());
     Box::into_raw(reader);
     kind
@@ -221,16 +218,13 @@ pub extern "system" fn sq_armor_reader_headers(ctx: Option<&mut Context>,
                                                len: Option<&mut size_t>)
                                                -> *mut ArmorHeader {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! reader.is_null());
     let len = ffi_param_ref!(len);
 
     // We need to downcast `reader`.  To do that, we need to do a
     // little dance.  We will momentarily take ownership of `reader`,
     // wrapping it in a Box again.  Then, at the end of the function,
     // we will leak it again.
-    let mut reader = unsafe {
-        Box::from_raw(reader as *mut Box<armor::Reader>)
-    };
+    let mut reader = ffi_param_move!(reader as *mut Box<armor::Reader>);
 
     // We need to be extra careful here in order not to keep ownership
     // of `reader` in case of errors.
diff --git a/ffi/src/openpgp/mod.rs b/ffi/src/openpgp/mod.rs
index cef143af..8123c4fc 100644
--- a/ffi/src/openpgp/mod.rs
+++ b/ffi/src/openpgp/mod.rs
@@ -108,10 +108,7 @@ pub extern "system" fn sq_revocation_status_variant(
     rs: *mut RevocationStatus)
     -> c_int
 {
-    assert!(! rs.is_null());
-    let rs = unsafe {
-        Box::from_raw(rs as *mut RevocationStatus)
-    };
+    let rs = ffi_param_move!(rs as *mut RevocationStatus);
     let variant = revocation_status_to_int(rs.as_ref());
     Box::into_raw(rs);
     variant
@@ -170,9 +167,7 @@ pub extern "system" fn sq_tsk_tpk(tsk: Option<&TSK>)
 #[no_mangle]
 pub extern "system" fn sq_tsk_into_tpk(tsk: *mut TSK)
                                        -> *mut TPK {
-    let tsk = unsafe {
-        Box::from_raw(tsk)
-    };
+    let tsk = ffi_param_move!(tsk);
     box_raw!(tsk.into_tpk())
 }
 
@@ -239,10 +234,8 @@ pub extern "system" fn sq_signature_free(s: *mut Signature) {
 pub extern "system" fn sq_signature_to_packet(s: *mut Signature)
                                               -> *mut Packet
 {
-    assert!(! s.is_null());
-    unsafe {
-        box_raw!(Box::from_raw(s).to_packet())
-    }
+    let s = ffi_param_move!(s);
+    box_raw!(s.to_packet())
 }
 
 /// Returns the value of the `Signature` packet's Issuer subpacket.
@@ -828,10 +821,7 @@ pub extern "system" fn sq_packet_parser_next<'a>
      ppr: Option<&mut *mut PacketParserResult<'a>>)
      -> Status {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! pp.is_null());
-    let pp = unsafe {
-        Box::from_raw(pp)
-    };
+    let pp = ffi_param_move!(pp);
 
     match pp.next() {
         Ok((old_p, new_ppr)) => {
@@ -875,10 +865,7 @@ pub extern "system" fn sq_packet_parser_recurse<'a>
      ppr: Option<&mut *mut PacketParserResult<'a>>)
      -> Status {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! pp.is_null());
-    let pp = unsafe {
-        Box::from_raw(pp)
-    };
+    let pp = ffi_param_move!(pp);
 
     match pp.recurse() {
         Ok((old_p, new_ppr)) => {
@@ -1008,10 +995,7 @@ pub extern "system" fn sq_packet_parser_result_packet_parser<'a>
     (ppr: *mut PacketParserResult<'a>)
     -> *mut PacketParser<'a>
 {
-    assert!(! ppr.is_null());
-    let ppr = unsafe {
-        Box::from_raw(ppr)
-    };
+    let ppr = ffi_param_move!(ppr);
 
     match *ppr {
         PacketParserResult::Some(pp) => box_raw!(pp),
@@ -1039,10 +1023,7 @@ pub extern "system" fn sq_packet_parser_result_eof<'a>
     (ppr: *mut PacketParserResult<'a>)
     -> *mut PacketParserEOF
 {
-    assert!(! ppr.is_null());
-    let ppr = unsafe {
-        Box::from_raw(ppr)
-    };
+    let ppr = ffi_param_move!(ppr);
 
     match *ppr {
         PacketParserResult::Some(_) => {
@@ -1073,10 +1054,7 @@ pub extern "system" fn sq_writer_stack_message
     (writer: *mut Box<Write>)
      -> *mut writer::Stack<'static, Cookie>
 {
-    assert!(!writer.is_null());
-    let writer = unsafe {
-        Box::from_raw(writer)
-    };
+    let writer = ffi_param_move!(writer);
     box_raw!(Message::new(writer))
 }
 
@@ -1127,9 +1105,7 @@ pub extern "system" fn sq_writer_stack_finalize_one
 {
     let ctx = ffi_param_ref!(ctx);
     if !writer.is_null() {
-        let writer = unsafe {
-            Box::from_raw(writer)
-        };
+        let writer = ffi_param_move!(writer);
         maybe_box_raw!(fry!(ctx, writer.finalize_one()))
     } else {
         ptr::null_mut()
@@ -1145,9 +1121,7 @@ pub extern "system" fn sq_writer_stack_finalize
 {
     let ctx = ffi_param_ref!(ctx);
     if !writer.is_null() {
-        let writer = unsafe {
-            Box::from_raw(writer)
-        };
+        let writer = ffi_param_move!(writer);
         fry_status!(ctx, writer.finalize())
     } else {
         Status::Success
@@ -1167,10 +1141,7 @@ pub extern "system" fn sq_arbitrary_writer_new
      -> *mut writer::Stack<'static, Cookie>
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!inner.is_null());
-    let inner = unsafe {
-        Box::from_raw(inner)
-    };
+    let inner = ffi_param_move!(inner);
     fry_box!(ctx, ArbitraryWriter::new(*inner, tag.into()))
 }
 
@@ -1187,10 +1158,7 @@ pub extern "system" fn sq_signer_new
      -> *mut writer::Stack<'static, Cookie>
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!inner.is_null());
-    let inner = unsafe {
-        Box::from_raw(inner)
-    };
+    let inner = ffi_param_move!(inner);
     let signers = ffi_param_ref!(signers);
     let signers = unsafe {
         slice::from_raw_parts(signers, signers_len)
@@ -1207,10 +1175,7 @@ pub extern "system" fn sq_signer_new_detached
      -> *mut writer::Stack<'static, Cookie>
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!inner.is_null());
-    let inner = unsafe {
-        Box::from_raw(inner)
-    };
+    let inner = ffi_param_move!(inner);
     let signers = signers.expect("Signers is NULL");
     let signers = unsafe {
         slice::from_raw_parts(signers, signers_len)
@@ -1229,10 +1194,7 @@ pub extern "system" fn sq_literal_writer_new
      -> *mut writer::Stack<'static, Cookie>
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!inner.is_null());
-    let inner = unsafe {
-        Box::from_raw(inner)
-    };
+    let inner = ffi_param_move!(inner);
     fry_box!(ctx, LiteralWriter::new(*inner,
                                      DataFormat::Binary,
                                      None,
@@ -1257,10 +1219,7 @@ pub extern "system" fn sq_encryptor_new
      -> *mut writer::Stack<'static, Cookie>
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!inner.is_null());
-    let inner = unsafe {
-        Box::from_raw(inner)
-    };
+    let inner = ffi_param_move!(inner);
     let mut passwords_ = Vec::new();
     if passwords_len > 0 {
         let passwords = passwords.expect("Passwords is NULL");
@@ -1646,9 +1605,7 @@ impl DecryptionHelper for DHelper {
                 "Callback did not return a session key".into()).into());
         }
 
-        let secret = unsafe {
-            Box::from_raw(secret)
-        };
+        let secret = ffi_param_move!(secret);
 
         Ok(Some(*secret))
     }
diff --git a/ffi/src/openpgp/tpk.rs b/ffi/src/openpgp/tpk.rs
index 23a11b22..814bac99 100644
--- a/ffi/src/openpgp/tpk.rs
+++ b/ffi/src/openpgp/tpk.rs
@@ -68,8 +68,7 @@ pub extern "system" fn sq_tpk_from_packet_pile(ctx: Option<&mut Context>,
                                                m: *mut PacketPile)
                                                -> *mut TPK {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! m.is_null());
-    let m = unsafe { Box::from_raw(m) };
+    let m = ffi_param_move!(m);
     fry_box!(ctx, TPK::from_packet_pile(*m))
 }
 
@@ -98,8 +97,7 @@ pub extern "system" fn sq_tpk_from_packet_parser(ctx: Option<&mut Context>,
     -> *mut TPK
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! ppr.is_null());
-    let ppr = unsafe { Box::from_raw(ppr) };
+    let ppr = ffi_param_move!(ppr);
 
     fry_box!(ctx, TPK::from_packet_parser(*ppr))
 }
@@ -152,10 +150,8 @@ pub extern "system" fn sq_tpk_merge(ctx: Option<&mut Context>,
                                     other: *mut TPK)
                                     -> *mut TPK {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! tpk.is_null());
-    let tpk = unsafe { Box::from_raw(tpk) };
-    assert!(! other.is_null());
-    let other = unsafe { Box::from_raw(other) };
+    let tpk = ffi_param_move!(tpk);
+    let other = ffi_param_move!(other);
     fry_box!(ctx, tpk.merge(*other))
 }
 
@@ -173,8 +169,7 @@ pub extern "system" fn sq_tpk_merge_packets(ctx: Option<&mut Context>,
                                             packets_len: size_t)
                                             -> *mut TPK {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! tpk.is_null());
-    let tpk = unsafe { Box::from_raw(tpk) };
+    let tpk = ffi_param_move!(tpk);
     let packets = unsafe {
         slice::from_raw_parts_mut(packets, packets_len)
     };
@@ -205,10 +200,7 @@ pub extern "system" fn sq_tpk_fingerprint(tpk: Option<&TPK>)
 #[no_mangle]
 pub extern "system" fn sq_tpk_into_tsk(tpk: *mut TPK)
                                        -> *mut TSK {
-    assert!(!tpk.is_null());
-    let tpk = unsafe {
-        Box::from_raw(tpk)
-    };
+    let tpk = ffi_param_move!(tpk);
     box_raw!(tpk.into_tsk())
 }
 
@@ -352,10 +344,7 @@ pub extern "system" fn sq_tpk_revoke_in_place(ctx: Option<&mut Context>,
     -> *mut TPK
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!tpk.is_null());
-    let tpk = unsafe {
-        Box::from_raw(tpk)
-    };
+    let tpk = ffi_param_move!(tpk);
     let code = int_to_reason_for_revocation(code);
     let reason = if let Some(reason) = reason {
         unsafe {
@@ -413,10 +402,7 @@ pub extern "system" fn sq_tpk_set_expiry(ctx: Option<&mut Context>,
                                          tpk: *mut TPK, expiry: u32)
                                          -> *mut TPK {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!tpk.is_null());
-    let tpk = unsafe {
-        Box::from_raw(tpk)
-    };
+    let tpk = ffi_param_move!(tpk);
 
     fry_box!(ctx, tpk.set_expiry_in_seconds(expiry))
 }
@@ -626,8 +612,7 @@ pub extern "system" fn sq_tpk_builder_set_cipher_suite
 {
     use self::CipherSuite::*;
     let tpkb = ffi_param_ref!(tpkb);
-    assert!(! tpkb.is_null());
-    let tpkb_ = unsafe { Box::from_raw(*tpkb) };
+    let tpkb_ = ffi_param_move!(*tpkb);
     let cs = match cs {
         0 => Cv25519,
         1 => RSA3k,
@@ -644,8 +629,7 @@ pub extern "system" fn sq_tpk_builder_add_userid
     (tpkb: Option<&mut *mut TPKBuilder>, uid: *const c_char)
 {
     let tpkb = ffi_param_ref!(tpkb);
-    assert!(!tpkb.is_null());
-    let tpkb_ = unsafe { Box::from_raw(*tpkb) };
+    let tpkb_ = ffi_param_move!(*tpkb);
     let uid = unsafe { CStr::from_ptr(uid).to_string_lossy().to_string() };
     let tpkb_ = tpkb_.add_userid(uid.as_ref());
     *tpkb = box_raw!(tpkb_);
@@ -657,8 +641,7 @@ pub extern "system" fn sq_tpk_builder_add_signing_subkey
     (tpkb: Option<&mut *mut TPKBuilder>)
 {
     let tpkb = ffi_param_ref!(tpkb);
-    assert!(!tpkb.is_null());
-    let tpkb_ = unsafe { Box::from_raw(*tpkb) };
+    let tpkb_ = ffi_param_move!(*tpkb);
     let tpkb_ = tpkb_.add_signing_subkey();
     *tpkb = box_raw!(tpkb_);
 }
@@ -669,8 +652,7 @@ pub extern "system" fn sq_tpk_builder_add_encryption_subkey
     (tpkb: Option<&mut *mut TPKBuilder>)
 {
     let tpkb = ffi_param_ref!(tpkb);
-    assert!(!tpkb.is_null());
-    let tpkb_ = unsafe { Box::from_raw(*tpkb) };
+    let tpkb_ = ffi_param_move!(*tpkb);
     let tpkb_ = tpkb_.add_encryption_subkey();
     *tpkb = box_raw!(tpkb_);
 }
@@ -681,8 +663,7 @@ pub extern "system" fn sq_tpk_builder_add_certification_subkey
     (tpkb: Option<&mut *mut TPKBuilder>)
 {
     let tpkb = ffi_param_ref!(tpkb);
-    assert!(!tpkb.is_null());
-    let tpkb_ = unsafe { Box::from_raw(*tpkb) };
+    let tpkb_ = ffi_param_move!(*tpkb);
     let tpkb_ = tpkb_.add_certification_subkey();
     *tpkb = box_raw!(tpkb_);
 }
@@ -698,10 +679,9 @@ pub extern "system" fn sq_tpk_builder_generate
     -> Status
 {
     let ctx = ffi_param_ref!(ctx);
-    assert!(!tpkb.is_null());
     let tpk_out = ffi_param_ref!(tpk_out);
     let revocation_out = ffi_param_ref!(revocation_out);
-    let tpkb = unsafe { Box::from_raw(tpkb) };
+    let tpkb = ffi_param_move!(tpkb);
     match tpkb.generate() {
         Ok((tpk, revocation)) => {
             *tpk_out = box_raw!(tpk);
diff --git a/ffi/src/store.rs b/ffi/src/store.rs
index c7a8944d..31e05376 100644
--- a/ffi/src/store.rs
+++ b/ffi/src/store.rs
@@ -302,10 +302,7 @@ pub extern "system" fn sq_store_delete(ctx: Option<&mut Context>,
                                        store: *mut Store)
                                        -> Status {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! store.is_null());
-    let store = unsafe {
-        Box::from_raw(store)
-    };
+    let store = ffi_param_move!(store);
 
     fry_status!(ctx, store.delete())
 }
@@ -383,9 +380,7 @@ pub extern "system" fn sq_key_free(key: *mut Key) {
 #[no_mangle]
 pub extern "system" fn sq_log_free(log: *mut Log) {
     if log.is_null() { return };
-    let log = unsafe {
-        Box::from_raw(log)
-    };
+    let log = ffi_param_move!(log);
     sq_store_free(log.store);
     sq_binding_free(log.binding);
     sq_key_free(log.key);
@@ -490,10 +485,7 @@ pub extern "system" fn sq_binding_delete(ctx: Option<&mut Context>,
                                          binding: *mut Binding)
                                          -> Status {
     let ctx = ffi_param_ref!(ctx);
-    assert!(! binding.is_null());
-    let binding = unsafe {
-        Box::from_raw(binding)
-    };
+    let binding = ffi_param_move!(binding);
 
     fry_status!(ctx, binding.delete())
 }