capi: use c_int::from(bool) and naked signed integers for returning c_ints

c_int::from(bool) relies on the semantics documented in the Rust
reference so that:

i{32,64,etc}::from(b: bool) will return 0 with b == false and 1 with b
== true.

This change also uses `return {0,1,-1}` without an explicit From::from
for c_int as suggested by clippy. The semantics now require that a
(signed) C integer has a direct representation as a signed Rust one _as
inferred by the compiler_ (ie. i32, i64, ...).

Author: unleashed

src/capi/encoding.rs

@@ -31,13 +31,13 @@ pub unsafe extern "C" fn encoding_encode_buffer(
     let c_slice_dst = if let Some(c_slice_mut) = CSliceMut::new_from_size_ptr(dst, dstlen_ptr) {
         c_slice_mut
     } else {
-        return c_int::from(-1);
+        return -1;
     };
 
     let c_slice_src = if let Some(c_slice) = CSlice::new(src, srclen) {
         c_slice
     } else {
-        return c_int::from(-1);
+        return -1;
     };
 
     let cow = encoding::encode(&c_slice_src);
@@ -46,7 +46,7 @@ pub unsafe extern "C" fn encoding_encode_buffer(
     unsafe { *dstlen_ptr = required_len };
 
     if required_len > c_slice_dst.len() {
-        return c_int::from(-1);
+        return -1;
     }
 
     unsafe {
@@ -55,5 +55,5 @@ pub unsafe extern "C" fn encoding_encode_buffer(
         core::ptr::copy_nonoverlapping(cow.as_ptr(), dst as *mut _, required_len);
     }
 
-    c_int::from(0)
+    0
 }

src/capi/mapping_rule.rs

@@ -83,30 +83,26 @@ pub unsafe extern "C" fn rest_rule_matches(
     path_qs: *const c_char,
 ) -> c_int {
     if rule.is_null() {
-        return c_int::from(-1);
+        return -1;
     }
 
     let method_s = if let Some(c_slice) = CSlice::new(method, 0) {
         c_slice.as_cow()
     } else {
-        return c_int::from(-1);
+        return -1;
     };
     let path_qs = if let Some(c_slice) = CSlice::new(path_qs, 0) {
         c_slice.as_cow()
     } else {
-        return c_int::from(-1);
+        return -1;
     };
 
     let rule = unsafe { std::ptr::read::<RestRule>(rule) };
     let rule = ManuallyDrop::new(rule);
 
     let method = Method::from(method_s.as_ref());
 
-    if rule.matches(&method, path_qs) {
-        c_int::from(1)
-    } else {
-        c_int::from(0)
-    }
+    c_int::from(rule.matches(&method, path_qs))
 }
 
 #[no_mangle]
@@ -117,18 +113,18 @@ pub unsafe extern "C" fn rest_rule_matches_path_n_qs(
     qs: *const c_char,
 ) -> c_int {
     if rule.is_null() {
-        return c_int::from(-1);
+        return -1;
     }
 
     let method_s = if let Some(c_slice) = CSlice::new(method, 0) {
         c_slice.as_cow()
     } else {
-        return c_int::from(-1);
+        return -1;
     };
     let path = if let Some(c_slice) = CSlice::new(path, 0) {
         c_slice.as_cow()
     } else {
-        return c_int::from(-1);
+        return -1;
     };
     let qs = if let Some(c_slice) = CSlice::new(qs, 0) {
         c_slice.as_cow().into()
@@ -141,11 +137,7 @@ pub unsafe extern "C" fn rest_rule_matches_path_n_qs(
 
     let method = Method::from(method_s.as_ref());
 
-    if &method == rule.method() && rule.matches_path_n_qs(path, qs) {
-        c_int::from(1)
-    } else {
-        c_int::from(0)
-    }
+    c_int::from(&method == rule.method() && rule.matches_path_n_qs(path, qs))
 }
 
 #[no_mangle]
@@ -154,27 +146,21 @@ pub unsafe extern "C" fn rest_rule_matches_request_line(
     http_request_line: *const c_char,
 ) -> c_int {
     if rule.is_null() {
-        return c_int::from(-1);
+        return -1;
     }
 
     let http_request_line = if let Some(c_slice) = CSlice::new(http_request_line, 0) {
         c_slice.as_cow()
     } else {
-        return c_int::from(-1);
+        return -1;
     };
 
     let rule = unsafe { std::ptr::read::<RestRule>(rule) };
     let rule = ManuallyDrop::new(rule);
 
     match rule.matches_request_line(http_request_line) {
-        Ok(b) => {
-            if b {
-                c_int::from(1)
-            } else {
-                c_int::from(0)
-            }
-        }
-        Err(_) => c_int::from(-1),
+        Ok(b) => c_int::from(b),
+        Err(_) => -1,
     }
 }