don't panic on UTF8 error (#15)

* don't panic on UTF8 error
* Add missing dyn for trait objects
* Clean up error handling on UTF-8 decoding
* import RedisError

Author: gkorland

examples/data_type.rs

@@ -2,7 +2,7 @@
 extern crate redismodule;
 
 use redismodule::native_types::RedisType;
-use redismodule::{Context, NextArg, RedisResult};
+use redismodule::{Context, NextArg, RedisResult, RedisError};
 
 #[derive(Debug)]
 struct MyType {

examples/hello_redisearch.rs

@@ -2,7 +2,7 @@
 extern crate redismodule;
 
 use redismodule::redisearch;
-use redismodule::{Context, NextArg, RedisResult};
+use redismodule::{Context, NextArg, RedisResult, RedisError};
 
 fn hello_redisearch(_: &Context, args: Vec<String>) -> RedisResult {
     let mut args = args.into_iter().skip(1);

src/error.rs

@@ -51,7 +51,7 @@ impl error::Error for Error {
         }
     }
 
-    fn cause(&self) -> Option<&error::Error> {
+    fn cause(&self) -> Option<&dyn error::Error> {
         match *self {
             // N.B. Both of these implicitly cast `err` from their concrete
             // types (either `&io::Error` or `&num::ParseIntError`)
@@ -88,7 +88,7 @@ impl<'a> error::Error for GenericError {
         self.message.as_str()
     }
 
-    fn cause(&self) -> Option<&error::Error> {
+    fn cause(&self) -> Option<&dyn error::Error> {
         None
     }
 }

src/macros.rs

@@ -13,16 +13,20 @@ macro_rules! redis_command {
         ) -> c_int {
             let context = Context::new(ctx);
 
-            let args: Vec<String> = unsafe { slice::from_raw_parts(argv, argc as usize) }
-                .into_iter()
-                .map(|a| {
-                    RedisString::from_ptr(*a)
-                        .expect("UTF8 encoding error in handler args")
-                        .to_string()
-                })
-                .collect();
+            let args_decoded: Result<Vec<_>, RedisError> =
+                unsafe { slice::from_raw_parts(argv, argc as usize) }
+                    .into_iter()
+                    .map(|&arg| {
+                        RedisString::from_ptr(arg)
+                            .map(|v| v.to_owned())
+                            .map_err(|_| RedisError::Str("UTF8 encoding error in handler args"))
+                    })
+                    .collect();
+
+            let response = args_decoded
+                .map(|args| $command_handler(&context, args))
+                .unwrap_or_else(|e| Err(e));
 
-            let response = $command_handler(&context, args);
             context.reply(response) as c_int
         }
         /////////////////////