Merge #1335

1335:  fix(runtime-c-api) Change mutability of `memory` for `const` in `wasmer_memory_data_length` r=Hywan a=Hywan

This PR changes mutability of `memory` for `const` in `wasmer_memory_data_length` to be more consistent regarding the returned value of `wasmer_instance_context_memory`.

Fixes #1314. 
Fixes wasmerio/docs.wasmer.io#43.

Co-authored-by: Ivan Enderlin <ivan.enderlin@hoa-project.net>
Co-authored-by: Ivan Enderlin <ivan.enderlin@wanadoo.fr>

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## **[Unreleased]**
 
+- [#1335](https://github.com/wasmerio/wasmer/pull/1335) Change mutability of `memory` to `const` in `wasmer_memory_data_length` in the C API
 - [#1329](https://github.com/wasmerio/wasmer/pull/1329) New numbers and strings instructions for WIT
 - [#1332](https://github.com/wasmerio/wasmer/pull/1332) Add option to `CompilerConfig` to force compiler IR verification off even when `debug_assertions` are enabled. This can be used to make debug builds faster, which may be important if you're creating a library that wraps Wasmer and depend on the speed of debug builds.
 - [#1320](https://github.com/wasmerio/wasmer/pull/1320) Change `custom_sections` field in `ModuleInfo` to be more standards compliant by allowing multiple custom sections with the same name. To get the old behavior with the new API, you can add `.last().unwrap()` to accesses. For example, `module_info.custom_sections["custom_section_name"].last().unwrap()`.

lib/runtime-c-api/src/memory.rs

@@ -198,7 +198,7 @@ pub extern "C" fn wasmer_memory_data(memory: *const wasmer_memory_t) -> *mut u8
 /// ```
 #[allow(clippy::cast_ptr_alignment)]
 #[no_mangle]
-pub extern "C" fn wasmer_memory_data_length(memory: *mut wasmer_memory_t) -> u32 {
+pub extern "C" fn wasmer_memory_data_length(memory: *const wasmer_memory_t) -> u32 {
     if memory.is_null() {
         return 0;
     }

lib/runtime-c-api/wasmer.h

@@ -1171,7 +1171,7 @@ uint8_t *wasmer_memory_data(const wasmer_memory_t *memory);
  * uint32_t memory_data_length = wasmer_memory_data_length(memory);
  * ```
  */
-uint32_t wasmer_memory_data_length(wasmer_memory_t *memory);
+uint32_t wasmer_memory_data_length(const wasmer_memory_t *memory);
 
 /**
  * Frees memory for the given `wasmer_memory_t`.

lib/runtime-c-api/wasmer.hh

@@ -964,7 +964,7 @@ uint8_t *wasmer_memory_data(const wasmer_memory_t *memory);
 /// ```c
 /// uint32_t memory_data_length = wasmer_memory_data_length(memory);
 /// ```
-uint32_t wasmer_memory_data_length(wasmer_memory_t *memory);
+uint32_t wasmer_memory_data_length(const wasmer_memory_t *memory);
 
 /// Frees memory for the given `wasmer_memory_t`.
 ///