Wiggle: tweaks to internal interfaces (#1469)

* [wiggle]: wiggle-generate internal interface for Names simplified

im using it in other libraries where I don't want to construct a
wiggle_generate::Config just to use the ctx_type out of it.

* wiggle: define_func can get trait name as argument

this flexibility needed for some customization over in lucet

crates/wiggle/generate/src/funcs.rs

@@ -5,7 +5,11 @@ use crate::lifetimes::anon_lifetime;
 use crate::module_trait::passed_by_reference;
 use crate::names::Names;
 
-pub fn define_func(names: &Names, func: &witx::InterfaceFunc) -> TokenStream {
+pub fn define_func(
+    names: &Names,
+    func: &witx::InterfaceFunc,
+    trait_name: TokenStream,
+) -> TokenStream {
     let funcname = func.name.as_str();
 
     let ident = names.func(&func.name);
@@ -166,7 +170,7 @@ pub fn define_func(names: &Names, func: &witx::InterfaceFunc) -> TokenStream {
         {
             log::trace!(#trace_fmt, #(#args),*);
         }
-        let #trait_bindings  = match ctx.#ident(#(#trait_args),*) {
+        let #trait_bindings  = match #trait_name::#ident(ctx, #(#trait_args),*) {
             Ok(#trait_bindings) => { #trait_rets },
             Err(e) => { #ret_err },
         };

crates/wiggle/generate/src/lib.rs

@@ -15,13 +15,18 @@ pub use names::Names;
 pub use types::define_datatype;
 
 pub fn generate(doc: &witx::Document, config: &Config) -> TokenStream {
-    let names = Names::new(config); // TODO parse the names from the invocation of the macro, or from a file?
+    // TODO at some point config should grow more ability to configure name
+    // overrides.
+    let names = Names::new(&config.ctx.name);
 
     let types = doc.typenames().map(|t| define_datatype(&names, &t));
 
     let modules = doc.modules().map(|module| {
         let modname = names.module(&module.name);
-        let fs = module.funcs().map(|f| define_func(&names, &f));
+        let trait_name = names.trait_name(&module.name);
+        let fs = module
+            .funcs()
+            .map(|f| define_func(&names, &f, quote!(#trait_name)));
         let modtrait = define_module_trait(&names, &module);
         let ctx_type = names.ctx_type();
         quote!(

crates/wiggle/generate/src/names.rs

@@ -4,21 +4,19 @@ use quote::{format_ident, quote};
 use witx::{AtomType, BuiltinType, Id, TypeRef};
 
 use crate::lifetimes::LifetimeExt;
-use crate::Config;
 
-#[derive(Debug, Clone)]
 pub struct Names {
-    config: Config,
+    ctx_type: Ident,
 }
 
 impl Names {
-    pub fn new(config: &Config) -> Names {
+    pub fn new(ctx_type: &Ident) -> Names {
         Names {
-            config: config.clone(),
+            ctx_type: ctx_type.clone(),
         }
     }
     pub fn ctx_type(&self) -> Ident {
-        self.config.ctx.name.clone()
+        self.ctx_type.clone()
     }
     pub fn type_(&self, id: &Id) -> TokenStream {
         let ident = format_ident!("{}", id.as_str().to_camel_case());