Closes #651:

- adds support to select a specific world from a WIT file if
  multiple worlds are specified.

Signed-off-by: Shailesh Vashishth <[email protected]>

Author: vshailesh

src/hyperlight_component_macro/src/lib.rs

@@ -50,6 +50,8 @@ limitations under the License.
 extern crate proc_macro;
 
 use hyperlight_component_util::*;
+use syn::parse::{Parse, ParseStream};
+use syn::{Ident, LitStr, Result, Token};
 
 /// Create host bindings for the wasm component type in the file
 /// passed in (or `$WIT_WORLD`, if nothing is passed in). This will
@@ -63,6 +65,7 @@ use hyperlight_component_util::*;
 /// `instantiate()` method on the component trait that makes
 /// instantiating the sandbox particularly ergonomic in core
 /// Hyperlight.
+
 #[proc_macro]
 pub fn host_bindgen(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let _ = env_logger::try_init();
@@ -79,6 +82,48 @@ pub fn host_bindgen(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     })
 }
 
+#[proc_macro]
+pub fn host_bindgen2(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let _ = env_logger::try_init();
+
+    let parsed_bindgen_input = syn::parse_macro_input!(input as BindgenInputParams);
+
+    eprintln!("WE GET BACK FROM THE PARSING");
+    eprintln!("{:?}", parsed_bindgen_input);
+
+    let path = parsed_bindgen_input.path.unwrap_or_else(|| {
+        let wit_world_env = std::env::var_os("WIT_WORLD");
+
+        if let Some(env) = wit_world_env {
+            std::path::PathBuf::from(env)
+        } else {
+            std::path::PathBuf::new()
+        }
+    });
+
+    let world_name = parsed_bindgen_input.world_name;
+
+    // what do we do, do we disturb the function signature or
+    // put this world_name as an env or a rust static variable.
+    // keeping as a rust static variable seems to be an appropriate
+    // choice. frequently changing the OS env will be stupid
+
+    eprintln!("PATH = {:?} \n WORLD_NAME = {:?}", path.clone().into_os_string(), world_name.clone());
+    
+
+    util::read_world_from_file_1(
+        path.into_os_string(),
+        world_name,
+        |kebab_name, ct: &etypes::Component<'_>| {
+            let decls = emit::run_state(false, false, |s| {
+                rtypes::emit_toplevel(s, &kebab_name, ct);
+                host::emit_toplevel(s, &kebab_name, ct);
+            });
+            util::emit_decls(decls).into()
+        },
+    )
+}
+
 /// Create the hyperlight_guest_init() function (which should be
 /// called in hyperlight_main()) for the wasm component type in the
 /// file passed in (or `$WIT_WORLD`, if nothing is passed in). This
@@ -107,3 +152,46 @@ pub fn guest_bindgen(input: proc_macro::TokenStream) -> proc_macro::TokenStream
         util::emit_decls(decls).into()
     })
 }
+
+#[derive(Debug)]
+struct BindgenInputParams {
+    world_name: Option<String>,
+    path: Option<std::path::PathBuf>,
+}
+
+impl Parse for BindgenInputParams {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let content;
+        syn::braced!(content in input);
+        eprintln!("Content = \n {:?}", content);
+
+        let mut world_name = None;
+        let mut path = None;
+
+        // Parse key-value pairs inside the braces
+        while !content.is_empty() {
+            let key: Ident = content.parse()?;
+            content.parse::<Token![:]>()?;
+
+            match key.to_string().as_str() {
+                "world_name" => {
+                    let value: LitStr = content.parse()?;
+                    world_name = Some(value.value());
+                }
+                "path" => {
+                    let value: LitStr = content.parse()?;
+                    path = Some(std::path::PathBuf::from(value.value()));
+                }
+                _ => {
+                    return Err(syn::Error::new(key.span(), format!("Unknown key: {}", key)));
+                }
+            }
+
+            // Parse optional comma
+            if content.peek(Token![,]) {
+                content.parse::<Token![,]>()?;
+            }
+        }
+        Ok(Self { world_name, path })
+    }
+}

src/hyperlight_component_util/src/component.rs

@@ -149,6 +149,8 @@ pub fn read_component_single_exported_type<'a>(
             _ => {}
         }
     }
+
+    // eprintln!("{:?}",ctx.types.into_iter().nth(n));
     match last_idx {
         None => panic!("no exported type"),
         Some(n) => match ctx.types.into_iter().nth(n) {
@@ -157,3 +159,92 @@ pub fn read_component_single_exported_type<'a>(
         },
     }
 }
+
+pub fn read_component_specific_world_name<'a>(
+    items: impl Iterator<Item = wasmparser::Result<Payload<'a>>>,
+    world_name: String,
+) -> Component<'a> {
+    let mut ctx = Ctx::new(None, false);
+    let mut world_idx = None;
+
+    for x in items {
+        match x {
+            Ok(Version { num, encoding, .. }) => {
+                if encoding != wasmparser::Encoding::Component {
+                    panic!("wasm file is not a component")
+                }
+                if num != 0xd {
+                    panic!("unknown component encoding version 0x{:x}\n", num);
+                }
+            }
+            Ok(ComponentTypeSection(ts)) => {
+                for t in ts {
+                    match t {
+                        Ok(ComponentType::Component(ct)) => {
+                            let ct_ = ctx.elab_component(&ct);
+                            ctx.types.push(Defined::Component(ct_.unwrap()));
+                        }
+                        _ => panic!("non-component type"),
+                    }
+                }
+            }
+            Ok(ComponentExportSection(es)) => {
+                for e in es {
+                    match e {
+                        Err(_) => panic!("invalid export section"),
+                        Ok(ce) => {
+                            if ce.kind == ComponentExternalKind::Type {
+                                ctx.types.push(raw_type_export_type(&ctx, &ce).clone());
+                                match ce.name {
+                                    wasmparser::ComponentExportName(name) => {
+                                        if name.eq_ignore_ascii_case(&world_name) {
+                                            eprintln!("WE GOT IN = {}", name);
+                                            eprintln!("Found matching world: {} (looking for: {})", name, world_name);
+                                            world_idx = Some(ctx.types.len() - 1);
+                                            eprintln!("Found matching world: {} (looking for: {:?})", name, world_idx.clone());
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            Ok(ComponentAliasSection(r#as)) => {
+                for a in r#as {
+                    match a {
+                        Ok(ComponentAlias::InstanceExport {
+                            kind: ComponentExternalKind::Type,
+                            ..
+                        })
+                        | Ok(ComponentAlias::Outer {
+                            kind: ComponentOuterAliasKind::Type,
+                            ..
+                        }) => {
+                            panic!("Component outer type aliases are not supported")
+                        }
+                        // Anything else doesn't affect the index
+                        // space that we are interested in, so we can
+                        // safely ignore
+                        _ => {}
+                    }
+                }
+            }
+
+            // No other component section should be terribly relevant
+            // for us.  We would not generally expect to find them in
+            // a file that just represents a type like this, but it
+            // seems like there are/may be a whole bunch of debugging
+            // custom sections, etc that might show up, so for now
+            // let's just ignore anything.
+            _ => {}
+        }
+    }
+    match world_idx {
+        None => panic!("expected world name not found"),
+        Some(n) => match ctx.types.into_iter().nth(n) {
+            Some(Defined::Component(c)) => c,
+            _ => panic!("final export is not component"),
+        },
+    }
+}

src/hyperlight_component_util/src/util.rs

@@ -50,6 +50,39 @@ pub fn read_wit_type_from_file<R, F: FnMut(String, &etypes::Component) -> R>(
     cb(export.kebab_name.to_string(), ct)
 }
 
+pub fn read_world_from_file_1<R, F: FnMut(String, &etypes::Component) -> R>(
+    filename: impl AsRef<std::ffi::OsStr>,
+    world_name: Option<String>,
+    mut cb: F,
+) -> R {
+    let path = std::path::Path::new(&filename);
+    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    eprintln!("PATH2 = {:?}", path);
+    let manifest_dir = std::path::Path::new(&manifest_dir);
+    let path = manifest_dir.join(path);
+
+    let bytes = std::fs::read(path).unwrap();
+    let i = wasmparser::Parser::new(0).parse_all(&bytes);
+    let ct = crate::component::read_component_specific_world_name(i, world_name.unwrap());
+
+    // because of the two-level encapsulation scheme, we need to look
+    // for the single export of the component type that we just read
+    if !ct.uvars.is_empty()
+        || !ct.imports.is_empty()
+        || !ct.instance.evars.is_empty()
+        || ct.instance.unqualified.exports.len() != 1
+    {
+        panic!("malformed component type container for wit type");
+    };
+    let export = &ct.instance.unqualified.exports[0];
+    use etypes::ExternDesc;
+    let ExternDesc::Component(ct) = &export.desc else {
+        panic!("malformed component type container: does not contain component type");
+    };
+    log::debug!("hcm: considering component type {:?}", ct);
+    cb(export.kebab_name.to_string(), ct)
+}
+
 /// Deal with `$HYPERLIGHT_COMPONENT_MACRO_DEBUG`: if it is present,
 /// save the given token stream (representing the result of
 /// macroexpansion) to the debug file and include that file instead of