Add option for all module raw lines

Provide an option to add a line to every mod generated by bindgen.

Part of google/autocxx#124, though
this is only in fact necessary if we make the changes given in
google/autocxx#1456.

Author: adetaylor

bindgen-tests/tests/expectations/tests/namespace.rs

@@ -1,4 +1,4 @@
-// bindgen-flags: --enable-cxx-namespaces --module-raw-line root::whatever 'pub type whatever_other_thing_t = whatever_int_t;'
+// bindgen-flags: --enable-cxx-namespaces --module-raw-line root::whatever 'pub type whatever_other_thing_t = whatever_int_t;' --every-module-raw-line 'struct PerModStruct;'
 
 void top_level();
 

bindgen-tests/tests/headers/namespace.hpp

@@ -609,6 +609,7 @@ impl CodeGenerator for Module {
                 .namespace_aware_canonical_path(ctx)
                 .join("::")
                 .into_boxed_str();
+
             if let Some(raw_lines) = ctx.options().module_lines.get(&path) {
                 for raw_line in raw_lines {
                     found_any = true;
@@ -617,6 +618,14 @@ impl CodeGenerator for Module {
                     );
                 }
             }
+            // For lines we add to all modules, don't modify `found_any`
+            // since we don't want to generate this module unless there's
+            // other stuff present.
+            result.extend(ctx.options().every_module_raw_lines.iter().map(
+                |raw_line| {
+                    proc_macro2::TokenStream::from_str(raw_line).unwrap()
+                },
+            ));
 
             codegen_self(result, &mut found_any);
         });

bindgen/codegen/mod.rs

@@ -336,6 +336,9 @@ struct BindgenCommand {
     /// Add a raw line of Rust code at the beginning of output.
     #[arg(long)]
     raw_line: Vec<String>,
+    /// Add a raw line of Rust code at the beginning of each module.
+    #[arg(long)]
+    every_module_raw_line: Vec<String>,
     /// Add a RAW_LINE of Rust code to a given module with name MODULE_NAME.
     #[arg(long, number_of_values = 2, value_names = ["MODULE_NAME", "RAW_LINE"])]
     module_raw_line: Vec<String>,
@@ -601,6 +604,7 @@ where
         opaque_type,
         output,
         raw_line,
+        every_module_raw_line,
         module_raw_line,
         rust_target,
         rust_edition,
@@ -907,6 +911,7 @@ where
             block_extern_crate,
             opaque_type,
             raw_line,
+            every_module_raw_line,
             use_core => |b, _| b.use_core(),
             distrust_clang_mangling => |b, _| b.trust_clang_mangling(false),
             conservative_inline_namespaces => |b, _| b.conservative_inline_namespaces(),

bindgen/options/cli.rs

@@ -1161,6 +1161,24 @@ options! {
             }
         },
     },
+    /// The set of raw lines to be prepended to every module of the generated Rust code.
+    every_module_raw_lines: Vec<Box<str>> {
+        methods: {
+            /// Add a line of Rust code at the beginning of each module (i.e.
+            /// C++ namespace) in the generated code. The string is
+            /// passed through without any modification.
+            pub fn every_module_raw_line<T: Into<String>>(mut self, arg: T) -> Self {
+                self.options.every_module_raw_lines.push(arg.into().into_boxed_str());
+                self
+            }
+        },
+        as_args: |every_module_raw_lines, args| {
+            for line in every_module_raw_lines {
+                args.push("--every-module-raw-line".to_owned());
+                args.push(line.clone().into());
+            }
+        },
+    },
     /// The set of raw lines to prepend to different modules.
     module_lines: HashMap<Box<str>, Vec<Box<str>>> {
         methods: {