skip automatic indentation inside comments

This fixes broken indentation due to
e.g. `wasi:io/streams#output-stream.blocking-write-and-flush`, which has a
doc comment that contains curly brackets.

This isn't generally a problem for Rust, which uses `rustfmt` if available, but
leads to headaches for C if `clang-format` isn't handy.

Signed-off-by: Joel Dice <[email protected]>

crates/core/src/source.rs

@@ -37,36 +37,46 @@ impl Files {
 pub struct Source {
     s: String,
     indent: usize,
+    in_line_comment: bool,
 }
 
 impl Source {
     pub fn append_src(&mut self, src: &Source) {
         self.s.push_str(&src.s);
         self.indent += src.indent;
+        self.in_line_comment = src.in_line_comment;
     }
 
     pub fn push_str(&mut self, src: &str) {
         let lines = src.lines().collect::<Vec<_>>();
         for (i, line) in lines.iter().enumerate() {
             let trimmed = line.trim();
-            if trimmed.starts_with('}') && self.s.ends_with("  ") {
-                self.s.pop();
-                self.s.pop();
+            if trimmed.starts_with("//") {
+                self.in_line_comment = true;
+            }
+
+            if !self.in_line_comment {
+                if trimmed.starts_with('}') && self.s.ends_with("  ") {
+                    self.s.pop();
+                    self.s.pop();
+                }
             }
             self.s.push_str(if lines.len() == 1 {
                 line
             } else {
                 line.trim_start()
             });
-            if trimmed.ends_with('{') {
-                self.indent += 1;
-            }
-            if trimmed.starts_with('}') {
-                // Note that a `saturating_sub` is used here to prevent a panic
-                // here in the case of invalid code being generated in debug
-                // mode. It's typically easier to debug those issues through
-                // looking at the source code rather than getting a panic.
-                self.indent = self.indent.saturating_sub(1);
+            if !self.in_line_comment {
+                if trimmed.ends_with('{') {
+                    self.indent += 1;
+                }
+                if trimmed.starts_with('}') {
+                    // Note that a `saturating_sub` is used here to prevent a panic
+                    // here in the case of invalid code being generated in debug
+                    // mode. It's typically easier to debug those issues through
+                    // looking at the source code rather than getting a panic.
+                    self.indent = self.indent.saturating_sub(1);
+                }
             }
             if i != lines.len() - 1 || src.ends_with('\n') {
                 self.newline();
@@ -83,6 +93,7 @@ impl Source {
     }
 
     fn newline(&mut self) {
+        self.in_line_comment = false;
         self.s.push('\n');
         for _ in 0..self.indent {
             self.s.push_str("  ");

crates/go/src/interface.rs

@@ -1073,7 +1073,6 @@ impl<'a> wit_bindgen_core::InterfaceGenerator<'a> for InterfaceGenerator<'a> {
                 self.preamble
                     .push_str(&format!("// typedef struct {c_typedef_target} "));
                 self.preamble.push_str("{");
-                self.preamble.deindent(1);
                 self.preamble.push_str("\n");
                 self.preamble.push_str("//  int32_t __handle; \n");
                 self.preamble.push_str("// ");