From af8b16fa1f54494eaec594ddb5212620111c887c Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Tue, 13 Apr 2021 17:32:18 -0600
Subject: correctly handle comments and non-comments

---
 src/makefile/input.rs | 95 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 75 insertions(+), 20 deletions(-)

diff --git a/src/makefile/input.rs b/src/makefile/input.rs
index 0618109..7f49bef 100644
--- a/src/makefile/input.rs
+++ b/src/makefile/input.rs
@@ -144,6 +144,23 @@ impl<T, E: StdError + Send + Sync + 'static, I: Iterator<Item = Result<T, E>>> I
 {
 }
 
+#[derive(Clone, Copy)]
+struct NextLineSettings {
+    escaped_newline_replacement: &'static str,
+    peeking: bool,
+    strip_comments: bool,
+}
+
+impl Default for NextLineSettings {
+    fn default() -> Self {
+        Self {
+            escaped_newline_replacement: " ",
+            peeking: false,
+            strip_comments: true,
+        }
+    }
+}
+
 pub struct MakefileReader<'a, 'parent, R: BufRead> {
     file_name: String,
     pub inference_rules: Vec<InferenceRule>,
@@ -235,7 +252,11 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
     }
 
     fn read_all(&mut self) -> Result<()> {
-        while let Some((line_number, line)) = self.next_line(" ", false) {
+        let topmost = NextLineSettings {
+            escaped_newline_replacement: " ",
+            ..Default::default()
+        };
+        while let Some((line_number, line)) = self.next_line(topmost) {
             let line = line?;
 
             // handle include lines
@@ -383,16 +404,28 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
         Ok(())
     }
 
-    fn next_line(
-        &mut self,
-        escaped_newline_replacement: &'static str,
-        peeking: bool,
-    ) -> Option<(usize, Result<String>)> {
+    fn next_line(&mut self, settings: NextLineSettings) -> Option<(usize, Result<String>)> {
+        lazy_static! {
+            static ref COMMENT: Regex = Regex::new(r"([^\\]|^)#.*$").unwrap();
+        }
+        let escaped_newline_replacement = settings.escaped_newline_replacement;
         if let Some((line_number, line)) = self.pending_line.take() {
-            if peeking {
+            if settings.peeking {
                 self.pending_line = Some((line_number, line.clone()));
             }
-            return Some((line_number, Ok(line.join(escaped_newline_replacement))));
+            let line = line.join(escaped_newline_replacement);
+            let line = if settings.strip_comments {
+                // TODO only do this if we were in don't-strip-comments mode before
+                // TODO deduplicate
+                COMMENT
+                    .replace(&line, "$1")
+                    .replace(r"\#", "#")
+                    .trim_end()
+                    .to_owned()
+            } else {
+                line
+            };
+            return Some((line_number, Ok(line)));
         }
         while let Some((line_number, line)) = self.lines_iter.next() {
             let line = match line {
@@ -400,10 +433,15 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
                 Err(err) => return Some((line_number, Err(err))),
             };
             // handle comments
-            lazy_static! {
-                static ref COMMENT: Regex = Regex::new("#.*$").unwrap();
-            }
-            let line = COMMENT.replace(&line, "").trim_end().to_owned();
+            let line = if settings.strip_comments {
+                COMMENT
+                    .replace(&line, "$1")
+                    .replace(r"\#", "#")
+                    .trim_end()
+                    .to_owned()
+            } else {
+                line
+            };
 
             // handle escaped newlines
             let mut line_pieces = vec![line];
@@ -455,7 +493,7 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
                 }
             }
 
-            if peeking {
+            if settings.peeking {
                 self.pending_line = Some((line_number, line_pieces));
             }
             return Some((line_number, Ok(line)));
@@ -467,11 +505,15 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
     /// Doesn't apply the escaped newline replacement unless the predicate passes.
     fn next_line_if(
         &mut self,
-        escaped_newline_replacement: &'static str,
+        settings: NextLineSettings,
         predicate: impl FnOnce(&(usize, Result<String>)) -> bool,
     ) -> Option<(usize, Result<String>)> {
-        if predicate(&self.next_line(escaped_newline_replacement, true)?) {
-            self.next_line(escaped_newline_replacement, false)
+        let peek_settings = NextLineSettings {
+            peeking: true,
+            ..settings
+        };
+        if predicate(&self.next_line(peek_settings)?) {
+            self.next_line(settings)
         } else {
             None
         }
@@ -554,7 +596,12 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
             .map(|x| x.into())
             .collect::<Vec<String>>();
 
-        while let Some((_, x)) = self.next_line_if("\\\n", |(_, x)| {
+        let settings = NextLineSettings {
+            escaped_newline_replacement: "\\\n",
+            strip_comments: false,
+            ..Default::default()
+        };
+        while let Some((_, x)) = self.next_line_if(settings, |(_, x)| {
             x.as_ref()
                 .ok()
                 .map_or(false, |line| line.starts_with('\t') || line.is_empty())
@@ -695,7 +742,7 @@ impl<'a, 'parent, R: BufRead> MakefileReader<'a, 'parent, R> {
             }
             let mut value = TokenString::empty();
             // TODO what should be done with escaped newlines
-            while let Some((_, line)) = self.next_line(" ", false) {
+            while let Some((_, line)) = self.next_line(Default::default()) {
                 let line = line?;
                 if line == "endef" {
                     break;
@@ -980,7 +1027,6 @@ example: test\\#post
 info:
 \thello # there
 ";
-        eprintln!("{}", file);
         let args = Args::empty();
         let makefile = MakefileReader::read(&args, MacroSet::new(), Cursor::new(file), "")?;
         let makefile = makefile.finish();
@@ -994,7 +1040,6 @@ info:
                 already_updated: Cell::new(false)
             }
         );
-        dbg!(&makefile.targets);
         assert_eq!(
             makefile.targets["example"],
             Target {
@@ -1005,6 +1050,16 @@ info:
                 already_updated: Cell::new(false)
             }
         );
+        assert_eq!(
+            makefile.targets["info"],
+            Target {
+                name: "info".to_owned(),
+                prerequisites: vec![],
+                commands: vec![CommandLine::from(TokenString::text("hello # there")),],
+                stem: None,
+                already_updated: Cell::new(false)
+            }
+        );
 
         Ok(())
     }
-- 
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