rustdoc: Improve comment stripping

There is less implicit removal of various comment styles, and it also removes
extraneous stars occasionally found in docblock comments. It turns out that the
bug for getops was just a differently formatted block.

Closes #9425
Closes #9417

Author: alexcrichton

src/libextra/getopts.rs

@@ -29,7 +29,7 @@
 //! that requires an input file to be specified, accepts an optional output
 //! file name following -o, and accepts both -h and --help as optional flags.
 //!
-//! ```
+//! ~~~{.rust}
 //! exter mod extra;
 //! use extra::getopts::*;
 //! use std::os;
@@ -75,7 +75,7 @@
 //!     };
 //!     do_work(input, output);
 //! }
-//! ```
+//! ~~~
 
 use std::cmp::Eq;
 use std::result::{Err, Ok};

src/libsyntax/parse/comments.rs

@@ -59,11 +59,19 @@ pub fn strip_doc_comment_decoration(comment: &str) -> ~str {
     fn vertical_trim(lines: ~[~str]) -> ~[~str] {
         let mut i = 0u;
         let mut j = lines.len();
+        // first line of all-stars should be omitted
+        if lines.len() > 0 && lines[0].iter().all(|c| c == '*') {
+            i += 1;
+        }
         while i < j && lines[i].trim().is_empty() {
-            i += 1u;
+            i += 1;
+        }
+        // like the first, a last line of all stars should be omitted
+        if j > i && lines[j - 1].iter().skip(1).all(|c| c == '*') {
+            j -= 1;
         }
-        while j > i && lines[j - 1u].trim().is_empty() {
-            j -= 1u;
+        while j > i && lines[j - 1].trim().is_empty() {
+            j -= 1;
         }
         return lines.slice(i, j).to_owned();
     }
@@ -106,8 +114,12 @@ pub fn strip_doc_comment_decoration(comment: &str) -> ~str {
         }
     }
 
-    if comment.starts_with("//") {
-        return comment.slice(3u, comment.len()).to_owned();
+    // one-line comments lose their prefix
+    static ONLINERS: &'static [&'static str] = &["///!", "///", "//!", "//"];
+    for prefix in ONLINERS.iter() {
+        if comment.starts_with(*prefix) {
+            return comment.slice_from(prefix.len()).to_owned();
+        }
     }
 
     if comment.starts_with("/*") {
@@ -384,29 +396,42 @@ mod test {
 
     #[test] fn test_block_doc_comment_1() {
         let comment = "/**\n * Test \n **  Test\n *   Test\n*/";
-        let correct_stripped = " Test \n*  Test\n   Test";
         let stripped = strip_doc_comment_decoration(comment);
-        assert_eq!(stripped.slice(0, stripped.len()), correct_stripped);
+        assert_eq!(stripped, ~" Test \n*  Test\n   Test");
     }
 
     #[test] fn test_block_doc_comment_2() {
         let comment = "/**\n * Test\n *  Test\n*/";
-        let correct_stripped = " Test\n  Test";
         let stripped = strip_doc_comment_decoration(comment);
-        assert_eq!(stripped.slice(0, stripped.len()), correct_stripped);
+        assert_eq!(stripped, ~" Test\n  Test");
     }
 
     #[test] fn test_block_doc_comment_3() {
         let comment = "/**\n let a: *int;\n *a = 5;\n*/";
-        let correct_stripped = " let a: *int;\n *a = 5;";
         let stripped = strip_doc_comment_decoration(comment);
-        assert_eq!(stripped.slice(0, stripped.len()), correct_stripped);
+        assert_eq!(stripped, ~" let a: *int;\n *a = 5;");
     }
 
-    #[test] fn test_line_doc_comment() {
-        let comment = "/// Test";
-        let correct_stripped = " Test";
+    #[test] fn test_block_doc_comment_4() {
+        let comment = "/*******************\n test\n *********************/";
         let stripped = strip_doc_comment_decoration(comment);
-        assert_eq!(stripped.slice(0, stripped.len()), correct_stripped);
+        assert_eq!(stripped, ~" test");
+    }
+
+    #[test] fn test_line_doc_comment() {
+        let stripped = strip_doc_comment_decoration("/// test");
+        assert_eq!(stripped, ~" test");
+        let stripped = strip_doc_comment_decoration("///! test");
+        assert_eq!(stripped, ~" test");
+        let stripped = strip_doc_comment_decoration("// test");
+        assert_eq!(stripped, ~" test");
+        let stripped = strip_doc_comment_decoration("// test");
+        assert_eq!(stripped, ~" test");
+        let stripped = strip_doc_comment_decoration("///test");
+        assert_eq!(stripped, ~"test");
+        let stripped = strip_doc_comment_decoration("///!test");
+        assert_eq!(stripped, ~"test");
+        let stripped = strip_doc_comment_decoration("//test");
+        assert_eq!(stripped, ~"test");
     }
 }