feat(tools/cheddar): allow disabling tagfilter extension

Makes it possible to do things like embedding YouTube videos in blog
posts rendered through Cheddar.

Change-Id: I6aed943c7bec0167b9f009d36dd067c52c6d3083
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9275
Tested-by: BuildkiteCI
Reviewed-by: Mark Shevchenko <markshevchenko@gmail.com>

tools/cheddar/src/bin/cheddar.rs

@@ -48,7 +48,7 @@ fn markdown_endpoint(request: &rouille::Request) -> rouille::Response {
 
     for text in texts.values_mut() {
         let mut buf: Vec<u8> = Vec::new();
-        format_markdown(&mut text.as_bytes(), &mut buf);
+        format_markdown(&mut text.as_bytes(), &mut buf, true);
         *text = String::from_utf8_lossy(&buf).to_string();
     }
 
@@ -89,6 +89,12 @@ fn main() {
                 .long("about-filter")
                 .takes_value(false),
         )
+        .arg(
+            Arg::with_name("no-tagfilter")
+                .help("Disable HTML tag filter")
+                .long("no-tagfilter")
+                .takes_value(false),
+        )
         .arg(
             Arg::with_name("sourcegraph-server")
                 .help("Run as a Sourcegraph compatible web-server")
@@ -122,7 +128,11 @@ fn main() {
     let mut out_handle = stdout.lock();
 
     if matches.is_present("about-filter") && filename.ends_with(".md") {
-        format_markdown(&mut in_handle, &mut out_handle);
+        format_markdown(
+            &mut in_handle,
+            &mut out_handle,
+            !matches.is_present("no-tagfilter"),
+        );
     } else {
         format_code(
             &THEMES.themes["InspiredGitHub"],

tools/cheddar/src/lib.rs

@@ -233,6 +233,7 @@ fn format_callout_paragraph(callout: Callout) -> NodeValue {
 pub fn format_markdown_with_shortlinks<R: BufRead, W: Write>(
     reader: &mut R,
     writer: &mut W,
+    tagfilter: bool,
     shortlinks: &[Shortlink],
 ) {
     let document = {
@@ -244,7 +245,13 @@ pub fn format_markdown_with_shortlinks<R: BufRead, W: Write>(
     };
 
     let arena = Arena::new();
-    let root = parse_document(&arena, &linkify_shortlinks(document, shortlinks), &MD_OPTS);
+
+    let mut opts = MD_OPTS.clone();
+    if !tagfilter {
+        opts.extension.tagfilter = false;
+    }
+
+    let root = parse_document(&arena, &linkify_shortlinks(document, shortlinks), &opts);
 
     // This node must exist with a lifetime greater than that of the parsed AST
     // in case that callouts are encountered (otherwise insertion into the tree
@@ -280,11 +287,11 @@ pub fn format_markdown_with_shortlinks<R: BufRead, W: Write>(
         }
     });
 
-    format_html(root, &MD_OPTS, writer).expect("Markdown rendering failed");
+    format_html(root, &opts, writer).expect("Markdown rendering failed");
 }
 
-pub fn format_markdown<R: BufRead, W: Write>(reader: &mut R, writer: &mut W) {
-    format_markdown_with_shortlinks(reader, writer, &TVL_LINKS)
+pub fn format_markdown<R: BufRead, W: Write>(reader: &mut R, writer: &mut W, tagfilter: bool) {
+    format_markdown_with_shortlinks(reader, writer, tagfilter, &TVL_LINKS)
 }
 
 fn find_syntax_for_file(filename: &str) -> &'static SyntaxReference {

tools/cheddar/src/tests.rs

@@ -6,7 +6,7 @@ use std::io::BufReader;
 fn expect_markdown(input: &str, expected: &str) {
     let mut input_buf = BufReader::new(input.trim().as_bytes());
     let mut out_buf: Vec<u8> = vec![];
-    format_markdown(&mut input_buf, &mut out_buf);
+    format_markdown(&mut input_buf, &mut out_buf, true);
 
     let out_string = String::from_utf8(out_buf).expect("output should be UTF8");
     assert_eq!(out_string.trim(), expected.trim());