From 3afab84d697d82df1d4dfcc1948dd72dcdbe4c56 Mon Sep 17 00:00:00 2001
From: Nick Groenen <nick@groenen.me>
Date: Sun, 4 Aug 2024 23:58:15 +0200
Subject: [PATCH] Get frontmatter directly from pulldown-cmark

pulldown-cmark 0.10.0 introduced metadata blocks in
pulldown-cmark/pulldown-cmark#641. Using this we can drop the dependency
on matter and grab the frontmatter as we're consuming markdown events
from the note being parsed, instead of having to extract the frontmatter
separately.
---
 Cargo.lock | 17 -----------------
 Cargo.toml |  1 -
 src/lib.rs | 33 ++++++++++++++++++++++++++-------
 3 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a8db518..7416b7b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -331,12 +331,6 @@ version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
 
-[[package]]
-name = "lazy_static"
-version = "1.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
-
 [[package]]
 name = "libc"
 version = "0.2.155"
@@ -355,16 +349,6 @@ version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
 
-[[package]]
-name = "matter"
-version = "0.1.0-alpha4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc16e839c57e0ad77957c42d39baab3692a1c6fa47692066470cddc24a5b0cd0"
-dependencies = [
- "lazy_static",
- "regex",
-]
-
 [[package]]
 name = "memchr"
 version = "2.7.4"
@@ -379,7 +363,6 @@ dependencies = [
  "filetime",
  "gumdrop",
  "ignore",
- "matter",
  "pathdiff",
  "percent-encoding",
  "pretty_assertions",
diff --git a/Cargo.toml b/Cargo.toml
index 1109e75..1d23138 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,7 +28,6 @@ doc = false
 eyre = "0.6.12"
 gumdrop = "0.8.1"
 ignore = "0.4.22"
-matter = "0.1.0-alpha4"
 pathdiff = "0.2.1"
 percent-encoding = "2.3.1"
 pulldown-cmark = "0.11.0"
diff --git a/src/lib.rs b/src/lib.rs
index bab9cc2..3dfbdbf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -467,6 +467,7 @@ impl<'a> Exporter<'a> {
 
     #[allow(clippy::too_many_lines)]
     #[allow(clippy::panic_in_result_fn)]
+    #[allow(clippy::shadow_unrelated)]
     fn parse_obsidian_note<'b>(
         &self,
         path: &Path,
@@ -478,23 +479,40 @@ impl<'a> Exporter<'a> {
             });
         }
         let content = fs::read_to_string(path).context(ReadSnafu { path })?;
-        let (frontmatter, content) =
-            matter::matter(&content).unwrap_or((String::new(), content.clone()));
-        let frontmatter =
-            frontmatter_from_str(&frontmatter).context(FrontMatterDecodeSnafu { path })?;
+        let mut frontmatter = String::new();
 
         let parser_options = Options::ENABLE_TABLES
             | Options::ENABLE_FOOTNOTES
             | Options::ENABLE_STRIKETHROUGH
             | Options::ENABLE_TASKLISTS
-            | Options::ENABLE_MATH;
+            | Options::ENABLE_MATH
+            | Options::ENABLE_YAML_STYLE_METADATA_BLOCKS;
 
         let mut ref_parser = RefParser::new();
         let mut events = vec![];
         // Most of the time, a reference triggers 5 events: [ or ![, [, <text>, ], ]
         let mut buffer = Vec::with_capacity(5);
 
-        for event in Parser::new_ext(&content, parser_options) {
+        let mut parser = Parser::new_ext(&content, parser_options);
+        'outer: while let Some(event) = parser.next() {
+            // When encountering a metadata block (frontmatter), collect all events until getting
+            // to the end of the block, at which point the nested loop will break out to the outer
+            // loop again.
+            if matches!(event, Event::Start(Tag::MetadataBlock(_kind))) {
+                for event in parser.by_ref() {
+                    match event {
+                        Event::Text(cowstr) => frontmatter.push_str(&cowstr),
+                        Event::End(TagEnd::MetadataBlock(_kind)) => {
+                            continue 'outer;
+                        },
+                        _ => panic!(
+                            "Encountered an unexpected event while processing frontmatter in {}. Please report this as a bug with a copy of the note contents and this text: \n\nEvent: {:?}\n",
+                            path.display(),
+                            event
+                        ),
+                    }
+                }
+            }
             if ref_parser.state == RefParserState::Resetting {
                 events.append(&mut buffer);
                 buffer.clear();
@@ -583,8 +601,9 @@ impl<'a> Exporter<'a> {
         if !buffer.is_empty() {
             events.append(&mut buffer);
         }
+
         Ok((
-            frontmatter,
+            frontmatter_from_str(&frontmatter).context(FrontMatterDecodeSnafu { path })?,
             events.into_iter().map(event_to_owned).collect(),
         ))
     }