Add preview support for help_tags (#630)

* Add preview for helptags

* Add clap#impl#on_move#async()

* Add fname and highlight the subject line

* Set the preview syntax to help

* Update CHANGELOG.md

* Fix clippy warnings

* .

CHANGELOG.md

@@ -10,6 +10,7 @@
 - Add `g:ClapProviderHistoryCustomFilter` for customizing the source of `history` provider. #615
 - Add a bonus for the match in the filename when the source item is a path, but you can only have this when you are using Python dynamic module or the Rust backend. #614.
 - Add a bonus for the files you opened since you enter vim. #622
+- Add async preview support for `help_tags` provider, the Rust binary is required. #630
 
 ### Fixed
 

autoload/clap/client.vim

@@ -31,6 +31,9 @@ function! clap#client#notify_on_init(method, ...) abort
         \   'provider_id': g:clap.provider.id,
         \   'source_fpath': expand('#'.g:clap.start.bufnr.':p'),
         \ }
+  if g:clap.provider.id ==# 'help_tags'
+    let params['runtimepath'] = &runtimepath
+  endif
   if a:0 > 0
     call extend(params, a:1)
   endif

autoload/clap/impl/on_move.vim

@@ -28,7 +28,9 @@ if clap#maple#is_available()
       catch
         return
       endtry
-      if has_key(a:result, 'fname')
+      if has_key(a:result, 'syntax')
+        call g:clap.preview.set_syntax(a:result.syntax)
+      elseif has_key(a:result, 'fname')
         call g:clap.preview.set_syntax(clap#ext#into_filetype(a:result.fname))
       endif
       call clap#preview#highlight_header()
@@ -45,10 +47,17 @@ if clap#maple#is_available()
     endif
     call s:sync_run_with_delay()
   endfunction
+
+  function! clap#impl#on_move#async() abort
+    return clap#client#call_on_move('on_move', function('s:handle_on_move_result'))
+  endfunction
 else
   function! s:dispatch_on_move_impl() abort
     call s:sync_run_with_delay()
   endfunction
+
+  function! clap#impl#on_move#async() abort
+  endfunction
 endif
 
 function! clap#impl#on_move#invoke() abort

autoload/clap/provider/help_tags.vim

@@ -4,6 +4,8 @@
 let s:save_cpo = &cpoptions
 set cpoptions&vim
 
+let s:help_tags = {}
+
 function! s:get_doc_tags() abort
   return ['/doc/tags'] + map(filter(split(&helplang, ','), 'v:val !=? "en"'), '"/doc/tags-".v:val')
 endfunction
@@ -27,6 +29,7 @@ if clap#maple#is_available() && clap#filter#sync#python#has_dynamic_module()
     endif
   endfunction
 
+  let s:help_tags.on_move_async = function('clap#impl#on_move#async')
 else
 
   let s:help_tags_memory_cache = []
@@ -78,7 +81,6 @@ else
   endfunction
 endif
 
-let s:help_tags = {}
 let s:help_tags.sink = function('s:help_tags_sink')
 let s:help_tags.source = function('s:help_tags_source')
 

build.rs

@@ -1,3 +1,4 @@
 fn main() {
-    built::write_built_file().expect("Failed to acquire build-time information");
+    built::write_built_file()
+        .unwrap_or_else(|e| panic!("Failed to acquire build-time information: {:?}", e));
 }

crates/maple_cli/src/cmd/cache.rs

@@ -53,7 +53,7 @@ impl Cache {
                             .file_name()
                             .and_then(std::ffi::OsStr::to_str)
                             .map(Into::into)
-                            .expect("Couldn't get file name")
+                            .unwrap_or_else(|| panic!("Couldn't get file name"))
                     })
                 })
                 .collect::<Result<Vec<String>, std::io::Error>>()?;
@@ -73,11 +73,11 @@ pub struct CacheEntry;
 impl CacheEntry {
     /// Construct the cache entry given command arguments and its working directory, the `total`
     /// info is cached in the file name.
-    pub fn new(cmd_args: &[&str], cmd_dir: Option<PathBuf>, total: usize) -> Result<PathBuf> {
+    pub fn try_new(cmd_args: &[&str], cmd_dir: Option<PathBuf>, total: usize) -> Result<PathBuf> {
         let mut dir = clap_cache_dir();
         dir.push(cmd_args.join("_"));
-        if let Some(mut cmd_dir) = cmd_dir {
-            dir.push(format!("{}", calculate_hash(&mut cmd_dir)));
+        if let Some(cmd_dir) = cmd_dir {
+            dir.push(format!("{}", calculate_hash(&cmd_dir)));
         } else {
             dir.push("no_cmd_dir");
         }
@@ -117,7 +117,7 @@ impl CacheEntry {
         total: usize,
         contents: T,
     ) -> Result<PathBuf> {
-        let entry = Self::new(cmd_args, cmd_dir, total)?;
+        let entry = Self::try_new(cmd_args, cmd_dir, total)?;
         Self::write(&entry, contents)?;
         Ok(entry)
     }

crates/maple_cli/src/light_command.rs

@@ -99,7 +99,7 @@ impl CommandEnv {
         if let Some(ref output) = self.output {
             Ok(output.into())
         } else {
-            CacheEntry::new(args, self.dir.clone(), self.total)
+            CacheEntry::try_new(args, self.dir.clone(), self.total)
         }
     }
 

crates/printer/src/lib.rs

@@ -65,7 +65,9 @@ pub fn truncate_long_matched_lines<T>(
             let line = item.display_text.unwrap_or(item.raw);
             lnum += 1;
             if !indices.is_empty() {
-                let last_idx = indices.last().expect("indices are non-empty; qed");
+                let last_idx = indices
+                    .last()
+                    .unwrap_or_else(|| panic!("indices are non-empty; qed"));
                 if *last_idx > winwidth {
                     let mut start = *last_idx - winwidth;
                     if start >= indices[0] || (indices.len() > 1 && *last_idx - start > winwidth) {
@@ -98,10 +100,10 @@ pub fn truncate_long_matched_lines<T>(
                     truncated_map.insert(lnum, line);
                     (truncated, score, truncated_indices)
                 } else {
-                    (line.into(), score, indices)
+                    (line, score, indices)
                 }
             } else {
-                (line.into(), score, indices)
+                (line, score, indices)
             }
         })
         .collect::<Vec<_>>();

crates/stdio_server/src/env.rs

@@ -34,7 +34,7 @@ pub fn initialize_global(msg: Message) {
     let preview_size = msg
         .params
         .get("clap_preview_size")
-        .expect("Missing clap_preview_size on initialize_global_env");
+        .unwrap_or_else(|| panic!("Missing clap_preview_size on initialize_global_env"));
 
     let global_env = GlobalEnv::new(is_nvim, enable_icon, preview_size.clone());
 

crates/stdio_server/src/lib.rs

@@ -77,6 +77,6 @@ where
         .spawn(move || {
             loop_read_rpc_message(reader, &tx);
         })
-        .expect("Failed to spawn rpc reader thread");
+        .unwrap_or_else(|_| panic!("Failed to spawn rpc reader thread"));
     loop_handle_rpc_message(&rx);
 }

crates/stdio_server/src/session/context.rs

@@ -9,6 +9,7 @@ pub struct SessionContext {
     pub source_cmd: Option<String>,
     pub winwidth: Option<u64>,
     pub provider_id: ProviderId,
+    pub runtimepath: Option<String>,
     pub start_buffer_path: String,
     pub is_running: Arc<Mutex<AtomicBool>>,
     pub source_list: Arc<Mutex<Option<Vec<String>>>>,
@@ -29,6 +30,11 @@ impl From<Message> for SessionContext {
 
         let cwd = msg.get_cwd();
 
+        let runtimepath = msg
+            .params
+            .get("runtimepath")
+            .and_then(|x| x.as_str().map(Into::into));
+
         let source_cmd = msg
             .params
             .get("source_cmd")
@@ -40,13 +46,14 @@ impl From<Message> for SessionContext {
             msg.params
                 .get("source_fpath")
                 .and_then(|x| x.as_str())
-                .expect("Missing source_fpath"),
+                .unwrap_or_else(|| panic!("Missing source_fpath")),
         );
 
         Self {
             provider_id,
             cwd,
             source_cmd,
+            runtimepath,
             winwidth,
             start_buffer_path,
             is_running: Arc::new(Mutex::new(true.into())),

crates/stdio_server/src/session/handler/mod.rs

@@ -24,8 +24,9 @@ impl HandleMessage for MessageHandler {
         match msg {
             RpcMessage::OnMove(msg) => {
                 let msg_id = msg.id;
-                if let Err(e) = on_move::OnMoveHandler::try_new(msg, context).map(|x| x.handle()) {
-                    write_response(json!({ "error": format!("{}",e), "id": msg_id }));
+                if let Err(e) = on_move::OnMoveHandler::try_new(&msg, context).map(|x| x.handle()) {
+                    log::debug!("Handle RpcMessage::OnMove {:?}, error: {:?}", msg, e);
+                    write_response(json!({"error": format!("{}",e), "id": msg_id }));
                 }
             }
             RpcMessage::OnTyped(msg) => on_typed::handle_on_typed(msg, context),

crates/stdio_server/src/session/handler/on_move.rs

@@ -19,6 +19,51 @@ pub fn as_absolute_path<P: AsRef<Path>>(path: P) -> Result<String> {
         .map_err(|e| anyhow!("{:?}, path:{}", e, path.as_ref().display()))
 }
 
+#[derive(Debug, Clone)]
+struct PreviewTag {
+    subject: String,
+    doc_filename: String,
+    runtimepath: String,
+}
+
+fn find_tag_line(p: &PathBuf, subject: &str) -> Option<usize> {
+    if let Ok(doc_lines) = utility::read_lines(p) {
+        for (idx, doc_line) in doc_lines.enumerate() {
+            if let Ok(d_line) = doc_line {
+                if d_line.trim().contains(&format!("*{}*", subject)) {
+                    return Some(idx);
+                }
+            }
+        }
+    }
+    None
+}
+
+impl PreviewTag {
+    pub fn new(subject: String, doc_filename: String, runtimepath: String) -> Self {
+        Self {
+            subject,
+            doc_filename,
+            runtimepath,
+        }
+    }
+
+    pub fn get_help_lines(&self, size: usize) -> Option<(String, Vec<String>)> {
+        for r in self.runtimepath.split(',') {
+            let p = Path::new(r).join("doc").join(&self.doc_filename);
+            if p.exists() {
+                if let Some(line_number) = find_tag_line(&p, &self.subject) {
+                    if let Ok(lines_iter) = utility::read_lines_from(&p, line_number, size) {
+                        return Some((format!("{}", p.display()), lines_iter.collect()));
+                    }
+                }
+            }
+        }
+
+        None
+    }
+}
+
 /// Preview environment on Vim CursorMoved event.
 #[derive(Debug, Clone)]
 #[allow(dead_code)]
@@ -27,10 +72,27 @@ pub enum OnMove {
     Files(PathBuf),
     Filer(PathBuf),
     History(PathBuf),
-    Grep { path: PathBuf, lnum: usize },
-    BLines { path: PathBuf, lnum: usize },
-    ProjTags { path: PathBuf, lnum: usize },
-    BufferTags { path: PathBuf, lnum: usize },
+    Grep {
+        path: PathBuf,
+        lnum: usize,
+    },
+    BLines {
+        path: PathBuf,
+        lnum: usize,
+    },
+    ProjTags {
+        path: PathBuf,
+        lnum: usize,
+    },
+    BufferTags {
+        path: PathBuf,
+        lnum: usize,
+    },
+    HelpTags {
+        subject: String,
+        doc_filename: String,
+        runtimepath: String,
+    },
 }
 
 /// Build the absolute path using cwd and relative path.
@@ -82,6 +144,23 @@ impl OnMove {
                 let path = context.start_buffer_path.clone().into();
                 Self::BufferTags { path, lnum }
             }
+            "help_tags" => {
+                let runtimepath = context
+                    .runtimepath
+                    .clone()
+                    .context("no runtimepath in the context")?;
+                let items = curline.split('\t').collect::<Vec<_>>();
+                if items.len() < 2 {
+                    return Err(anyhow!(
+                        "Can not extract subject and doc_filename from the line"
+                    ));
+                }
+                Self::HelpTags {
+                    subject: items[0].trim().to_string(),
+                    doc_filename: items[1].trim().to_string(),
+                    runtimepath,
+                }
+            }
             "commits" | "bcommits" => {
                 let rev = parse_rev(&curline).context("can not extract rev")?;
                 Self::Commit(rev.into())
@@ -107,7 +186,7 @@ pub struct OnMoveHandler<'a> {
 }
 
 impl<'a> OnMoveHandler<'a> {
-    pub fn try_new(msg: Message, context: &'a SessionContext) -> anyhow::Result<Self> {
+    pub fn try_new(msg: &Message, context: &'a SessionContext) -> anyhow::Result<Self> {
         let msg_id = msg.id;
         let provider_id = context.provider_id.clone();
         let curline = msg.get_curline(&provider_id)?;
@@ -140,6 +219,11 @@ impl<'a> OnMoveHandler<'a> {
                 debug!("path:{}, lnum:{}", path.display(), lnum);
                 self.preview_file_at(&path, *lnum);
             }
+            HelpTags {
+                subject,
+                doc_filename,
+                runtimepath,
+            } => self.preview_help_subject(subject, doc_filename, runtimepath),
             Filer(path) if path.is_dir() => {
                 self.preview_directory(&path)?;
             }
@@ -155,7 +239,7 @@ impl<'a> OnMoveHandler<'a> {
     }
 
     fn send_response(&self, result: serde_json::value::Value) {
-        let provider_id: crate::types::ProviderId = self.provider_id.clone().into();
+        let provider_id: crate::types::ProviderId = self.provider_id.clone();
         write_response(json!({
                 "id": self.msg_id,
                 "provider_id": provider_id,
@@ -177,6 +261,24 @@ impl<'a> OnMoveHandler<'a> {
         Ok(())
     }
 
+    fn preview_help_subject(&self, subject: &str, doc_filename: &str, runtimepath: &str) {
+        let preview_tag = PreviewTag::new(subject.into(), doc_filename.into(), runtimepath.into());
+        if let Some((fname, lines)) = preview_tag.get_help_lines(self.size * 2) {
+            let lines = std::iter::once(fname.clone())
+                .chain(lines.into_iter())
+                .collect::<Vec<_>>();
+            self.send_response(json!({
+              "event": "on_move",
+              "syntax": "help",
+              "lines": lines,
+              "hi_lnum": 1,
+              "fname": fname
+            }));
+        } else {
+            debug!("Can not find the preview help lines for {:?}", preview_tag);
+        }
+    }
+
     fn preview_file_at<P: AsRef<Path>>(&self, path: P, lnum: usize) {
         match utility::read_preview_lines(path.as_ref(), lnum, self.size) {
             Ok((lines_iter, hi_lnum)) => {

crates/stdio_server/src/types.rs

@@ -81,22 +81,22 @@ impl Message {
             .get(key)
             .and_then(|x| x.as_str())
             .map(Into::into)
-            .expect(&format!("Missing {} in msg.params", key))
+            .unwrap_or_else(|| panic!("Missing {} in msg.params", key))
     }
 
     fn _get_string(&self, key: &str) -> anyhow::Result<String> {
         self.params
             .get(key)
             .and_then(|x| x.as_str())
             .map(Into::into)
-            .ok_or(anyhow::anyhow!("Missing {} in msg.params", key))
+            .ok_or_else(|| anyhow::anyhow!("Missing {} in msg.params", key))
     }
 }
 
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct ProviderId(String);
 
-const NO_ICON_PROVIDERS: [&str; 3] = ["blines", "commits", "bcommits"];
+const NO_ICON_PROVIDERS: [&str; 4] = ["blines", "commits", "bcommits", "help_tags"];
 
 impl ProviderId {
     pub fn as_str(&self) -> &str {