View manpages in pager inside meli

Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>

meli/src/command.rs

@@ -143,6 +143,11 @@ impl TokenStream {
                             tokens.append(&mut m);
                         }
                     }
+                    AlternativeStrings(v) => {
+                        for t in v.iter() {
+                            sugg.insert(format!("{}{}", if s.is_empty() { " " } else { "" }, t));
+                        }
+                    }
                     Seq(_s) => {}
                     RestOfStringValue => {
                         sugg.insert(String::new());
@@ -196,6 +201,20 @@ impl TokenStream {
                         *s = "";
                     }
                 }
+                AlternativeStrings(v) => {
+                    for lit in v.iter() {
+                        if lit.starts_with(*s) && lit.len() != s.len() {
+                            sugg.insert(lit[s.len()..].to_string());
+                            tokens.push((s, *t.inner()));
+                            return tokens;
+                        } else if s.starts_with(lit) {
+                            tokens.push((&s[..lit.len()], *t.inner()));
+                            *s = &s[lit.len()..];
+                        } else {
+                            return vec![];
+                        }
+                    }
+                }
                 Seq(_s) => {
                     return vec![];
                 }
@@ -251,6 +270,7 @@ pub enum Token {
     Literal(&'static str),
     Filepath,
     Alternatives(&'static [TokenStream]),
+    AlternativeStrings(&'static [&'static str]),
     Seq(&'static [TokenAdicity]),
     AccountName,
     MailboxPath,
@@ -488,6 +508,18 @@ Alternatives(&[to_stream!(One(Literal("add-attachment")), One(Filepath)), to_str
                   tokens: &[One(Literal("manage-mailboxes"))],
                   parser: parser::manage_mailboxes
                 },
+                { tags: ["man"],
+                  desc: "read documentation",
+                  tokens: {
+                      #[cfg(feature = "cli-docs")]
+                      {
+                          &[One(Literal("man")), One(AlternativeStrings(crate::manpages::POSSIBLE_VALUES))]
+                      }
+                      #[cfg(not(feature = "cli-docs"))]
+                      { &[] }
+                  },
+                  parser: parser::view_manpage
+                },
                 { tags: ["manage-jobs"],
                   desc: "view and manage jobs",
                   tokens: &[One(Literal("manage-jobs"))],

meli/src/command/actions.rs

@@ -70,6 +70,8 @@ pub enum TabAction {
     New(Option<Box<dyn Component>>),
     ManageMailboxes,
     ManageJobs,
+    #[cfg(feature = "cli-docs")]
+    Man(crate::manpages::ManPages),
 }
 
 #[derive(Debug)]

meli/src/command/parser.rs

@@ -139,7 +139,7 @@ pub fn view(input: &[u8]) -> IResult<&[u8], Result<Action, CommandError>> {
 }
 
 pub fn new_tab(input: &[u8]) -> IResult<&[u8], Result<Action, CommandError>> {
-    alt((manage_mailboxes, manage_jobs, compose_action))(input)
+    alt((manage_mailboxes, manage_jobs, compose_action, view_manpage))(input)
 }
 
 pub fn parse_command(input: &[u8]) -> Result<Action, CommandError> {
@@ -999,6 +999,39 @@ pub fn manage_jobs(input: &[u8]) -> IResult<&[u8], Result<Action, CommandError>>
     let (input, _) = eof(input)?;
     Ok((input, Ok(Tab(ManageJobs))))
 }
+
+#[cfg(feature = "cli-docs")]
+pub fn view_manpage(input: &[u8]) -> IResult<&[u8], Result<Action, CommandError>> {
+    let mut check = arg_init! { min_arg:1, max_arg: 1, view_manpage };
+    let (input, _) = tag("man")(input.trim())?;
+    arg_chk!(start check, input);
+    let (input, _) = is_a(" ")(input)?;
+    arg_chk!(inc check, input);
+    let (input, manpage) = map_res(not_line_ending, std::str::from_utf8)(input.trim())?;
+    let (input, _) = eof(input)?;
+    arg_chk!(finish check, input);
+    match crate::manpages::parse_manpage(manpage) {
+        Ok(m) => Ok((input, Ok(Tab(Man(m))))),
+        Err(err) => Ok((
+            input,
+            Err(CommandError::BadValue {
+                inner: err.to_string().into(),
+                suggestions: Some(crate::manpages::POSSIBLE_VALUES),
+            }),
+        )),
+    }
+}
+
+#[cfg(not(feature = "cli-docs"))]
+pub fn view_manpage(input: &[u8]) -> IResult<&[u8], Result<Action, CommandError>> {
+    Ok((
+        input,
+        Err(CommandError::Other {
+            inner: "this meli binary has not been compiled with the cli-docs feature".into(),
+        }),
+    ))
+}
+
 pub fn quit(input: &[u8]) -> IResult<&[u8], Result<Action, CommandError>> {
     let mut check = arg_init! { min_arg:0, max_arg: 0, quit};
     let (input, _) = tag("quit")(input.trim())?;

meli/src/manpages.rs

@@ -172,4 +172,20 @@ impl ManPages {
 
         Ok(v)
     }
+
+    /// Helper function to remove backspace markup from mandoc output.
+    pub fn remove_markup(input: &str) -> Result<String> {
+        use std::{
+            io::Write,
+            process::{Command, Stdio},
+        };
+        let mut child = Command::new("col")
+            .arg("-b")
+            .arg("-x")
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .spawn()?;
+        child.stdin.as_mut().unwrap().write_all(input.as_bytes())?;
+        Ok(String::from_utf8_lossy(&child.wait_with_output()?.stdout).to_string())
+    }
 }

meli/src/state.rs

@@ -914,6 +914,27 @@ impl State {
                     )))
                     .unwrap();
             }
+            #[cfg(feature = "cli-docs")]
+            Tab(Man(manpage)) => match manpage
+                .read(false)
+                .map(|text| crate::manpages::ManPages::remove_markup(&text).unwrap_or(text))
+            {
+                Ok(m) => self.rcv_event(UIEvent::Action(Tab(New(Some(Box::new(
+                    Pager::from_string(
+                        m,
+                        Some(&self.context),
+                        None,
+                        None,
+                        crate::conf::value(&self.context, "theme_default"),
+                    ),
+                )))))),
+                Err(err) => self.context.replies.push_back(UIEvent::Notification {
+                    title: None,
+                    body: "Encountered an error while retrieving manual page.".into(),
+                    source: Some(err),
+                    kind: Some(NotificationType::Error(ErrorKind::Bug)),
+                }),
+            },
             v => {
                 self.rcv_event(UIEvent::Action(v));
             }

meli/src/utilities.rs

@@ -1386,7 +1386,7 @@ impl Component for Tabbed {
                 self.dirty = true;
                 return true;
             }
-            UIEvent::Action(Tab(New(ref mut e))) if e.is_some() => {
+            UIEvent::Action(Tab(New(ref mut e @ Some(_)))) => {
                 self.add_component(e.take().unwrap(), context);
                 self.children[self.cursor_pos]
                     .process_event(&mut UIEvent::VisibilityChange(false), context);

meli/src/utilities/pager.rs

@@ -877,4 +877,12 @@ impl Component for Pager {
     fn id(&self) -> ComponentId {
         self.id
     }
+
+    fn kill(&mut self, uuid: ComponentId, context: &mut Context) {
+        if self.id != uuid {
+            return;
+        }
+
+        context.replies.push_back(UIEvent::Action(Tab(Kill(uuid))));
+    }
 }