Use refactored Registers type

This is an unfortunately noisy change: we need to update virtually all
callsites that access the registers. For reads this means passing in the
Editor and for writes this means handling potential failure when we
can't write to a clipboard register.

7 files changed, 118 insertions, 206 deletions

diff --git a/helix-core/src/lib.rs b/helix-core/src/lib.rs
index e1b5a1a1..9a512eae 100644
--- a/helix-core/src/lib.rs
+++ b/helix-core/src/lib.rs
@@ -18,7 +18,6 @@ pub mod movement;
 pub mod object;
 pub mod path;
 mod position;
-pub mod register;
 pub mod search;
 pub mod selection;
 pub mod shellwords;
diff --git a/helix-core/src/register.rs b/helix-core/src/register.rs
deleted file mode 100644
index df68a759..00000000
--- a/helix-core/src/register.rs
+++ /dev/null
@@ -1,89 +0,0 @@
-use std::collections::HashMap;
-
-#[derive(Debug)]
-pub struct Register {
-    name: char,
-    values: Vec<String>,
-}
-
-impl Register {
-    pub const fn new(name: char) -> Self {
-        Self {
-            name,
-            values: Vec::new(),
-        }
-    }
-
-    pub fn new_with_values(name: char, values: Vec<String>) -> Self {
-        Self { name, values }
-    }
-
-    pub const fn name(&self) -> char {
-        self.name
-    }
-
-    pub fn read(&self) -> &[String] {
-        &self.values
-    }
-
-    pub fn write(&mut self, values: Vec<String>) {
-        self.values = values;
-    }
-
-    pub fn push(&mut self, value: String) {
-        self.values.push(value);
-    }
-}
-
-/// Currently just wraps a `HashMap` of `Register`s
-#[derive(Debug, Default)]
-pub struct Registers {
-    inner: HashMap<char, Register>,
-}
-
-impl Registers {
-    pub fn get(&self, name: char) -> Option<&Register> {
-        self.inner.get(&name)
-    }
-
-    pub fn read(&self, name: char) -> Option<&[String]> {
-        self.get(name).map(|reg| reg.read())
-    }
-
-    pub fn write(&mut self, name: char, values: Vec<String>) {
-        if name != '_' {
-            self.inner
-                .insert(name, Register::new_with_values(name, values));
-        }
-    }
-
-    pub fn push(&mut self, name: char, value: String) {
-        if name != '_' {
-            if let Some(r) = self.inner.get_mut(&name) {
-                r.push(value);
-            } else {
-                self.write(name, vec![value]);
-            }
-        }
-    }
-
-    pub fn first(&self, name: char) -> Option<&String> {
-        self.read(name).and_then(|entries| entries.first())
-    }
-
-    pub fn last(&self, name: char) -> Option<&String> {
-        self.read(name).and_then(|entries| entries.last())
-    }
-
-    pub fn inner(&self) -> &HashMap<char, Register> {
-        &self.inner
-    }
-
-    pub fn clear(&mut self) {
-        self.inner.clear();
-    }
-
-    pub fn remove(&mut self, name: char) -> Option<Register> {
-        self.inner.remove(&name)
-    }
-}
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 58c17296..d9ea580d 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -1847,11 +1847,11 @@ fn search_impl(
 
 fn search_completions(cx: &mut Context, reg: Option<char>) -> Vec<String> {
     let mut items = reg
-        .and_then(|reg| cx.editor.registers.get(reg))
-        .map_or(Vec::new(), |reg| reg.read().iter().take(200).collect());
+        .and_then(|reg| cx.editor.registers.read(reg, cx.editor))
+        .map_or(Vec::new(), |reg| reg.take(200).collect());
     items.sort_unstable();
     items.dedup();
-    items.into_iter().cloned().collect()
+    items.into_iter().map(|value| value.to_string()).collect()
 }
 
 fn search(cx: &mut Context) {
@@ -1910,9 +1910,8 @@ fn search_next_or_prev_impl(cx: &mut Context, movement: Movement, direction: Dir
     let count = cx.count();
     let config = cx.editor.config();
     let scrolloff = config.scrolloff;
-    let (_, doc) = current!(cx.editor);
-    let registers = &cx.editor.registers;
-    if let Some(query) = registers.read('/').and_then(|query| query.last()) {
+    if let Some(query) = cx.editor.registers.last('/', cx.editor) {
+        let doc = doc!(cx.editor);
         let contents = doc.text().slice(..).to_string();
         let search_config = &config.search;
         let case_insensitive = if search_config.smart_case {
@@ -1921,7 +1920,7 @@ fn search_next_or_prev_impl(cx: &mut Context, movement: Movement, direction: Dir
             false
         };
         let wrap_around = search_config.wrap_around;
-        if let Ok(regex) = RegexBuilder::new(query)
+        if let Ok(regex) = RegexBuilder::new(&query)
             .case_insensitive(case_insensitive)
             .multi_line(true)
             .build()
@@ -1974,12 +1973,14 @@ fn search_selection(cx: &mut Context) {
         .join("|");
 
     let msg = format!("register '{}' set to '{}'", '/', &regex);
-    cx.editor.registers.push('/', regex);
-    cx.editor.set_status(msg);
+    match cx.editor.registers.push('/', regex) {
+        Ok(_) => cx.editor.set_status(msg),
+        Err(err) => cx.editor.set_error(err.to_string()),
+    }
 }
 
 fn make_search_word_bounded(cx: &mut Context) {
-    let regex = match cx.editor.registers.last('/') {
+    let regex = match cx.editor.registers.last('/', cx.editor) {
         Some(regex) => regex,
         None => return,
     };
@@ -1997,14 +1998,16 @@ fn make_search_word_bounded(cx: &mut Context) {
     if !start_anchored {
         new_regex.push_str("\\b");
     }
-    new_regex.push_str(regex);
+    new_regex.push_str(&regex);
     if !end_anchored {
         new_regex.push_str("\\b");
     }
 
     let msg = format!("register '{}' set to '{}'", '/', &new_regex);
-    cx.editor.registers.push('/', new_regex);
-    cx.editor.set_status(msg);
+    match cx.editor.registers.push('/', new_regex) {
+        Ok(_) => cx.editor.set_status(msg),
+        Err(err) => cx.editor.set_error(err.to_string()),
+    }
 }
 
 fn global_search(cx: &mut Context) {
@@ -2367,7 +2370,10 @@ fn delete_selection_impl(cx: &mut Context, op: Operation) {
         let text = doc.text().slice(..);
         let values: Vec<String> = selection.fragments(text).map(Cow::into_owned).collect();
         let reg_name = cx.register.unwrap_or('"');
-        cx.editor.registers.write(reg_name, values);
+        if let Err(err) = cx.editor.registers.write(reg_name, values) {
+            cx.editor.set_error(err.to_string());
+            return;
+        }
     };
 
     // then delete
@@ -3758,18 +3764,16 @@ fn yank(cx: &mut Context) {
         .fragments(text)
         .map(Cow::into_owned)
         .collect();
+    let selections = values.len();
+    let register = cx.register.unwrap_or('"');
 
-    let msg = format!(
-        "yanked {} selection(s) to register {}",
-        values.len(),
-        cx.register.unwrap_or('"')
-    );
-
-    cx.editor
-        .registers
-        .write(cx.register.unwrap_or('"'), values);
+    match cx.editor.registers.write(register, values) {
+        Ok(_) => cx.editor.set_status(format!(
+            "yanked {selections} selection(s) to register {register}",
+        )),
+        Err(err) => cx.editor.set_error(err.to_string()),
+    }
 
-    cx.editor.set_status(msg);
     exit_select_mode(cx);
 }
 
@@ -3778,6 +3782,7 @@ fn yank_joined_impl(editor: &mut Editor, separator: &str, register: char) {
     let text = doc.text().slice(..);
 
     let selection = doc.selection(view.id);
+    let selections = selection.len();
     let joined = selection
         .fragments(text)
         .fold(String::new(), |mut acc, fragment| {
@@ -3788,14 +3793,12 @@ fn yank_joined_impl(editor: &mut Editor, separator: &str, register: char) {
             acc
         });
 
-    let msg = format!(
-        "joined and yanked {} selection(s) to register {}",
-        selection.len(),
-        register,
-    );
-
-    editor.registers.write(register, vec![joined]);
-    editor.set_status(msg);
+    match editor.registers.write(register, vec![joined]) {
+        Ok(_) => editor.set_status(format!(
+            "joined and yanked {selections} selection(s) to register {register}",
+        )),
+        Err(err) => editor.set_error(err.to_string()),
+    }
 }
 
 fn yank_joined(cx: &mut Context) {
@@ -4040,34 +4043,34 @@ fn paste_primary_clipboard_before(cx: &mut Context) {
 fn replace_with_yanked(cx: &mut Context) {
     let count = cx.count();
     let reg_name = cx.register.unwrap_or('"');
-    let (view, doc) = current!(cx.editor);
-    let registers = &mut cx.editor.registers;
-
-    if let Some(values) = registers.read(reg_name) {
-        if !values.is_empty() {
-            let repeat = std::iter::repeat(
-                values
-                    .last()
-                    .map(|value| Tendril::from(&value.repeat(count)))
-                    .unwrap(),
-            );
-            let mut values = values
-                .iter()
-                .map(|value| Tendril::from(&value.repeat(count)))
-                .chain(repeat);
-            let selection = doc.selection(view.id);
-            let transaction = Transaction::change_by_selection(doc.text(), selection, |range| {
-                if !range.is_empty() {
-                    (range.from(), range.to(), Some(values.next().unwrap()))
-                } else {
-                    (range.from(), range.to(), None)
-                }
-            });
 
-            doc.apply(&transaction, view.id);
-            exit_select_mode(cx);
+    let Some(values) = cx.editor.registers
+        .read(reg_name, cx.editor)
+        .filter(|values| values.len() > 0) else { return };
+    let values: Vec<_> = values.map(|value| value.to_string()).collect();
+
+    let (view, doc) = current!(cx.editor);
+    let repeat = std::iter::repeat(
+        values
+            .last()
+            .map(|value| Tendril::from(&value.repeat(count)))
+            .unwrap(),
+    );
+    let mut values = values
+        .iter()
+        .map(|value| Tendril::from(&value.repeat(count)))
+        .chain(repeat);
+    let selection = doc.selection(view.id);
+    let transaction = Transaction::change_by_selection(doc.text(), selection, |range| {
+        if !range.is_empty() {
+            (range.from(), range.to(), Some(values.next().unwrap()))
+        } else {
+            (range.from(), range.to(), None)
         }
-    }
+    });
+
+    doc.apply(&transaction, view.id);
+    exit_select_mode(cx);
 }
 
 fn replace_selections_with_clipboard_impl(
@@ -4109,12 +4112,12 @@ fn replace_selections_with_primary_clipboard(cx: &mut Context) {
 fn paste(cx: &mut Context, pos: Paste) {
     let count = cx.count();
     let reg_name = cx.register.unwrap_or('"');
-    let (view, doc) = current!(cx.editor);
-    let registers = &mut cx.editor.registers;
 
-    if let Some(values) = registers.read(reg_name) {
-        paste_impl(values, doc, view, pos, count, cx.editor.mode);
-    }
+    let Some(values) = cx.editor.registers.read(reg_name, cx.editor) else { return };
+    let values: Vec<_> = values.map(|value| value.to_string()).collect();
+
+    let (view, doc) = current!(cx.editor);
+    paste_impl(&values, doc, view, pos, count, cx.editor.mode);
 }
 
 fn paste_after(cx: &mut Context) {
@@ -5593,9 +5596,12 @@ fn record_macro(cx: &mut Context) {
                 }
             })
             .collect::<String>();
-        cx.editor.registers.write(reg, vec![s]);
-        cx.editor
-            .set_status(format!("Recorded to register [{}]", reg));
+        match cx.editor.registers.write(reg, vec![s]) {
+            Ok(_) => cx
+                .editor
+                .set_status(format!("Recorded to register [{}]", reg)),
+            Err(err) => cx.editor.set_error(err.to_string()),
+        }
     } else {
         let reg = cx.register.take().unwrap_or('@');
         cx.editor.macro_recording = Some((reg, Vec::new()));
@@ -5615,8 +5621,14 @@ fn replay_macro(cx: &mut Context) {
         return;
     }
 
-    let keys: Vec<KeyEvent> = if let Some([keys_str]) = cx.editor.registers.read(reg) {
-        match helix_view::input::parse_macro(keys_str) {
+    let keys: Vec<KeyEvent> = if let Some(keys) = cx
+        .editor
+        .registers
+        .read(reg, cx.editor)
+        .filter(|values| values.len() == 1)
+        .map(|mut values| values.next().unwrap())
+    {
+        match helix_view::input::parse_macro(&keys) {
             Ok(keys) => keys,
             Err(err) => {
                 cx.editor.set_error(format!("Invalid macro: {}", err));
diff --git a/helix-term/src/commands/typed.rs b/helix-term/src/commands/typed.rs
index 175f8bc6..28759b3f 100644
--- a/helix-term/src/commands/typed.rs
+++ b/helix-term/src/commands/typed.rs
@@ -2285,13 +2285,12 @@ fn clear_register(
         format!("Invalid register {}", args[0])
     );
     let register = args[0].chars().next().unwrap_or_default();
-    match cx.editor.registers.remove(register) {
-        Some(_) => cx
-            .editor
-            .set_status(format!("Register {} cleared", register)),
-        None => cx
-            .editor
-            .set_error(format!("Register {} not found", register)),
+    if cx.editor.registers.remove(register) {
+        cx.editor
+            .set_status(format!("Register {} cleared", register));
+    } else {
+        cx.editor
+            .set_error(format!("Register {} not found", register));
     }
     Ok(())
 }
diff --git a/helix-term/src/ui/prompt.rs b/helix-term/src/ui/prompt.rs
index 1352f493..8dc2906a 100644
--- a/helix-term/src/ui/prompt.rs
+++ b/helix-term/src/ui/prompt.rs
@@ -306,8 +306,8 @@ impl Prompt {
         direction: CompletionDirection,
     ) {
         (self.callback_fn)(cx, &self.line, PromptEvent::Abort);
-        let values = match cx.editor.registers.read(register) {
-            Some(values) if !values.is_empty() => values,
+        let mut values = match cx.editor.registers.read(register, cx.editor) {
+            Some(values) if values.len() > 0 => values,
             _ => return,
         };
 
@@ -315,13 +315,16 @@ impl Prompt {
 
         let index = match direction {
             CompletionDirection::Forward => self.history_pos.map_or(0, |i| i + 1),
-            CompletionDirection::Backward => {
-                self.history_pos.unwrap_or(values.len()).saturating_sub(1)
-            }
+            CompletionDirection::Backward => self
+                .history_pos
+                .unwrap_or_else(|| values.len())
+                .saturating_sub(1),
         }
         .min(end);
 
-        self.line = values[index].clone();
+        self.line = values.nth(index).unwrap().to_string();
+        // Appease the borrow checker.
+        drop(values);
 
         self.history_pos = Some(index);
 
@@ -470,7 +473,7 @@ impl Prompt {
             // Show the most recently entered value as a suggestion.
             if let Some(suggestion) = self
                 .history_register
-                .and_then(|reg| cx.editor.registers.last(reg))
+                .and_then(|reg| cx.editor.registers.last(reg, cx.editor))
             {
                 surface.set_string(line_area.x, line_area.y, suggestion, suggestion_color);
             }
@@ -567,25 +570,29 @@ impl Component for Prompt {
                 } else {
                     let last_item = self
                         .history_register
-                        .and_then(|reg| cx.editor.registers.last(reg).cloned())
-                        .map(|entry| entry.into())
-                        .unwrap_or_else(|| Cow::from(""));
+                        .and_then(|reg| cx.editor.registers.last(reg, cx.editor))
+                        .map(|entry| entry.to_string())
+                        .unwrap_or_else(|| String::from(""));
 
                     // handle executing with last command in history if nothing entered
-                    let input: Cow<str> = if self.line.is_empty() {
-                        last_item
+                    let input = if self.line.is_empty() {
+                        &last_item
                     } else {
                         if last_item != self.line {
                             // store in history
                             if let Some(register) = self.history_register {
-                                cx.editor.registers.push(register, self.line.clone());
+                                if let Err(err) =
+                                    cx.editor.registers.push(register, self.line.clone())
+                                {
+                                    cx.editor.set_error(err.to_string());
+                                }
                             };
                         }
 
-                        self.line.as_str().into()
+                        &self.line
                     };
 
-                    (self.callback_fn)(cx, &input, PromptEvent::Validate);
+                    (self.callback_fn)(cx, input, PromptEvent::Validate);
 
                     return close_fn;
                 }
@@ -617,25 +624,16 @@ impl Component for Prompt {
                 self.completion = cx
                     .editor
                     .registers
-                    .inner()
-                    .iter()
-                    .map(|(ch, reg)| {
-                        let content = reg
-                            .read()
-                            .get(0)
-                            .and_then(|s| s.lines().next().to_owned())
-                            .unwrap_or_default();
-                        (0.., format!("{} {}", ch, &content).into())
-                    })
+                    .iter_preview()
+                    .map(|(ch, preview)| (0.., format!("{} {}", ch, &preview).into()))
                     .collect();
                 self.next_char_handler = Some(Box::new(|prompt, c, context| {
                     prompt.insert_str(
-                        context
+                        &context
                             .editor
                             .registers
-                            .read(c)
-                            .and_then(|r| r.first())
-                            .map_or("", |r| r.as_str()),
+                            .first(c, context.editor)
+                            .unwrap_or_default(),
                         context.editor,
                     );
                 }));
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 20469ae9..1824ebf7 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -5,6 +5,7 @@ use crate::{
     graphics::{CursorKind, Rect},
     info::Info,
     input::KeyEvent,
+    register::Registers,
     theme::{self, Theme},
     tree::{self, Tree},
     view::ViewPosition,
@@ -40,7 +41,6 @@ use tokio::{
 use anyhow::{anyhow, bail, Error};
 
 pub use helix_core::diagnostic::Severity;
-pub use helix_core::register::Registers;
 use helix_core::{
     auto_pairs::AutoPairs,
     syntax::{self, AutoPairConfig, SoftWrap},
diff --git a/helix-view/src/info.rs b/helix-view/src/info.rs
index 1503e855..ca783fef 100644
--- a/helix-view/src/info.rs
+++ b/helix-view/src/info.rs
@@ -1,4 +1,5 @@
-use helix_core::{register::Registers, unicode::width::UnicodeWidthStr};
+use crate::register::Registers;
+use helix_core::unicode::width::UnicodeWidthStr;
 use std::fmt::Write;
 
 #[derive(Debug)]
@@ -56,16 +57,8 @@ impl Info {
 
     pub fn from_registers(registers: &Registers) -> Self {
         let body: Vec<_> = registers
-            .inner()
-            .iter()
-            .map(|(ch, reg)| {
-                let content = reg
-                    .read()
-                    .get(0)
-                    .and_then(|s| s.lines().next())
-                    .unwrap_or_default();
-                (ch.to_string(), content)
-            })
+            .iter_preview()
+            .map(|(ch, preview)| (ch.to_string(), preview))
             .collect();
 
         let mut infobox = Self::new("Registers", &body);