documents: format always reads apart; read cutoff back to 128 KiB

The format command never parses on the UI thread; refusals past the
size checks come by event. The document's at-once read returns to
128 KiB, so a visual opening between the cutoffs starts at the top.
Timing test takes web_time::Instant.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/documents/document/format/apply.rs

@@ -7,7 +7,7 @@ use gpui::{AppContext as _, Context};
 use super::{Change, FormatRefusal, InlineFormat, toggle};
 use crate::documents::{
     MarkdownMode,
-    document::{AT_ONCE, DocumentEvent, LARGEST_READ, MarkdownDocument},
+    document::{DocumentEvent, LARGEST_READ, MarkdownDocument},
     modes::joint,
 };
 
@@ -15,7 +15,7 @@ use crate::documents::{
 type Snapshot = (String, usize, Range<usize>);
 
 impl MarkdownDocument {
-    /// `format` at the selection; long texts refuse by event.
+    /// `format` at the selection, read apart; refusals by event.
     pub fn format(
         &mut self,
         format: InlineFormat,
@@ -36,12 +36,6 @@ impl MarkdownDocument {
             log::info!("markdown document: format {format:?} refused: one runs");
             return Err(FormatRefusal::Busy);
         }
-        if full.len() <= AT_ONCE {
-            let change = toggle(&full, selection, format).inspect_err(|why| {
-                log::info!("markdown document: format {format:?} refused: {why:?}");
-            })?;
-            return self.apply(format, change, &full, offset, cx);
-        }
         log::info!(
             "markdown document: format {format:?} reads {} bytes apart",
             full.len()

src/documents/document/mod.rs

@@ -41,7 +41,7 @@ use crate::{
 };
 
 /// Texts this long parse at once; longer ones elsewhere.
-const AT_ONCE: usize = 16 << 10;
+const AT_ONCE: usize = 128 << 10;
 
 /// Longer texts are never read: source alone.
 pub const LARGEST_READ: usize = 2 << 20;

src/documents/document/tests/format.rs

@@ -1,15 +1,15 @@
 //! Inline formats toggle as Typora's (R4.6).
 
-use std::{cell::RefCell, rc::Rc, time::Instant};
+use std::{cell::RefCell, rc::Rc};
 
 use gpui::{Entity, Modifiers, TestAppContext, VisualTestContext};
 use markdown::mdast::Node;
+use web_time::Instant;
 
 use super::{open, opened, press, text};
 use crate::documents::{
     DocumentEvent, FormatRefusal, InlineFormat, LARGEST_READ, MarkdownDocument, MarkdownMode,
     document::{
-        AT_ONCE,
         format::{toggle, toggle_tree},
         visual,
     },
@@ -145,6 +145,7 @@ fn an_open_block_stays_open_and_undoes_as_one_step(cx: &mut TestAppContext) {
             .format(InlineFormat::Strong, cx)
             .expect("formatted");
     });
+    cx.run_until_parked();
     assert_eq!(
         opened(&document, cx),
         "alpha **beta**",
@@ -172,6 +173,7 @@ fn the_source_takes_a_format_as_one_step(cx: &mut TestAppContext) {
             .update(cx, |editor, cx| editor.select(std::iter::once(2..2), cx));
         document.format(InlineFormat::Code, cx).expect("formatted");
     });
+    cx.run_until_parked();
     assert_eq!(text(&document, cx), "`alpha` beta\n");
     document.update(cx, |document, cx| {
         document.editor.update(cx, |editor, cx| editor.undo(cx));
@@ -221,8 +223,8 @@ fn underline_comes_off_past_other_tags() {
     assert_eq!(ok("<u>a <em>b‸c</em> d</u>", Underline), "a <em>b‸c</em> d");
 }
 
-/// A source document of one long word, caret at 1.
-fn long(cx: &mut TestAppContext, len: usize) -> (Entity<MarkdownDocument>, &mut VisualTestContext) {
+/// A source document of one word, caret at 1.
+fn word(cx: &mut TestAppContext, len: usize) -> (Entity<MarkdownDocument>, &mut VisualTestContext) {
     let (document, cx) = open(&"x".repeat(len), MarkdownMode::Source, cx);
     document.update(cx, |document, cx| {
         document
@@ -233,8 +235,8 @@ fn long(cx: &mut TestAppContext, len: usize) -> (Entity<MarkdownDocument>, &mut
 }
 
 #[gpui::test]
-fn a_long_text_formats_once_read_apart(cx: &mut TestAppContext) {
-    let (document, cx) = long(cx, AT_ONCE + 1);
+fn a_format_reads_apart(cx: &mut TestAppContext) {
+    let (document, cx) = word(cx, 64);
     document.update(cx, |document, cx| {
         document.format(InlineFormat::Strong, cx).expect("taken")
     });
@@ -248,7 +250,7 @@ fn a_long_text_formats_once_read_apart(cx: &mut TestAppContext) {
 
 #[gpui::test]
 fn many_short_paragraphs_format_apart(cx: &mut TestAppContext) {
-    let source = "a\n\n".repeat(AT_ONCE / 3 + 1);
+    let source = "a\n\n".repeat(100);
     let (document, cx) = open(&source, MarkdownMode::Source, cx);
     document.update(cx, |document, cx| {
         document
@@ -262,8 +264,8 @@ fn many_short_paragraphs_format_apart(cx: &mut TestAppContext) {
 }
 
 #[gpui::test]
-fn a_long_format_lapses_when_the_text_moves(cx: &mut TestAppContext) {
-    let (document, cx) = long(cx, AT_ONCE + 1);
+fn a_format_lapses_when_the_text_moves(cx: &mut TestAppContext) {
+    let (document, cx) = word(cx, 64);
     document.update(cx, |document, cx| {
         document.format(InlineFormat::Strong, cx).expect("taken");
         document
@@ -296,8 +298,8 @@ fn refusals(
 }
 
 #[gpui::test]
-fn a_long_lapse_comes_by_event(cx: &mut TestAppContext) {
-    let (document, cx) = long(cx, AT_ONCE + 1);
+fn a_lapse_comes_by_event(cx: &mut TestAppContext) {
+    let (document, cx) = word(cx, 64);
     let heard = refusals(&document, cx);
     document.update(cx, |document, cx| {
         document.format(InlineFormat::Strong, cx).expect("taken");
@@ -351,8 +353,8 @@ fn many_paragraphs_format_in_linear_time() {
 }
 
 #[gpui::test]
-fn a_second_long_format_refuses_while_one_runs(cx: &mut TestAppContext) {
-    let (document, cx) = long(cx, AT_ONCE + 1);
+fn a_second_format_refuses_while_one_runs(cx: &mut TestAppContext) {
+    let (document, cx) = word(cx, 64);
     let second = document.update(cx, |document, cx| {
         document.format(InlineFormat::Strong, cx).expect("taken");
         document.format(InlineFormat::Emphasis, cx)
@@ -372,8 +374,8 @@ fn a_second_long_format_refuses_while_one_runs(cx: &mut TestAppContext) {
 }
 
 #[gpui::test]
-fn a_long_refusal_comes_by_event(cx: &mut TestAppContext) {
-    let source = format!("`code` {}", "x".repeat(AT_ONCE));
+fn a_refusal_comes_by_event(cx: &mut TestAppContext) {
+    let source = format!("`code` {}", "x".repeat(64));
     let (document, cx) = open(&source, MarkdownMode::Source, cx);
     let heard = refusals(&document, cx);
     let taken = document.update(cx, |document, cx| {
@@ -389,8 +391,8 @@ fn a_long_refusal_comes_by_event(cx: &mut TestAppContext) {
 }
 
 #[gpui::test]
-fn a_long_format_drops_once_preview_shows(cx: &mut TestAppContext) {
-    let (document, cx) = long(cx, AT_ONCE + 1);
+fn a_format_drops_once_preview_shows(cx: &mut TestAppContext) {
+    let (document, cx) = word(cx, 64);
     let heard = refusals(&document, cx);
     document.update_in(cx, |document, window, cx| {
         document.format(InlineFormat::Strong, cx).expect("taken");
@@ -403,7 +405,25 @@ fn a_long_format_drops_once_preview_shows(cx: &mut TestAppContext) {
 
 #[gpui::test]
 fn a_text_past_the_largest_read_refuses(cx: &mut TestAppContext) {
-    let (document, cx) = long(cx, LARGEST_READ + 1);
+    let (document, cx) = word(cx, LARGEST_READ + 1);
     let refused = document.update(cx, |document, cx| document.format(InlineFormat::Strong, cx));
     assert_eq!(refused, Err(FormatRefusal::TooLong));
 }
+
+#[gpui::test]
+fn a_visual_format_reads_apart(cx: &mut TestAppContext) {
+    let (document, cx) = open("word\n\nmore\n", MarkdownMode::Visual, cx);
+    document.update(cx, |document, cx| {
+        document
+            .editor
+            .update(cx, |editor, cx| editor.select(std::iter::once(1..1), cx));
+        document.format(InlineFormat::Strong, cx).expect("taken");
+    });
+    assert_eq!(
+        text(&document, cx),
+        "word\n\nmore\n",
+        "not on the UI thread"
+    );
+    cx.run_until_parked();
+    assert_eq!(text(&document, cx), "**word**\n\nmore\n");
+}

src/documents/document/tests/place.rs

@@ -229,3 +229,11 @@ fn the_selection_reads_in_source_and_in_an_open_block(cx: &mut TestAppContext) {
         "words"
     );
 }
+
+#[gpui::test]
+fn a_visual_opening_starts_at_the_top(cx: &mut TestAppContext) {
+    let source = format!("alpha beta\n\n{}", "x".repeat(20000));
+    let (document, cx) = open(&source, MarkdownMode::Visual, cx);
+    cx.run_until_parked();
+    assert_eq!(landed(&document, cx), 0);
+}