perf: drop wasted requests and reuse markdown renderers

pr edit with reviewers and other fields reads the pull request once,
org delete counts only repositories, org view counts concurrently,
team list skips the repository count of all-repository teams,
pr diff --web builds the URL locally, pr list re-reads pull requests
concurrently for review fields, and glamour renderers are built once
per width and color.

Signed-off-by: bircni <bircni@icloud.com>

internal/terminal/markdown.go

@@ -6,6 +6,7 @@ package terminal
 import (
 	"regexp"
 	"strings"
+	"sync"
 
 	"charm.land/glamour/v2"
 	"charm.land/glamour/v2/styles"
@@ -19,6 +20,34 @@ func MarkdownEnabled(preference string, outTTY bool) bool {
 // glamourLinks matches the OSC 8 hyperlinks that glamour writes for markdown links.
 var glamourLinks = regexp.MustCompile("\x1b\\]8;[^\x07\x1b]*(?:\x07|\x1b\\\\)")
 
+// renderers caches a glamour renderer per width and color, as building one parses its style each
+// time; the lock also serializes rendering.
+var renderers = struct {
+	sync.Mutex
+	byKey map[[2]int]*glamour.TermRenderer
+}{byKey: map[[2]int]*glamour.TermRenderer{}}
+
+func markdownRenderer(width int, color bool) (*glamour.TermRenderer, error) {
+	key := [2]int{width, 0}
+	if color {
+		key[1] = 1
+	}
+	if renderer := renderers.byKey[key]; renderer != nil {
+		return renderer, nil
+	}
+	style := styles.NoTTYStyleConfig
+	if color {
+		style = styles.DarkStyleConfig
+		// The terminal's own text color keeps body text readable on light backgrounds too.
+		style.Document.Color = nil
+	}
+	renderer, err := glamour.NewTermRenderer(glamour.WithStyles(style), glamour.WithWordWrap(width), glamour.WithPreservedNewLines())
+	if err == nil {
+		renderers.byKey[key] = renderer
+	}
+	return renderer, err
+}
+
 // Markdown renders sanitized markdown for d: wrapped to its width (80 when unknown), colored or plain,
 // with links only when d allows them. It keeps line breaks like Gitea does, and returns the sanitized
 // text unrendered if rendering fails.
@@ -28,17 +57,14 @@ func Markdown(text string, d Display) string {
 	if width <= 0 {
 		width = 80
 	}
-	style := styles.NoTTYStyleConfig
-	if d.Color {
-		style = styles.DarkStyleConfig
-		// The terminal's own text color keeps body text readable on light backgrounds too.
-		style.Document.Color = nil
-	}
-	renderer, err := glamour.NewTermRenderer(glamour.WithStyles(style), glamour.WithWordWrap(width), glamour.WithPreservedNewLines())
+	renderers.Lock()
+	renderer, err := markdownRenderer(width, d.Color)
 	if err != nil {
+		renderers.Unlock()
 		return text
 	}
 	rendered, err := renderer.Render(text)
+	renderers.Unlock()
 	if err != nil {
 		return text
 	}