Keep file tree view icons consistent with icon theme (#33921)

Fix #33914

before:
![3000-gogitea-gitea-y4ulxr46c4k ws-us118 gitpod io_test_test
gitea_src_branch_main_
gitmodules](https://github.com/user-attachments/assets/ca50eeff-cc44-4041-b01f-c0c5bdd3b6aa)

after:
![3000-gogitea-gitea-y4ulxr46c4k ws-us118 gitpod io_test_test
gitea_src_branch_main_README
md](https://github.com/user-attachments/assets/3b87fdbd-81d0-4831-8a74-4dbfcd5b6d91)

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/fileicon/material.go

@@ -13,7 +13,6 @@ import (
 	"code.gitea.io/gitea/modules/json"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/options"
-	"code.gitea.io/gitea/modules/reqctx"
 	"code.gitea.io/gitea/modules/svg"
 )
 
@@ -62,13 +61,7 @@ func (m *MaterialIconProvider) loadData() {
 	log.Debug("Loaded material icon rules and SVG images")
 }
 
-func (m *MaterialIconProvider) renderFileIconSVG(ctx reqctx.RequestContext, name, svg, extraClass string) template.HTML {
-	data := ctx.GetData()
-	renderedSVGs, _ := data["_RenderedSVGs"].(map[string]bool)
-	if renderedSVGs == nil {
-		renderedSVGs = make(map[string]bool)
-		data["_RenderedSVGs"] = renderedSVGs
-	}
+func (m *MaterialIconProvider) renderFileIconSVG(p *RenderedIconPool, name, svg, extraClass string) template.HTML {
 	// This part is a bit hacky, but it works really well. It should be safe to do so because all SVG icons are generated by us.
 	// Will try to refactor this in the future.
 	if !strings.HasPrefix(svg, "<svg") {
@@ -76,16 +69,13 @@ func (m *MaterialIconProvider) renderFileIconSVG(ctx reqctx.RequestContext, name
 	}
 	svgID := "svg-mfi-" + name
 	svgCommonAttrs := `class="svg git-entry-icon ` + extraClass + `" width="16" height="16" aria-hidden="true"`
-	posOuterBefore := strings.IndexByte(svg, '>')
-	if renderedSVGs[svgID] && posOuterBefore != -1 {
-		return template.HTML(`<svg ` + svgCommonAttrs + `><use xlink:href="#` + svgID + `"></use></svg>`)
+	if p.IconSVGs[svgID] == "" {
+		p.IconSVGs[svgID] = template.HTML(`<svg id="` + svgID + `" ` + svgCommonAttrs + svg[4:])
 	}
-	svg = `<svg id="` + svgID + `" ` + svgCommonAttrs + svg[4:]
-	renderedSVGs[svgID] = true
-	return template.HTML(svg)
+	return template.HTML(`<svg ` + svgCommonAttrs + `><use xlink:href="#` + svgID + `"></use></svg>`)
 }
 
-func (m *MaterialIconProvider) FileIcon(ctx reqctx.RequestContext, entry *git.TreeEntry) template.HTML {
+func (m *MaterialIconProvider) FileIcon(p *RenderedIconPool, entry *git.TreeEntry) template.HTML {
 	if m.rules == nil {
 		return BasicThemeIcon(entry)
 	}
@@ -110,7 +100,7 @@ func (m *MaterialIconProvider) FileIcon(ctx reqctx.RequestContext, entry *git.Tr
 		case entry.IsSubModule():
 			extraClass = "octicon-file-submodule"
 		}
-		return m.renderFileIconSVG(ctx, name, iconSVG, extraClass)
+		return m.renderFileIconSVG(p, name, iconSVG, extraClass)
 	}
 	// TODO: use an interface or wrapper for git.Entry to make the code testable.
 	return BasicThemeIcon(entry)

modules/fileicon/render.go

@@ -0,0 +1,52 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package fileicon
+
+import (
+	"html/template"
+	"strings"
+
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+type RenderedIconPool struct {
+	IconSVGs map[string]template.HTML
+}
+
+func NewRenderedIconPool() *RenderedIconPool {
+	return &RenderedIconPool{
+		IconSVGs: make(map[string]template.HTML),
+	}
+}
+
+func (p *RenderedIconPool) RenderToHTML() template.HTML {
+	if len(p.IconSVGs) == 0 {
+		return ""
+	}
+	sb := &strings.Builder{}
+	sb.WriteString(`<div class=tw-hidden>`)
+	for _, icon := range p.IconSVGs {
+		sb.WriteString(string(icon))
+	}
+	sb.WriteString(`</div>`)
+	return template.HTML(sb.String())
+}
+
+// TODO: use an interface or struct to replace "*git.TreeEntry", to decouple the fileicon module from git module
+
+func RenderEntryIcon(renderedIconPool *RenderedIconPool, entry *git.TreeEntry) template.HTML {
+	if setting.UI.FileIconTheme == "material" {
+		return DefaultMaterialIconProvider().FileIcon(renderedIconPool, entry)
+	}
+	return BasicThemeIcon(entry)
+}
+
+func RenderEntryIconOpen(renderedIconPool *RenderedIconPool, entry *git.TreeEntry) template.HTML {
+	// TODO: add "open icon" support
+	if setting.UI.FileIconTheme == "material" {
+		return DefaultMaterialIconProvider().FileIcon(renderedIconPool, entry)
+	}
+	return BasicThemeIcon(entry)
+}