Refactor embedded assets and drop unnecessary dependencies (#34692)

Benefits:

1. smaller binary size (reduces more than 1MB)
2. better control of the assets details
3. fewer unmaintained dependencies
4. faster startup if the assets are not needed
5. won't hang up editors when open "bindata.go" by accident

modules/assetfs/embed_test.go

@@ -0,0 +1,98 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package assetfs
+
+import (
+	"bytes"
+	"io/fs"
+	"net/http"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEmbed(t *testing.T) {
+	tmpDir := t.TempDir()
+	tmpDataDir := tmpDir + "/data"
+	_ = os.MkdirAll(tmpDataDir+"/foo/bar", 0o755)
+	_ = os.WriteFile(tmpDataDir+"/a.txt", []byte("a"), 0o644)
+	_ = os.WriteFile(tmpDataDir+"/foo/bar/b.txt", bytes.Repeat([]byte("a"), 1000), 0o644)
+	_ = os.WriteFile(tmpDataDir+"/foo/c.txt", []byte("c"), 0o644)
+	require.NoError(t, GenerateEmbedBindata(tmpDataDir, tmpDir+"/out.dat"))
+
+	data, err := os.ReadFile(tmpDir + "/out.dat")
+	require.NoError(t, err)
+	efs := NewEmbeddedFS(data)
+
+	// test a non-existing file
+	_, err = fs.ReadFile(efs, "not exist")
+	assert.ErrorIs(t, err, fs.ErrNotExist)
+
+	// test a normal file (no compression)
+	content, err := fs.ReadFile(efs, "a.txt")
+	require.NoError(t, err)
+	assert.Equal(t, "a", string(content))
+	fi, err := fs.Stat(efs, "a.txt")
+	require.NoError(t, err)
+	_, ok := fi.(EmbeddedFileInfo).GetGzipContent()
+	assert.False(t, ok)
+
+	// test a compressed file
+	content, err = fs.ReadFile(efs, "foo/bar/b.txt")
+	require.NoError(t, err)
+	assert.Equal(t, bytes.Repeat([]byte("a"), 1000), content)
+	fi, err = fs.Stat(efs, "foo/bar/b.txt")
+	require.NoError(t, err)
+	assert.False(t, fi.Mode().IsDir())
+	assert.True(t, fi.Mode().IsRegular())
+	gzipContent, ok := fi.(EmbeddedFileInfo).GetGzipContent()
+	assert.True(t, ok)
+	assert.Greater(t, len(gzipContent), 1)
+	assert.Less(t, len(gzipContent), 1000)
+
+	// test list root directory
+	entries, err := fs.ReadDir(efs, ".")
+	require.NoError(t, err)
+	assert.Len(t, entries, 2)
+	assert.Equal(t, "a.txt", entries[0].Name())
+	assert.False(t, entries[0].IsDir())
+
+	// test list subdirectory
+	entries, err = fs.ReadDir(efs, "foo")
+	require.NoError(t, err)
+	require.Len(t, entries, 2)
+	assert.Equal(t, "bar", entries[0].Name())
+	assert.True(t, entries[0].IsDir())
+	assert.Equal(t, "c.txt", entries[1].Name())
+	assert.False(t, entries[1].IsDir())
+
+	// test directory mode
+	fi, err = fs.Stat(efs, "foo")
+	require.NoError(t, err)
+	assert.True(t, fi.IsDir())
+	assert.True(t, fi.Mode().IsDir())
+	assert.False(t, fi.Mode().IsRegular())
+
+	// test httpfs
+	hfs := http.FS(efs)
+	hf, err := hfs.Open("foo/bar/b.txt")
+	require.NoError(t, err)
+	hi, err := hf.Stat()
+	require.NoError(t, err)
+	fiEmbedded, ok := hi.(EmbeddedFileInfo)
+	require.True(t, ok)
+	gzipContent, ok = fiEmbedded.GetGzipContent()
+	assert.True(t, ok)
+	assert.Greater(t, len(gzipContent), 1)
+	assert.Less(t, len(gzipContent), 1000)
+
+	// test httpfs directory listing
+	hf, err = hfs.Open("foo")
+	require.NoError(t, err)
+	dirs, err := hf.Readdir(1)
+	require.NoError(t, err)
+	assert.Len(t, dirs, 1)
+}