feat(blogo,plugins,foldingrenderer): foldingrenderer to have files render based on each other

blogo/plugin_foldingrenderer.go

@@ -0,0 +1,146 @@
+// Copyright 2025-present Gustavo "Guz" L. de Mello
+// Copyright 2025-present The Lored.dev Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package blogo
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"log/slog"
+)
+
+const foldingRendererPluginName = "blogo-foldingrenderer-renderer"
+
+type foldingRenderer struct {
+	plugins []RendererPlugin
+
+	panicOnInit bool
+
+	log *slog.Logger
+}
+
+type FoldingRendererOpts struct {
+	PanicOnInit bool
+
+	Logger *slog.Logger
+}
+
+type FoldingRenderer interface {
+	PluginWithPlugins
+	RendererPlugin
+}
+
+func NewFoldingRenderer(opts ...FoldingRendererOpts) FoldingRenderer {
+	opt := FoldingRendererOpts{}
+	if len(opts) > 0 {
+		opt = opts[0]
+	}
+
+	if opt.Logger == nil {
+		opt.Logger = slog.New(slog.NewTextHandler(io.Discard, &slog.HandlerOptions{}))
+	}
+	opt.Logger = opt.Logger.WithGroup(foldingRendererPluginName)
+
+	return &foldingRenderer{
+		plugins: []RendererPlugin{},
+
+		log: opt.Logger,
+	}
+}
+
+func (p *foldingRenderer) Name() string {
+	return foldingRendererPluginName
+}
+
+func (p *foldingRenderer) Use(plugin Plugin) {
+	log := p.log.With(slog.String("plugin", plugin.Name()))
+
+	if plg, ok := plugin.(RendererPlugin); ok {
+		p.plugins = append(p.plugins, plg)
+	} else {
+		m := fmt.Sprintf("failed to add plugin %q, since it doesn't implement RendererPlugin", plugin.Name())
+		log.Error(m)
+		if p.panicOnInit {
+			panic(fmt.Sprintf("%s: %s", multiRendererPluginName, m))
+		}
+	}
+}
+
+func (p *foldingRenderer) Render(src File, w io.Writer) error {
+	if len(p.plugins) == 0 {
+		_, err := io.Copy(w, src)
+		return err
+	}
+
+	f, err := newFoldignFile(src)
+	if err != nil {
+		return err
+	}
+
+	for _, r := range p.plugins {
+		err := r.Render(f, f)
+		if err != nil {
+			return err
+		}
+
+		if err := f.Fold(); err != nil {
+			return err
+		}
+	}
+
+	_, err = io.Copy(w, f)
+	return err
+}
+
+type foldingFile struct {
+	File
+	read   *bytes.Buffer
+	writer *bytes.Buffer
+}
+
+func newFoldignFile(f File) (*foldingFile, error) {
+	var r, w bytes.Buffer
+
+	if _, err := io.Copy(&r, f); err != nil {
+		return nil, err
+	}
+	if err := f.Close(); err != nil {
+		return nil, err
+	}
+
+	return &foldingFile{File: f, read: &r, writer: &w}, nil
+}
+
+func (f *foldingFile) Close() error {
+	return nil
+}
+
+func (f *foldingFile) Read(p []byte) (int, error) {
+	return f.read.Read(p)
+}
+
+func (f *foldingFile) Write(p []byte) (int, error) {
+	return f.writer.Write(p)
+}
+
+func (f *foldingFile) Fold() error {
+	f.read.Reset()
+	if _, err := io.Copy(f.writer, f.read); err != nil {
+		return err
+	}
+	f.writer.Reset()
+	return nil
+}