Support PostProcess for all file types

Not just HTML.

Fixes #10269

hugofs/hasbytes_fs.go

@@ -0,0 +1,90 @@
+// Copyright 2022 The Hugo Authors. All rights reserved.
+//
+// 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 hugofs
+
+import (
+	"os"
+
+	"github.com/gohugoio/hugo/common/hugio"
+	"github.com/spf13/afero"
+)
+
+var (
+	_ afero.Fs            = (*hasBytesFs)(nil)
+	_ FilesystemUnwrapper = (*hasBytesFs)(nil)
+)
+
+type hasBytesFs struct {
+	afero.Fs
+	hasBytesCallback func(name string, match bool)
+	pattern          []byte
+}
+
+func NewHasBytesReceiver(delegate afero.Fs, hasBytesCallback func(name string, match bool), pattern []byte) afero.Fs {
+	return &hasBytesFs{Fs: delegate, hasBytesCallback: hasBytesCallback, pattern: pattern}
+}
+
+func (fs *hasBytesFs) UnwrapFilesystem() afero.Fs {
+	return fs.Fs
+}
+
+func (fs *hasBytesFs) Create(name string) (afero.File, error) {
+	f, err := fs.Fs.Create(name)
+	if err == nil {
+		f = fs.wrapFile(f)
+	}
+	return f, err
+}
+
+func (fs *hasBytesFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
+	f, err := fs.Fs.OpenFile(name, flag, perm)
+	if err == nil && isWrite(flag) {
+		f = fs.wrapFile(f)
+	}
+	return f, err
+}
+
+func (fs *hasBytesFs) wrapFile(f afero.File) afero.File {
+	return &hasBytesFile{
+		File: f,
+		hbw: &hugio.HasBytesWriter{
+			Pattern: fs.pattern,
+		},
+		hasBytesCallback: fs.hasBytesCallback,
+	}
+
+}
+
+func (fs *hasBytesFs) Name() string {
+	return "hasBytesFs"
+}
+
+type hasBytesFile struct {
+	hasBytesCallback func(name string, match bool)
+	hbw              *hugio.HasBytesWriter
+	afero.File
+}
+
+func (h *hasBytesFile) Write(p []byte) (n int, err error) {
+	n, err = h.File.Write(p)
+	if err != nil {
+		return
+	}
+	return h.hbw.Write(p)
+}
+
+func (h *hasBytesFile) Close() error {
+	h.hasBytesCallback(h.Name(), h.hbw.Match)
+	return h.File.Close()
+}