Moved archive package to public pkg/

pkg/archive/archive.go

@@ -0,0 +1,101 @@
+/*
+Copyright © 2025 Philipp Wolfer <phw@uploadedlobster.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+// Implements generic access to files inside an archive.
+//
+// An archive in this context can be any container that holds files.
+// In this implementation the archive can be a ZIP file or a directory.
+package archive
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+)
+
+// Generic interface to access files inside an archive.
+type ArchiveReader interface {
+	io.Closer
+
+	// Open the file inside the archive identified by the given path.
+	// The path is relative to the archive's root.
+	// The caller must call [fs.File.Close] when finished using the file.
+	Open(path string) (fs.File, error)
+
+	// List files inside the archive which satisfy the given glob pattern.
+	// This method only returns files, not directories.
+	Glob(pattern string) ([]FileInfo, error)
+}
+
+// Open an archive in path.
+// The archive can be a ZIP file or a directory. The implementation
+// will detect the type of archive and return the appropriate
+// implementation of the Archive interface.
+func OpenArchive(path string) (ArchiveReader, error) {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+	switch mode := fi.Mode(); {
+	case mode.IsRegular():
+		archive := &zipArchive{}
+		err := archive.OpenArchive(path)
+		if err != nil {
+			return nil, err
+		}
+		return archive, nil
+	case mode.IsDir():
+		archive := &dirArchive{}
+		err := archive.OpenArchive(path)
+		if err != nil {
+			return nil, err
+		}
+		return archive, nil
+	default:
+		return nil, fmt.Errorf("unsupported file mode: %s", mode)
+	}
+}
+
+// Interface for a file that can be opened when needed.
+type OpenableFile interface {
+	// Open the file for reading.
+	// The caller is responsible to call [io.ReadCloser.Close] when
+	// finished reading the file.
+	Open() (io.ReadCloser, error)
+}
+
+// Generic information about a file inside an archive.
+// This provides the filename and allows opening the file for reading.
+type FileInfo struct {
+	Name string
+	File OpenableFile
+}
+
+// A openable file in the filesystem.
+type filesystemFile struct {
+	path string
+}
+
+func (f *filesystemFile) Open() (io.ReadCloser, error) {
+	return os.Open(f.path)
+}