Major refactoring to lower memory consumption.

Package has been split into multiple structure loaded on demand: files, extra, depends.

They're saved and loaded completely separately.

debian/package_files.go

@@ -0,0 +1,78 @@
+package debian
+
+import (
+	"encoding/binary"
+	"github.com/smira/aptly/aptly"
+	"github.com/smira/aptly/utils"
+	"hash/fnv"
+	"os"
+	"path/filepath"
+	"sort"
+)
+
+// PackageFile is a single file entry in package
+type PackageFile struct {
+	// Filename is name of file for the package (without directory)
+	Filename string
+	// Hashes for the file
+	Checksums utils.ChecksumInfo
+	// Temporary field used while downloading, stored relative path on the mirror
+	downloadPath string
+}
+
+// Verify that package file is present and correct
+func (f *PackageFile) Verify(packagePool aptly.PackagePool) (bool, error) {
+	poolPath, err := packagePool.Path(f.Filename, f.Checksums.MD5)
+	if err != nil {
+		return false, err
+	}
+
+	st, err := os.Stat(poolPath)
+	if err != nil {
+		return false, nil
+	}
+
+	// verify size
+	// TODO: verify checksum if configured
+	return st.Size() == f.Checksums.Size, nil
+}
+
+// DownloadURL return relative URL to package download location
+func (f *PackageFile) DownloadURL() string {
+	return filepath.Join(f.downloadPath, f.Filename)
+}
+
+// PackageFiles is collection of package files
+type PackageFiles []PackageFile
+
+// Hash compute hash of all file items, sorting them first
+func (files PackageFiles) Hash() uint64 {
+	sort.Sort(files)
+
+	h := fnv.New64a()
+
+	for _, f := range files {
+		h.Write([]byte(f.Filename))
+		binary.Write(h, binary.BigEndian, f.Checksums.Size)
+		h.Write([]byte(f.Checksums.MD5))
+		h.Write([]byte(f.Checksums.SHA1))
+		h.Write([]byte(f.Checksums.SHA256))
+	}
+
+	return h.Sum64()
+}
+
+// Len returns number of files
+func (files PackageFiles) Len() int {
+	return len(files)
+}
+
+// Swap swaps elements
+func (files PackageFiles) Swap(i, j int) {
+	files[i], files[j] = files[j], files[i]
+}
+
+// Less compares by filename
+func (files PackageFiles) Less(i, j int) bool {
+	return files[i].Filename < files[j].Filename
+}