2 files changed, 93 insertions, 0 deletions
diff --git a/pkg/storage/memstore/memstore.go b/pkg/storage/memstore/memstore.go
new file mode 100644
index 0000000..f0c60f5
--- /dev/null
+++ b/pkg/storage/memstore/memstore.go
@@ -0,0 +1,77 @@
+// Package memstore implements in-memory storage for atlas.
+package memstore
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/sha256"
+	"io"
+	"sync"
+)
+
+// PdataStore stores pdata in-memory, with optional compression.
+type PdataStore struct {
+	gzip  bool
+	pdata sync.Map
+}
+
+type pdataStoreEntry struct {
+	Hash [sha256.Size]byte
+	Data []byte
+}
+
+// NewPdataStore creates a new MemoryPdataStore.
+func NewPdataStore(compress bool) *PdataStore {
+	return &PdataStore{
+		gzip: compress,
+	}
+}
+
+func (m *PdataStore) GetPdataCached(uid uint64, sha [sha256.Size]byte) ([]byte, bool, error) {
+	v, ok := m.pdata.Load(uid)
+	if !ok {
+		return nil, ok, nil
+	}
+	e := v.(pdataStoreEntry)
+	if sha != [sha256.Size]byte{} && sha == e.Hash {
+		return nil, ok, nil
+	}
+	var b []byte
+	if m.gzip {
+		r, err := gzip.NewReader(bytes.NewReader(e.Data))
+		if err != nil {
+			return nil, ok, err
+		}
+		b, err = io.ReadAll(r)
+		if err != nil {
+			return nil, ok, err
+		}
+	} else {
+		b = make([]byte, len(e.Data))
+		copy(b, e.Data)
+	}
+	return b, ok, nil
+}
+
+func (m *PdataStore) SetPdata(uid uint64, buf []byte) error {
+	var b []byte
+	if m.gzip {
+		var f bytes.Buffer
+		w := gzip.NewWriter(&f)
+		if _, err := w.Write(buf); err != nil {
+			return err
+		}
+		if err := w.Close(); err != nil {
+			return err
+		}
+		b = f.Bytes()
+	} else {
+		b = make([]byte, len(buf))
+		copy(b, buf)
+	}
+	m.pdata.Store(uid, pdataStoreEntry{
+		Hash: sha256.Sum256(buf),
+		Data: b,
+	})
+	return nil
+}
diff --git a/pkg/storage/memstore/memstore_test.go b/pkg/storage/memstore/memstore_test.go
new file mode 100644
index 0000000..07a83e3
--- /dev/null
+++ b/pkg/storage/memstore/memstore_test.go
@@ -0,0 +1,16 @@
+package memstore
+
+import (
+	"testing"
+
+	"github.com/pg9182/atlas/pkg/api/api0/api0testutil"
+)
+
+func TestPdataStore(t *testing.T) {
+	t.Run("Default", func(t *testing.T) {
+		api0testutil.TestPdataStorage(t, NewPdataStore(false))
+	})
+	t.Run("Compressed", func(t *testing.T) {
+		api0testutil.TestPdataStorage(t, NewPdataStore(true))
+	})
+}