From c324e6f2122dcbc583a14231e2d61b739dea403a Mon Sep 17 00:00:00 2001
From: Mike Jensen <jent@threadly.org>
Date: Sun, 1 Dec 2024 21:45:12 -0700
Subject: [PATCH] Add `DeleteAll` function to clear the map

---
 ffmap/csv_map.go       |  8 ++++++++
 ffmap/csv_map_test.go  | 22 +++++++++++++++++++++-
 ffmap/file_map.go      |  7 +++++++
 ffmap/file_map_test.go | 16 ++++++++++++++++
 4 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/ffmap/csv_map.go b/ffmap/csv_map.go
index dd3e182..665306f 100644
--- a/ffmap/csv_map.go
+++ b/ffmap/csv_map.go
@@ -358,6 +358,14 @@ func (kv *KeyValueCSV) Delete(key string) {
 	delete(kv.data, key)
 }
 
+func (kv *KeyValueCSV) DeleteAll() {
+	kv.rwLock.Lock()
+	defer kv.rwLock.Unlock()
+
+	kv.modCount++
+	kv.data = make(map[string]dataItem)
+}
+
 // lockedRead will acquire a read lock before loading the value, use this function whenever you don't
 // already hold a lock.  Using this ensures that the read lock is promptly released.
 func (kv *KeyValueCSV) lockedRead(key string) (dataItem, bool) {
diff --git a/ffmap/csv_map_test.go b/ffmap/csv_map_test.go
index 8741737..84adcdb 100644
--- a/ffmap/csv_map_test.go
+++ b/ffmap/csv_map_test.go
@@ -1037,8 +1037,28 @@ func TestDelete(t *testing.T) {
 
 	m.Delete(key)
 
+	verifyEmpty(t, m, key)
+}
+
+func TestDeleteAll(t *testing.T) {
+	t.Parallel()
+	tmpFile, m := makeTestMap(t)
+	defer os.Remove(tmpFile)
+
+	key := "key"
+	require.NoError(t, m.Set(key, "value"))
+	require.NoError(t, m.Set("foo"+key, "value"))
+
+	m.DeleteAll()
+
+	verifyEmpty(t, m, key)
+}
+
+func verifyEmpty(t *testing.T, m *KeyValueCSV, oldKey string) {
+	t.Helper()
+
 	var result string
-	found, err := m.Get(key, &result)
+	found, err := m.Get(oldKey, &result)
 	require.NoError(t, err)
 	assert.False(t, found)
 	assert.Equal(t, 0, m.Size())
diff --git a/ffmap/file_map.go b/ffmap/file_map.go
index dbe0951..95d12be 100644
--- a/ffmap/file_map.go
+++ b/ffmap/file_map.go
@@ -37,6 +37,8 @@ type MutableFFMap interface {
 	Set(key string, value interface{}) error
 	// Delete will remove the key from the map (if present).
 	Delete(key string)
+	// DeleteAll will clear or delete all entries from the map.
+	DeleteAll()
 	// Commit will update the disk representation to match the in-memory state.  If this is not invoked the disk will
 	// never be updated.  This must not be called concurrently, and may be slow as the file format is optimized.
 	Commit() error
@@ -86,6 +88,11 @@ func (tfm *TypedFFMap[T]) Delete(key string) {
 	tfm.ffm.Delete(key)
 }
 
+// DeleteAll will clear or delete all entries from the map.
+func (tfm *TypedFFMap[T]) DeleteAll() {
+	tfm.ffm.DeleteAll()
+}
+
 // Commit will update the disk representation to match the in-memory state.  If this is not invoked the disk will
 // never be updated.  This must not be called concurrently, and may be slow as the file format is optimized.
 func (tfm *TypedFFMap[T]) Commit() error {
diff --git a/ffmap/file_map_test.go b/ffmap/file_map_test.go
index 74f03b8..f9ae123 100644
--- a/ffmap/file_map_test.go
+++ b/ffmap/file_map_test.go
@@ -60,6 +60,10 @@ func (m *memoryFFMap) Delete(key string) {
 	delete(m.data, key)
 }
 
+func (m *memoryFFMap) DeleteAll() {
+	m.data = make(map[string]interface{})
+}
+
 func (m *memoryFFMap) Commit() error {
 	return nil
 }
@@ -132,6 +136,18 @@ func TestTypedFFMap(t *testing.T) {
 		require.NoError(t, err)
 		tfm.Delete(key)
 
+		assert.False(t, tfm.ContainsKey(key))
+		assert.Equal(t, 0, tfm.Size())
+	})
+	t.Run("DeleteAll", func(t *testing.T) {
+		t.Parallel()
+		tfm := NewTypedFFMap[string](newMemoryFFMap())
+
+		key := "key"
+		require.NoError(t, tfm.Set(key, "value"))
+		require.NoError(t, tfm.Set("foo"+key, "value"))
+		tfm.DeleteAll()
+
 		assert.False(t, tfm.ContainsKey(key))
 		assert.Equal(t, 0, tfm.Size())
 	})