Implement zhash value

stdkiwi/store.go

@@ -113,6 +113,14 @@ func (s *Store) Zset(key string) *Zset {
 	}
 }
 
+// Zhash returns a "Zhash" with the key set as "key".
+func (s *Store) Zhash(key string) *Zhash {
+	return &Zhash{
+		store: s,
+		key:   key,
+	}
+}
+
 // Value can be used to access the methods for standard value types.
 type Value interface {
 	// Guard should panic if the key does not correspond to the correct type.

stdkiwi/zhash.go

@@ -0,0 +1,131 @@
+// Copyright (c) 2020 SDSLabs
+// Use of this source code is governed by an MIT license
+// details of which can be found in the LICENSE file.
+
+package stdkiwi
+
+import (
+	"github.com/sdslabs/kiwi/values/zhash"
+)
+
+// Zhash implements methods for zhash value type.
+type Zhash struct {
+	store *Store
+	key   string
+}
+
+// Guard guards the keys with values of str type.
+func (z *Zhash) Guard() {
+	if err := z.GuardE(); err != nil {
+		panic(err)
+	}
+}
+
+// GuardE is same as Guard but does not panic, instead returns the error.
+func (z *Zhash) GuardE() error { return z.store.guardValueE(zhash.Type, z.key) }
+
+// Insert inserts the elements to the zhash.
+func (z *Zhash) Insert(key, value string) error {
+	if _, err := z.store.Do(z.key, zhash.Insert, key, value); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Set sets the value of an pre-existing key of the zhash.
+func (z *Zhash) Set(key, value string) error {
+	if _, err := z.store.Do(z.key, zhash.Set, key, value); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Remove removes the elements from the zhash.
+func (z *Zhash) Remove(elements ...string) error {
+	if len(elements) == 0 {
+		return nil
+	}
+
+	ifaces := make([]interface{}, len(elements))
+	for i := range elements {
+		ifaces[i] = elements[i]
+	}
+
+	if _, err := z.store.Do(z.key, zhash.Remove, ifaces...); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Increment increment the score of element of the zhash.
+func (z *Zhash) Increment(element string, score int) error {
+	if _, err := z.store.Do(z.key, zhash.Increment, element, score); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Get gets the value and the score of element from the zhash.
+func (z *Zhash) Get(element string) (zhash.Item, error) {
+	v, err := z.store.Do(z.key, zhash.Get, element)
+	if err != nil {
+		return zhash.Item{}, err
+	}
+
+	val, ok := v.(zhash.Item)
+	if !ok {
+		return zhash.Item{}, newTypeErr(val, v)
+	}
+
+	return val, nil
+}
+
+// Len gets the length of the zhash.
+func (z *Zhash) Len() (int, error) {
+	v, err := z.store.Do(z.key, zhash.Len)
+	if err != nil {
+		return 0, err
+	}
+
+	length, ok := v.(int)
+	if !ok {
+		return 0, newTypeErr(length, v)
+	}
+
+	return length, nil
+}
+
+// PeekMax gets the element with highest score from the zhash.
+func (z *Zhash) PeekMax() (string, error) {
+	v, err := z.store.Do(z.key, zhash.PeekMax)
+	if err != nil {
+		return "", err
+	}
+
+	val, ok := v.(string)
+	if !ok {
+		return "", newTypeErr(val, v)
+	}
+
+	return val, nil
+}
+
+// PeekMin gets the element with minimum score from the zhash.
+func (z *Zhash) PeekMin() (string, error) {
+	v, err := z.store.Do(z.key, zhash.PeekMin)
+	if err != nil {
+		return "", err
+	}
+
+	val, ok := v.(string)
+	if !ok {
+		return "", newTypeErr(val, v)
+	}
+
+	return val, nil
+}
+
+// Interface guard.
+var _ Value = (*Set)(nil)

stdkiwi/zhash_test.go

@@ -0,0 +1,85 @@
+// Copyright (c) 2020 SDSLabs
+// Use of this source code is governed by an MIT license
+// details of which can be found in the LICENSE file.
+
+package stdkiwi
+
+import (
+	"testing"
+
+	"github.com/sdslabs/kiwi/values/zhash"
+)
+
+func TestZHash(t *testing.T) {
+	store := newTestStore(t, zhash.Type)
+	s := store.Zhash(testKey)
+
+	// check that it does not panic
+	s.Guard()
+
+	// and the same should work with GuardE as well
+	if err := s.GuardE(); err != nil {
+		t.Errorf("GuardE threw an error for default testKey: %v", err)
+	}
+
+	if err := s.Insert("a", "b"); err != nil {
+		t.Errorf("could not Insert: %v", err)
+	}
+	if err := s.Insert("c", "d"); err != nil {
+		t.Errorf("could not Insert: %v", err)
+	}
+
+	if err := s.Set("a", "e"); err != nil {
+		t.Errorf("could not Update: %v", err)
+	}
+
+	length, err := s.Len()
+	if err != nil {
+		t.Errorf("could not Len: %v", err)
+	}
+
+	if length != 2 {
+		t.Errorf("expected length of zset: %d; got %d", 2, length)
+	}
+
+	// updating score to some non zero values.
+
+	if err = s.Increment("a", 5); err != nil {
+		t.Errorf("could not increment: %v", err)
+	}
+
+	item, err := s.Get("c")
+	if err != nil {
+		t.Errorf("could not Get: %v", err)
+	}
+
+	if item.Score != 0 {
+		t.Errorf("expected score: %d; got: %d", 0, item.Score)
+	}
+
+	if item.Value != "d" {
+		t.Errorf("expected value: d; got %v", item.Value)
+	}
+
+	maxstr, err := s.PeekMax()
+	if err != nil {
+		t.Errorf("could not PeekMax: %v", err)
+	}
+
+	if maxstr != "a" {
+		t.Errorf("expected element: %q; got: %q", "a", maxstr)
+	}
+
+	minstr, err := s.PeekMin()
+	if err != nil {
+		t.Errorf("could not PeekMin: %v", err)
+	}
+
+	if minstr != "c" {
+		t.Errorf("expected element: %q; got: %q", "f", minstr)
+	}
+
+	if err := s.Remove("a", "c"); err != nil {
+		t.Errorf("Unexpected error when removing elements: %v", err)
+	}
+}

values/zhash/doc.go

@@ -0,0 +1,7 @@
+// Copyright (c) 2020 SDSLabs
+// Use of this source code is governed by an MIT license
+// details of which can be found in the LICENSE file.
+
+// Package zhash implements a kiwi.Value which can store a hash
+// with each element having a value and a score.
+package zhash