From 55e5caed14454e1aabcdf5669680bc69bef4ab97 Mon Sep 17 00:00:00 2001
From: Harmen <harm@dds.nl>
Date: Sat, 20 Sep 2014 11:22:55 +0200
Subject: [PATCH] SREM

---
 README.md       |  1 +
 cmd_set.go      | 30 +++++++++++++++++++++++-
 cmd_set_test.go | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
 db.go           | 18 +++++++++++++++
 direct.go       | 18 +++++++++++++++
 5 files changed, 127 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 2af6abd8..7785d9ee 100644
--- a/README.md
+++ b/README.md
@@ -99,6 +99,7 @@ Implemented commands:
    - SCARD
    - SISMEMBER
    - SMEMBERS
+   - SREM
 
 
 Since this is intended to be used in unittests timeouts are not implemented.
diff --git a/cmd_set.go b/cmd_set.go
index 333519c9..599683a0 100644
--- a/cmd_set.go
+++ b/cmd_set.go
@@ -19,7 +19,7 @@ func commandsSet(m *Miniredis, srv *redeo.Server) {
 	// SMOVE source destination member
 	// SPOP key
 	// SRANDMEMBER key [count]
-	// SREM key member [member ...]
+	srv.HandleFunc("SREM", m.cmdSrem)
 	// SUNION key [key ...]
 	// SUNIONSTORE destination key [key ...]
 	// SSCAN key cursor [MATCH pattern] [COUNT count]
@@ -140,3 +140,31 @@ func (m *Miniredis) cmdSmembers(out *redeo.Responder, r *redeo.Request) error {
 		}
 	})
 }
+
+// SREM
+func (m *Miniredis) cmdSrem(out *redeo.Responder, r *redeo.Request) error {
+	if len(r.Args) < 2 {
+		setDirty(r.Client())
+		out.WriteErrorString("ERR wrong number of arguments for 'srem' command")
+		return nil
+	}
+
+	key := r.Args[0]
+	fields := r.Args[1:]
+
+	return withTx(m, out, r, func(out *redeo.Responder, ctx *connCtx) {
+		db := m.db(ctx.selectedDB)
+
+		if !db.exists(key) {
+			out.WriteInt(0)
+			return
+		}
+
+		if db.t(key) != "set" {
+			out.WriteErrorString(ErrWrongType.Error())
+			return
+		}
+
+		out.WriteInt(db.setrem(key, fields...))
+	})
+}
diff --git a/cmd_set_test.go b/cmd_set_test.go
index f3624246..94012c1a 100644
--- a/cmd_set_test.go
+++ b/cmd_set_test.go
@@ -133,3 +133,64 @@ func TestSismember(t *testing.T) {
 	}
 
 }
+
+// Test SREM
+func TestSrem(t *testing.T) {
+	s, err := Run()
+	ok(t, err)
+	defer s.Close()
+	c, err := redis.Dial("tcp", s.Addr())
+	ok(t, err)
+
+	s.SetAdd("s", "aap", "noot", "mies", "vuur")
+
+	{
+		b, err := redis.Int(c.Do("SREM", "s", "aap", "noot"))
+		ok(t, err)
+		equals(t, 2, b)
+
+		members, err := s.Members("s")
+		ok(t, err)
+		equals(t, []string{"mies", "vuur"}, members)
+	}
+
+	// a nonexisting field
+	{
+		b, err := redis.Int(c.Do("SREM", "s", "nosuch"))
+		ok(t, err)
+		equals(t, 0, b)
+	}
+
+	// a nonexisting key
+	{
+		b, err := redis.Int(c.Do("SREM", "nosuch", "nosuch"))
+		ok(t, err)
+		equals(t, 0, b)
+	}
+
+	// Direct usage
+	{
+		b, err := s.SRem("s", "mies")
+		ok(t, err)
+		equals(t, 1, b)
+
+		members, err := s.Members("s")
+		ok(t, err)
+		equals(t, []string{"vuur"}, members)
+	}
+
+	// Wrong type of key
+	{
+		_, err := redis.String(c.Do("SET", "str", "value"))
+		ok(t, err)
+		_, err = redis.Int(c.Do("SREM", "str", "value"))
+		assert(t, err != nil, "SREM error")
+		// Wrong argument counts
+		_, err = redis.String(c.Do("SREM"))
+		assert(t, err != nil, "SREM error")
+		_, err = redis.String(c.Do("SREM", "set"))
+		assert(t, err != nil, "SREM error")
+		_, err = redis.String(c.Do("SREM", "set", "spurious", "args"))
+		assert(t, err != nil, "SREM error")
+	}
+}
diff --git a/db.go b/db.go
index c7574539..44d077ad 100644
--- a/db.go
+++ b/db.go
@@ -200,6 +200,24 @@ func (db *RedisDB) setadd(k string, elems ...string) int {
 	return added
 }
 
+// setrem removes members from a set. Returns nr of deleted keys.
+func (db *RedisDB) setrem(k string, fields ...string) int {
+	s, ok := db.setKeys[k]
+	if !ok {
+		return 0
+	}
+	removed := 0
+	for _, f := range fields {
+		if _, ok := s[f]; ok {
+			removed++
+			delete(s, f)
+		}
+	}
+	db.setKeys[k] = s
+	db.keyVersion[k]++
+	return removed
+}
+
 // All members of a set.
 func (db *RedisDB) members(k string) []string {
 	set := db.setKeys[k]
diff --git a/direct.go b/direct.go
index 3d274710..d6a275b0 100644
--- a/direct.go
+++ b/direct.go
@@ -370,3 +370,21 @@ func (db *RedisDB) HIncrfloat(k, f string, delta float64) (float64, error) {
 	defer db.master.Unlock()
 	return db.hincrfloat(k, f, delta)
 }
+
+// SRem removes fields from a set. Returns number of deleted fields.
+func (m *Miniredis) SRem(k string, fields ...string) (int, error) {
+	return m.DB(m.selectedDB).SRem(k, fields...)
+}
+
+// SRem removes fields from a set. Returns number of deleted fields.
+func (db *RedisDB) SRem(k string, fields ...string) (int, error) {
+	db.master.Lock()
+	defer db.master.Unlock()
+	if !db.exists(k) {
+		return 0, ErrKeyNotFound
+	}
+	if db.t(k) != "set" {
+		return 0, ErrWrongType
+	}
+	return db.setrem(k, fields...), nil
+}