From 469d748fd47d5c8d1faa5716b828e1c8be90d22e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Carlos=20Nieto?= <jose.carlos@menteslibres.net>
Date: Tue, 13 Dec 2016 04:25:07 +0000
Subject: [PATCH] Make db.And and db.Or immutable
---
db.go | 45 +++++++++++++++++++++++-----------
lib/sqlbuilder/builder_test.go | 2 +-
2 files changed, 32 insertions(+), 15 deletions(-)
diff --git a/db.go b/db.go
index bd665050..ed27d671 100644
--- a/db.go
+++ b/db.go
@@ -261,11 +261,16 @@ func (r rawValue) Empty() bool {
}
type compound struct {
- conds []Compound
+ prev *compound
+ fn func() []Compound
}
-func newCompound(c ...Compound) *compound {
- return &compound{c}
+func newCompound(conds ...Compound) *compound {
+ return &compound{
+ fn: func() []Compound {
+ return conds
+ },
+ }
}
func defaultJoin(in ...Compound) []Compound {
@@ -278,7 +283,7 @@ func defaultJoin(in ...Compound) []Compound {
}
func (c *compound) Sentences() []Compound {
- return c.conds
+ return compoundFastForward(c)
}
func (c *compound) Operator() CompoundOperator {
@@ -286,12 +291,26 @@ func (c *compound) Operator() CompoundOperator {
}
func (c *compound) Empty() bool {
- return len(c.conds) == 0
+ if c.fn == nil {
+ return false
+ }
+ return true
}
-func (c *compound) push(a ...Compound) *compound {
- c.conds = append(c.conds, a...)
- return c
+func (c *compound) frame(a []Compound) *compound {
+ if len(a) == 0 {
+ return c
+ }
+ nc := newCompound(a...)
+ nc.prev = c
+ return nc
+}
+
+func compoundFastForward(curr *compound) []Compound {
+ if curr == nil {
+ return []Compound{}
+ }
+ return append(compoundFastForward(curr.prev), curr.fn()...)
}
// Union represents a compound joined by OR.
@@ -301,8 +320,7 @@ type Union struct {
// Or adds more terms to the compound.
func (o *Union) Or(conds ...Compound) *Union {
- o.compound.push(defaultJoin(conds...)...)
- return o
+ return &Union{o.compound.frame(conds)}
}
// Operator returns the OR operator.
@@ -317,8 +335,7 @@ func (o *Union) Empty() bool {
// And adds more terms to the compound.
func (a *Intersection) And(conds ...Compound) *Intersection {
- a.compound.push(conds...)
- return a
+ return &Intersection{a.compound.frame(conds)}
}
// Empty returns false if this struct holds no conditions.
@@ -415,7 +432,7 @@ func (f *dbFunc) Name() string {
// db.Cond{"last_name": "Mouse"},
// )
func And(conds ...Compound) *Intersection {
- return &Intersection{compound: newCompound(conds...)}
+ return &Intersection{newCompound(conds...)}
}
// Or joins conditions under logical disjunction. Conditions can be represented
@@ -429,7 +446,7 @@ func And(conds ...Compound) *Intersection {
// db.Cond{"year": 1987},
// )
func Or(conds ...Compound) *Union {
- return &Union{compound: newCompound(defaultJoin(conds...)...)}
+ return &Union{newCompound(defaultJoin(conds...)...)}
}
// Raw marks chunks of data as protected, so they pass directly to the query
diff --git a/lib/sqlbuilder/builder_test.go b/lib/sqlbuilder/builder_test.go
index e4c72565..85ac2fd3 100644
--- a/lib/sqlbuilder/builder_test.go
+++ b/lib/sqlbuilder/builder_test.go
@@ -657,7 +657,7 @@ func TestSelect(t *testing.T) {
db.Raw("a.id IN ?", sq),
)
- cond.Or(db.Cond{"ml.mailing_list_id": []int{4, 5, 6}})
+ cond = cond.Or(db.Cond{"ml.mailing_list_id": []int{4, 5, 6}})
sel := b.
Select(db.Raw("DISTINCT ON(a.id) a.id"), db.Raw("COALESCE(NULLIF(ml.name,''), a.name) as name"), "a.email").
--
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