ini: add method to prune INI variables

Pruning the INI variables means removing the empty lines, the comments,
and merge section and subsection that have the same name into one
group.

3 files changed, 131 insertions, 0 deletions

diff --git a/lib/ini/ini.go b/lib/ini/ini.go
index 69fe21e1..01807d5b 100644
--- a/lib/ini/ini.go
+++ b/lib/ini/ini.go
@@ -242,6 +242,67 @@ func (in *Ini) Gets(section, subsection, key string) (out []string) {
 }
 
 //
+// Prune remove all empty lines, comments, and merge all section and
+// subsection with the same name into one group.
+//
+func (in *Ini) Prune() {
+	newSecs := make([]*Section, 0, len(in.secs))
+
+	for _, sec := range in.secs {
+		if sec.mode == varModeEmpty {
+			continue
+		}
+		newSec := &Section{
+			mode:      varModeSection,
+			Name:      sec.Name,
+			NameLower: sec.NameLower,
+		}
+		if len(sec.Sub) > 0 {
+			newSec.mode |= varModeSubsection
+			newSec.Sub = sec.Sub
+		}
+		for _, v := range sec.Vars {
+			if v.mode == varModeEmpty || v.mode == varModeComment {
+				continue
+			}
+
+			newValue := v.Value
+			if len(v.Value) == 0 {
+				newValue = "true"
+			}
+
+			newSec.AddUniqValue(v.Key, newValue)
+		}
+		newSecs = mergeSection(newSecs, newSec)
+	}
+
+	in.secs = newSecs
+}
+
+//
+// mergeSection merge a section (and subsection) into slice.
+//
+func mergeSection(secs []*Section, newSec *Section) []*Section {
+	for x := 0; x < len(secs); x++ {
+		if secs[x].NameLower != newSec.NameLower {
+			continue
+		}
+		if secs[x].Sub != newSec.Sub {
+			continue
+		}
+		for _, v := range newSec.Vars {
+			if v.mode == varModeEmpty || v.mode == varModeComment {
+				continue
+			}
+			secs[x].AddUniqValue(v.KeyLower, v.Value)
+		}
+		return secs
+	}
+	secs = append(secs, newSec)
+	return secs
+}
+
+//
 // Save the current parsed Ini into file `filename`. It will overwrite the
 // destination file if it's exist.
 //
diff --git a/lib/ini/ini_example_test.go b/lib/ini/ini_example_test.go
index 67c8966f..8ea5efbd 100644
--- a/lib/ini/ini_example_test.go
+++ b/lib/ini/ini_example_test.go
@@ -63,3 +63,46 @@ key=value3
 	// section::key2 = [true false]
 	// section:sub:key = [value1 value2 value3]
 }
+
+func ExampleIni_Prune() {
+	input := []byte(`
+[section]
+key=value1 # comment
+key2= ; another comment
+
+[section "sub"]
+key=value1
+
+; here is comment on section
+[section]
+key=value2
+key2=false
+
+[section "sub"]
+key=value2
+key=value1
+`)
+
+	in, err := Parse(input)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	in.Prune()
+
+	for _, sec := range in.secs {
+		fmt.Printf("%s", sec)
+		for _, v := range sec.Vars {
+			fmt.Printf("%s", v)
+		}
+	}
+	// Output:
+	// [section]
+	// key = value1
+	// key2 = true
+	// key = value2
+	// key2 = false
+	// [section "sub"]
+	// key = value2
+	// key = value1
+}
diff --git a/lib/ini/section.go b/lib/ini/section.go
index bc09cc23..3ac2f542 100644
--- a/lib/ini/section.go
+++ b/lib/ini/section.go
@@ -173,6 +173,33 @@ func (sec *Section) AddComment(comment string) {
 }
 
 //
+// AddUniqValue add a new variable with uniq value to section.
+// If variable with the same key and value found, that variable will be moved
+// to end of list, to make the last declared variable still at the end of
+// list.
+//
+func (sec *Section) AddUniqValue(key, value string) {
+	keyLower := strings.ToLower(key)
+	for x := 0; x < len(sec.Vars); x++ {
+		if sec.Vars[x].KeyLower == keyLower {
+			if sec.Vars[x].Value == value {
+				tmp := sec.Vars[x]
+				sec.Vars = append(sec.Vars[:x], sec.Vars[x+1:]...)
+				sec.Vars = append(sec.Vars, tmp)
+				return
+			}
+		}
+	}
+	v := &Variable{
+		mode:     varModeValue,
+		Key:      key,
+		KeyLower: keyLower,
+		Value:    value,
+	}
+	sec.Vars = append(sec.Vars, v)
+}
+
+//
 // Unset remove the variable with name `key` on current section.
 //
 // If key is empty, no variable will be removed, and it will return true.