Add UniqueSourceFileQueue

This is a queue of SourceFile objects, similar to UniqueStringQueue. It
is not used yet, only added.

Signed-off-by: Matthijs Kooijman <matthijs@stdin.nl>

Author: matthijskooijman

src/arduino.cc/builder/types/accessories.go

@@ -51,3 +51,26 @@ func (queue *UniqueStringQueue) Pop() interface{} {
 func (queue *UniqueStringQueue) Empty() bool {
 	return queue.Len() == 0
 }
+
+type UniqueSourceFileQueue []SourceFile
+
+func (queue UniqueSourceFileQueue) Len() int           { return len(queue) }
+func (queue UniqueSourceFileQueue) Less(i, j int) bool { return false }
+func (queue UniqueSourceFileQueue) Swap(i, j int)      { panic("Who called me?!?") }
+
+func (queue *UniqueSourceFileQueue) Push(value SourceFile) {
+	if !sliceContainsSourceFile(*queue, value) {
+		*queue = append(*queue, value)
+	}
+}
+
+func (queue *UniqueSourceFileQueue) Pop() SourceFile {
+	old := *queue
+	x := old[0]
+	*queue = old[1:]
+	return x
+}
+
+func (queue *UniqueSourceFileQueue) Empty() bool {
+	return queue.Len() == 0
+}

src/arduino.cc/builder/types/utils.go

@@ -38,3 +38,12 @@ func sliceContains(slice []string, target string) bool {
 	}
 	return false
 }
+
+func sliceContainsSourceFile(slice []SourceFile, target SourceFile) bool {
+	for _, elem := range slice {
+		if elem.Origin == target.Origin && elem.RelativePath == target.RelativePath {
+			return true
+		}
+	}
+	return false
+}