Add FormatThread function

FormatThread performs dfs on a thread tree. For every node in the tree,
a callback function is called with a thread and a format string for
that thread. The format string is to be used when displaying the full
thread tree.

Signed-off-by: Kevin Kuehler <keur@xcf.berkeley.edu>

1 files changed, 40 insertions, 0 deletions

diff --git a/worker/types/thread.go b/worker/types/thread.go
index 265438f..a51a5c4 100644
--- a/worker/types/thread.go
+++ b/worker/types/thread.go
@@ -4,3 +4,43 @@ type Thread struct {
 	Uid      uint32
 	Children []*Thread
 }
+
+func (t *Thread) FormatThread(cb func(*Thread, []rune) bool) {
+	cb(t, []rune{})
+	walkThreads(t.Children, []rune{}, cb)
+}
+
+func walkThreads(threads []*Thread, threadFmt []rune,
+	cb func(*Thread, []rune) bool) {
+	if threads == nil {
+		return
+	}
+
+	var (
+		indent          []rune = []rune{'\u0020', '\u0020'}
+		indentConnected []rune = []rune{'\u2502', '\u0020'}
+		arrow           []rune = []rune{'\u251c', '\u2500', '\u003e'}
+		arrowConnected  []rune = []rune{'\u2514', '\u2500', '\u003e'}
+
+		threadPrefix          []rune = append(threadFmt, arrow...)
+		threadPrefixConnected []rune = append(threadFmt, arrowConnected...)
+		nextThread            []rune = append(threadFmt, indent...)
+		nextThreadConnected   []rune = append(threadFmt, indentConnected...)
+	)
+
+	for i := len(threads) - 1; i >= 0; i-- {
+		t := threads[i]
+		if i > 0 && len(threads) > 1 {
+			if cb(t, threadPrefix) {
+				return
+			}
+			walkThreads(t.Children, nextThreadConnected, cb)
+		} else {
+			if cb(t, threadPrefixConnected) {
+				return
+			}
+			walkThreads(t.Children, nextThread, cb)
+		}
+	}
+
+}