add support for git bisect

pkg/commands/git_commands/bisect_info.go

@@ -0,0 +1,103 @@
+package git_commands
+
+import "github.com/sirupsen/logrus"
+
+// although the typical terms in a git bisect are 'bad' and 'good', they're more
+// generally known as 'new' and 'old'. Semi-recently git allowed the user to define
+// their own terms e.g. when you want to used 'fixed', 'unfixed' in the event
+// that you're looking for a commit that fixed a bug.
+
+// Git bisect only keeps track of a single 'bad' commit. Once you pick a commit
+// that's older than the current bad one, it forgets about the previous one. On
+// the other hand, it does keep track of all the good and skipped commits.
+
+type BisectInfo struct {
+	log *logrus.Entry
+
+	// tells us whether all our git bisect files are there meaning we're in bisect mode.
+	// Doesn't necessarily mean that we've actually picked a good/bad commit yet.
+	started bool
+
+	// this is the ref you started the commit from
+	start string // this will always be defined
+
+	// these will be defined if we've started
+	newTerm string // 'bad' by default
+	oldTerm string // 'good' by default
+
+	// map of commit sha's to their status
+	statusMap map[string]BisectStatus
+
+	// the sha of the commit that's under test
+	current string
+}
+
+type BisectStatus int
+
+const (
+	BisectStatusOld BisectStatus = iota
+	BisectStatusNew
+	BisectStatusSkipped
+)
+
+// null object pattern
+func NewNullBisectInfo() *BisectInfo {
+	return &BisectInfo{started: false}
+}
+
+func (self *BisectInfo) GetNewSha() string {
+	for sha, status := range self.statusMap {
+		if status == BisectStatusNew {
+			return sha
+		}
+	}
+
+	return ""
+}
+
+func (self *BisectInfo) GetCurrentSha() string {
+	return self.current
+}
+
+func (self *BisectInfo) StartSha() string {
+	return self.start
+}
+
+func (self *BisectInfo) Status(commitSha string) (BisectStatus, bool) {
+	status, ok := self.statusMap[commitSha]
+	return status, ok
+}
+
+func (self *BisectInfo) NewTerm() string {
+	return self.newTerm
+}
+
+func (self *BisectInfo) OldTerm() string {
+	return self.oldTerm
+}
+
+// this is for when we have called `git bisect start`. It does not
+// mean that we have actually started narrowing things down or selecting good/bad commits
+func (self *BisectInfo) Started() bool {
+	return self.started
+}
+
+// this is where we have both a good and bad revision and we're actually
+// starting to narrow things down
+func (self *BisectInfo) Bisecting() bool {
+	if !self.Started() {
+		return false
+	}
+
+	if self.GetNewSha() == "" {
+		return false
+	}
+
+	for _, status := range self.statusMap {
+		if status == BisectStatusOld {
+			return true
+		}
+	}
+
+	return false
+}