go-git-gitignore: copy matcher.go, pattern.go from go-git/plumbing/format/gitignore

Files copied from
https://github.com/go-git/go-git/tree/7bc22667c9e181cc1361eccec77f1a237abee860/plumbing/format/gitignore .

Importing all of go-git pulls in a metric ton of dependencies,
so I have decided to only copy the two files we need.

https://github.com/rfjakob/gocryptfs/issues/927

1 files changed, 30 insertions, 0 deletions

diff --git a/internal/go-git-gitignore/matcher.go b/internal/go-git-gitignore/matcher.go
new file mode 100644
index 0000000..bd1e9e2
--- /dev/null
+++ b/internal/go-git-gitignore/matcher.go
@@ -0,0 +1,30 @@
+package gitignore
+
+// Matcher defines a global multi-pattern matcher for gitignore patterns
+type Matcher interface {
+	// Match matches patterns in the order of priorities. As soon as an inclusion or
+	// exclusion is found, not further matching is performed.
+	Match(path []string, isDir bool) bool
+}
+
+// NewMatcher constructs a new global matcher. Patterns must be given in the order of
+// increasing priority. That is most generic settings files first, then the content of
+// the repo .gitignore, then content of .gitignore down the path or the repo and then
+// the content command line arguments.
+func NewMatcher(ps []Pattern) Matcher {
+	return &matcher{ps}
+}
+
+type matcher struct {
+	patterns []Pattern
+}
+
+func (m *matcher) Match(path []string, isDir bool) bool {
+	n := len(m.patterns)
+	for i := n - 1; i >= 0; i-- {
+		if match := m.patterns[i].Match(path, isDir); match > NoMatch {
+			return match == Exclude
+		}
+	}
+	return false
+}