From 4fd7e1f821082607051ae5eb92c4d406ec7f0b7a Mon Sep 17 00:00:00 2001
From: Josh Baker <joshbaker77@gmail.com>
Date: Tue, 12 Jul 2016 12:48:40 -0600
Subject: [PATCH] support for parsing globs

---
 controller/glob/glob.go      | 91 ++++++++++++++++++++++++++++++++++++
 controller/glob/glob_test.go | 39 ++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 controller/glob/glob.go
 create mode 100644 controller/glob/glob_test.go

diff --git a/controller/glob/glob.go b/controller/glob/glob.go
new file mode 100644
index 00000000..b277b330
--- /dev/null
+++ b/controller/glob/glob.go
@@ -0,0 +1,91 @@
+package glob
+
+import "path"
+
+type Glob struct {
+	Pattern string
+	Desc    bool
+	Limits  []string
+	IsGlob  bool
+}
+
+func Match(pattern, name string) (matched bool, err error) {
+	return path.Match(pattern, name)
+}
+
+func IsGlob(pattern string) bool {
+	for i := 0; i < len(pattern); i++ {
+		switch pattern[i] {
+		case '[', '*', '?':
+			_, err := Match(pattern, "whatever")
+			return err == nil
+		}
+	}
+	return false
+}
+
+func Parse(pattern string, desc bool) *Glob {
+	g := &Glob{Pattern: pattern, Desc: desc, Limits: []string{"", ""}}
+	if pattern == "*" {
+		g.IsGlob = true
+		return g
+	}
+	if pattern == "" {
+		g.IsGlob = false
+		return g
+	}
+	n := 0
+	isGlob := false
+outer:
+	for i := 0; i < len(pattern); i++ {
+		switch pattern[i] {
+		case '[', '*', '?':
+			_, err := Match(pattern, "whatever")
+			if err == nil {
+				isGlob = true
+			}
+			break outer
+		}
+		n++
+	}
+	if n == 0 {
+		g.Limits = []string{pattern, pattern}
+		g.IsGlob = false
+		return g
+	}
+	var a, b string
+	if desc {
+		a = pattern[:n]
+		b = a
+		if b[n-1] == 0x00 {
+			for len(b) > 0 && b[len(b)-1] == 0x00 {
+				if len(b) > 1 {
+					if b[len(b)-2] == 0x00 {
+						b = b[:len(b)-1]
+					} else {
+						b = string(append([]byte(b[:len(b)-2]), b[len(b)-2]-1, 0xFF))
+					}
+				} else {
+					b = ""
+				}
+			}
+		} else {
+			b = string(append([]byte(b[:n-1]), b[n-1]-1))
+		}
+		if a[n-1] == 0xFF {
+			a = string(append([]byte(a), 0x00))
+		} else {
+			a = string(append([]byte(a[:n-1]), a[n-1]+1))
+		}
+	} else {
+		a = pattern[:n]
+		if a[n-1] == 0xFF {
+			b = string(append([]byte(a), 0x00))
+		} else {
+			b = string(append([]byte(a[:n-1]), a[n-1]+1))
+		}
+	}
+	g.Limits = []string{a, b}
+	g.IsGlob = isGlob
+	return g
+}
diff --git a/controller/glob/glob_test.go b/controller/glob/glob_test.go
new file mode 100644
index 00000000..39392e1d
--- /dev/null
+++ b/controller/glob/glob_test.go
@@ -0,0 +1,39 @@
+package glob
+
+import "testing"
+
+func TestGlob(t *testing.T) {
+	test := func(pattern string, desc bool, limitsExpect []string, isGlobExpect bool) {
+		g := Parse(pattern, desc)
+		if g.IsGlob != isGlobExpect {
+			t.Fatalf("pattern[%v] desc[%v] (isGlob=%v, expected=%v)", pattern, desc, g.IsGlob, isGlobExpect)
+		}
+		if g.Limits[0] != limitsExpect[0] || g.Limits[1] != limitsExpect[1] {
+			t.Fatalf("pattern[%v] desc[%v] (limits=%v, expected=%v)", pattern, desc, g.Limits, limitsExpect)
+		}
+		if g.Pattern != pattern {
+			t.Fatalf("pattern[%v] desc[%v] (pattern=%v, expected=%v)", pattern, desc, g.Pattern, pattern)
+		}
+		if g.Desc != desc {
+			t.Fatalf("pattern[%v] desc[%v] (desc=%v, expected=%v)", pattern, desc, g.Desc, desc)
+		}
+	}
+	test("*", false, []string{"", ""}, true)
+	test("", false, []string{"", ""}, false)
+	test("hello*", false, []string{"hello", "hellp"}, true)
+	test("hello", false, []string{"hello", "hellp"}, false)
+	test("\xff*", false, []string{"\xff", "\xff\x00"}, true)
+	test("\x00*", false, []string{"\x00", "\x01"}, true)
+	test("\xff", false, []string{"\xff", "\xff\x00"}, false)
+
+	test("*", true, []string{"", ""}, true)
+	test("", true, []string{"", ""}, false)
+	test("hello*", true, []string{"hellp", "helln"}, true)
+	test("hello", true, []string{"hellp", "helln"}, false)
+	test("a\xff*", true, []string{"a\xff\x00", "a\xfe"}, true)
+	test("\x00*", true, []string{"\x01", ""}, true)
+	test("\x01*", true, []string{"\x02", "\x00"}, true)
+	test("b\x00*", true, []string{"b\x01", "a\xff"}, true)
+	test("\x00\x00*", true, []string{"\x00\x01", ""}, true)
+	test("\x00\x01\x00*", true, []string{"\x00\x01\x01", "\x00\x00\xff"}, true)
+}