glob: add support for automatic path prefix

Support automatic path prefix with glob (`pathGlob` and `pathRegex`).
In this mode, pattern is prefixed with `File`-instance's path.

Standard java PatternMatch names `regex` and `glob` behaves
as they do in java world.

Default is `pathGlob`, that default behaviour is similar
with  Unix `ls` or with
[Python 3.5+ glob](https://docs.python.org/3/library/glob.html)

Please see pathikrit#114 for background information.

CHANGES.md

@@ -1,5 +1,6 @@
 ## v3.0.0
 
+* [PR #116](https://github.com/pathikrit/better-files/pull/116): Glob with automatic path
 * [Issue #107](https://github.com/pathikrit/better-files/issues/107): Handle Byte-order markers
 * [PR #113](https://github.com/pathikrit/better-files/pull/113): File anchor util
 * [Issue #105](https://github.com/pathikrit/better-files/issues/105): Remove dependency on scala.io

README.md

@@ -258,6 +258,10 @@ val matches: Iterator[File] = dir.glob("**/*.{java,scala}")
 // above code is equivalent to:
 dir.listRecursively.filter(f => f.extension == Some(".java") || f.extension == Some(".scala")) 
 ```
+List `*.txt` files:
+````scala
+    val txts = dir.glob("*.txt")
+````
 You can even use more advanced regex syntax instead of [glob syntax](http://docs.oracle.com/javase/tutorial/essential/io/fileOps.html#glob):
 ```scala
 val matches = dir.glob("^\\w*$")(syntax = File.PathMatcherSyntax.regex)

core/src/main/scala/better/files/File.scala

@@ -8,6 +8,7 @@ import java.nio.file._
 import java.nio.file.attribute._
 import java.security.{DigestInputStream, MessageDigest}
 import java.time.Instant
+import java.util.regex.Pattern
 import java.util.zip._
 import javax.xml.bind.DatatypeConverter
 
@@ -471,8 +472,41 @@ class File private(val path: Path) {
   def walk(maxDepth: Int = Int.MaxValue)(implicit visitOptions: File.VisitOptions = File.VisitOptions.default): Files =
     Files.walk(path, maxDepth, visitOptions: _*) //TODO: that ignores I/O errors?
 
-  def pathMatcher(syntax: File.PathMatcherSyntax)(pattern: String): PathMatcher =
-    fileSystem.getPathMatcher(s"${syntax.name}:$pattern")
+
+  /**
+   * Combine glob with path so that it will match relative path without leading glob-pattern.
+   */
+  protected def pathGlob(glob: String) = {
+    val escapedPath = (path.toString + fileSystem.getSeparator)
+      .replaceAllLiterally("""\\""", """\\\\""")
+      .replaceAllLiterally("*", "\\*")
+      .replaceAllLiterally("?", "\\?")
+      .replaceAllLiterally("{", "\\{")
+      .replaceAllLiterally("}", "\\}")
+      .replaceAllLiterally("[", "\\[")
+      .replaceAllLiterally("]", "\\]")
+
+    "glob:" + escapedPath + glob
+  }
+
+  /**
+   * Combine regex with path so that it will match relative path without leading regex-pattern.
+   */
+  protected def pathRegex(regex: String) = {
+    val pathWithSep = path.toString + fileSystem.getSeparator
+    "regex:" + Pattern.quote(pathWithSep) + regex
+  }
+
+  def pathMatcher(syntax: File.PathMatcherSyntax)(pattern: String): PathMatcher = {
+    if (syntax.name == "pathGlob") {
+      fileSystem.getPathMatcher(pathGlob(pattern))
+    } else if (syntax.name == "pathRegex") {
+      fileSystem.getPathMatcher(pathRegex(pattern))
+    } else {
+      fileSystem.getPathMatcher(s"${syntax.name}:$pattern")
+    }
+  }
+
 
   /**
     * Util to glob from this file's path
@@ -997,7 +1031,9 @@ object File {
   object PathMatcherSyntax {
     val glob = new PathMatcherSyntax("glob")
     val regex = new PathMatcherSyntax("regex")
-    val default = glob
+    val pathGlob = new PathMatcherSyntax("pathGlob")
+    val pathRegex = new PathMatcherSyntax("pathRegex")
+    val default = pathGlob
     def other(syntax: String) = new PathMatcherSyntax(syntax)
   }
 

core/src/test/scala/better/files/FileSpec.scala

@@ -169,7 +169,7 @@ class FileSpec extends FlatSpec with BeforeAndAfterEach with Matchers {
   }
 
   it should "glob" in {
-    a1.glob("**/*.txt").map(_.name).toSeq.sorted shouldEqual Seq("t1.txt", "t2.txt")
+    a1.glob("*.txt").map(_.name).toSeq.sorted shouldEqual Seq("t1.txt", "t2.txt")
     //a1.glob("*.txt").map(_.name).toSeq shouldEqual Seq("t1.txt", "t2.txt")
     testRoot.glob("**/*.txt").map(_.name).toSeq.sorted shouldEqual Seq("t1.txt", "t2.txt")
     val path = testRoot.path.toString.ensuring(testRoot.path.isAbsolute)
@@ -182,7 +182,7 @@ class FileSpec extends FlatSpec with BeforeAndAfterEach with Matchers {
     ("core"/"src"/"test").walk(maxDepth = 1) should have length 2
     ("core"/"src"/"test").walk(maxDepth = 0) should have length 1
     ("core"/"src"/"test").walk() should have length (("core"/"src"/"test").listRecursively.length + 1L)
-    ls_r("core"/"src"/"test") should have length 4
+    ls_r("core"/"src"/"test") should have length 5
   }
 
   it should "support names/extensions" in {