Add JGitDatabase implementation of Database trait along with test-cases.

JGitDatabase implements all[T](fileType: FileType[T]): Iterator[File[T]] by
returning an iterator which encapsulates treeWalk to implement next method.

Signed-off-by: Grzegorz Kossakowski <grek@google.com>

3 files changed, 179 insertions, 0 deletions

diff --git a/src/main/scala/com/google/gimd/jgit/JGitDatabase.scala b/src/main/scala/com/google/gimd/jgit/JGitDatabase.scala
new file mode 100644
index 0000000..48f8009
--- /dev/null
+++ b/src/main/scala/com/google/gimd/jgit/JGitDatabase.scala
@@ -0,0 +1,69 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gimd.jgit
+
+import file.{FileType, File}
+import org.spearce.jgit.lib._
+import org.spearce.jgit.revwalk.{RevCommit, RevWalk}
+import org.spearce.jgit.treewalk.filter.{AndTreeFilter, PathFilter, PathSuffixFilter}
+import org.spearce.jgit.treewalk.filter.TreeFilter
+import org.spearce.jgit.treewalk.TreeWalk
+
+final class JGitDatabase(val jgitRepository: Repository) extends Database {
+
+  def all[T](fileType: FileType[T]): Iterator[File[T]] = {
+    val id = jgitRepository.resolve(Constants.HEAD)
+    val rw = new RevWalk(jgitRepository)
+    all(fileType, rw.parseCommit(id))
+  }
+
+  private def all[T](fileType: FileType[T], commit: RevCommit): Iterator[File[T]] = {
+    val treeWalk = new TreeWalk(jgitRepository)
+    treeWalk.reset(commit.getTree)
+    treeWalk.setRecursive(true)
+    treeWalk.setFilter(treeFilter(fileType))
+
+    val fileIterator = new Iterator[File[T]] {
+      private var doesHasNext = treeWalk.next
+      def hasNext = doesHasNext
+      def next = {
+        if (!hasNext)
+          throw new NoSuchElementException
+        val result =
+          new JGitFile(treeWalk.getPathString, treeWalk.getObjectId(0), fileType, jgitRepository)
+        doesHasNext = treeWalk.next
+        result
+      }
+    }
+    fileIterator
+  }
+
+  private def treeFilter[T](fileType: FileType[T]): TreeFilter =
+    AndTreeFilter.create(
+      Array(
+        RegularFileFilter,
+        fileType.pathPrefix.map(PathFilter.create(_)).getOrElse(TreeFilter.ALL),
+        fileType.pathSuffix.map(PathSuffixFilter.create(_)).getOrElse(TreeFilter.ALL)
+      )
+    )
+
+  private object RegularFileFilter extends TreeFilter {
+    def shouldBeRecursive = false
+    def include(treeWalk: TreeWalk) =
+      treeWalk.isSubtree || FileMode.REGULAR_FILE.equals(treeWalk.getFileMode(0))
+    override def clone = this
+  }
+
+}
diff --git a/src/test/scala/com/google/gimd/jgit/AbstractJGitTestCase.scala b/src/test/scala/com/google/gimd/jgit/AbstractJGitTestCase.scala
index e587f40..ab1562f 100644
--- a/src/test/scala/com/google/gimd/jgit/AbstractJGitTestCase.scala
+++ b/src/test/scala/com/google/gimd/jgit/AbstractJGitTestCase.scala
@@ -42,6 +42,9 @@ class AbstractJGitTestCase {
     ow.writeBlob(text.getBytes("UTF-8"))
   }
 
+  protected def writeMessage[U](userType: UserType[U], userObject: U): ObjectId =
+    writeTextContent(userType.toMessageBuffer(userObject).readOnly.toString)
+
   protected def addFiles(files: List[(String, ObjectId)]): ObjectId = {
     val dc = org.spearce.jgit.dircache.DirCache.newInCore
     val builder = dc.builder
diff --git a/src/test/scala/com/google/gimd/jgit/JGitDatabaseTestCase.scala b/src/test/scala/com/google/gimd/jgit/JGitDatabaseTestCase.scala
new file mode 100644
index 0000000..21a3cf2
--- /dev/null
+++ b/src/test/scala/com/google/gimd/jgit/JGitDatabaseTestCase.scala
@@ -0,0 +1,107 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gimd.jgit
+
+import file.{File, FileType}
+import org.junit.Test
+import org.junit.Assert._
+import org.spearce.jgit.lib.ObjectId
+
+final class JGitDatabaseTestCase extends AbstractJGitTestCase {
+
+  case class SimpleMessage(name: String, value: Int)
+
+  object SimpleMessageType extends UserType[SimpleMessage] {
+    def toMessageBuffer(sm: SimpleMessage) = (new MessageBuffer()) ++
+      List(Field("name", sm.name), Field("value", sm.value))
+    def toUserType(m: Message): SimpleMessage = {
+      val name = m.one("name").stringField.value
+      val value = m.one("value").intField.value
+      SimpleMessage(name, value)
+    }
+  }
+
+  object SimpleMessageFileType extends FileType[SimpleMessage] {
+    val pathPrefix = Some("sm")
+    val pathSuffix = Some(".sm")
+    val userType = SimpleMessageType
+  }
+
+  @Test
+  def allPaths {
+    val first = SimpleMessage("first", 1)
+    val second = SimpleMessage("second", 2)
+
+    val files = List(
+      ("sm/toBeIgnored", writeTextContent("this is to be ignored")),
+      ("sm/first.sm", writeMessage(SimpleMessageType, first)),
+      ("sm/second.sm", writeMessage(SimpleMessageType, second))
+    )
+    commit(files)
+
+    val db = new JGitDatabase(repository)
+
+    val foundFiles = db.all(SimpleMessageFileType).toList
+
+    val expected = List("sm/first.sm", "sm/second.sm")
+    assertEquals(expected, foundFiles.map(_.path))
+  }
+
+  @Test
+  def allSimpleMessages {
+    val first = SimpleMessage("first", 1)
+    val second = SimpleMessage("second", 2)
+
+    val files = List(
+      ("sm/toBeIgnored", writeTextContent("this is to be ignored")),
+      ("sm/first.sm", writeMessage(SimpleMessageType, first)),
+      ("sm/second.sm", writeMessage(SimpleMessageType, second))
+    )
+    commit(files)
+
+    val db = new JGitDatabase(repository)
+
+    val foundFiles = db.all(SimpleMessageFileType).toList
+
+    val expected = List(first, second)
+    assertEquals(expected, foundFiles.map(_.userObject))
+  }
+
+  @Test
+  def allFilterRegularFilesOnly {
+    val dc = org.spearce.jgit.dircache.DirCache.newInCore
+    val builder = dc.builder
+    val entry = new org.spearce.jgit.dircache.DirCacheEntry("sm/exec.sm")
+    entry.setFileMode(org.spearce.jgit.lib.FileMode.EXECUTABLE_FILE)
+    entry.setObjectId(writeTextContent("text content"))
+    builder.add(entry)
+    builder.finish()
+    val treeId = dc.writeTree(new org.spearce.jgit.lib.ObjectWriter(repository))
+    val commitId = createCommit("Test commit", treeId)
+    moveHEAD(commitId)
+
+    val db = new JGitDatabase(repository)
+
+    val foundFiles = db.all(SimpleMessageFileType).toList
+    assertEquals(Nil, foundFiles)
+  }
+
+  private def commit(files: List[(String, ObjectId)]) {
+    val treeId = addFiles(files)
+    val commitId = createCommit("Test", treeId)
+    moveHEAD(commitId)
+  }
+
+}