InlineEdit: Add GET /changes/<id>/edit/path%2fto%2ffile REST endpoint

Add REST endpoint to retrieve file content for change edit.

Change-Id: I7df93398d057eba7d22e65b913ca9d68851ba0c9

Documentation/rest-api-changes.txt

@@ -1269,6 +1269,32 @@ When change edit doesn't exist for this change yet it is created.
   HTTP/1.1 204 No Content
 ----
 
+[[get-edit-file]]
+=== Retrieve file content from Change Edit
+--
+'GET /changes/link:#change-id[\{change-id\}]/edit/path%2fto%2ffile
+--
+
+Retrieves content of a file from a change edit.
+
+.Request
+----
+  GET /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/edit/foo HTTP/1.0
+----
+
+The content of the file is returned as text encoded inside base64. When
+specified file was deleted in the change edit "`204 No Content`" is returned.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: text/plain;charset=ISO-8859-1
+  X-FYI-Content-Encoding: base64
+
+  RnJvbSA3ZGFkY2MxNTNmZGVhMTdhYTg0ZmYzMmE2ZTI0NWRiYjY...
+----
+
 [[reviewer-endpoints]]
 == Reviewer Endpoints
 

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/BUCK

@@ -3,5 +3,8 @@ include_defs('//gerrit-acceptance-tests/tests.defs')
 acceptance_tests(
   srcs = ['ChangeEditIT.java'],
   labels = ['edit'],
-  deps = ['//lib/joda:joda-time'],
+  deps = [
+    '//lib/commons:codec',
+    '//lib/joda:joda-time',
+  ],
 )

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/ChangeEditIT.java

@@ -39,8 +39,8 @@ import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.IdentifiedUser;
-import com.google.gerrit.server.change.ChangeEdits.Put;
 import com.google.gerrit.server.change.ChangeEdits.Post;
+import com.google.gerrit.server.change.ChangeEdits.Put;
 import com.google.gerrit.server.change.FileContentUtil;
 import com.google.gerrit.server.edit.ChangeEdit;
 import com.google.gerrit.server.edit.ChangeEditModifier;
@@ -50,6 +50,8 @@ import com.google.gwtorm.server.SchemaFactory;
 import com.google.inject.Inject;
 import com.google.inject.util.Providers;
 
+import org.apache.commons.codec.binary.Base64;
+import org.apache.commons.codec.binary.StringUtils;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.RefUpdate;
@@ -428,6 +430,44 @@ public class ChangeEditIT extends AbstractDaemonTest {
             edit.get().getRevision().get(), FILE_NAME)));
   }
 
+  @Test
+  public void getFileContentRest() throws Exception {
+    Put.Input in = new Put.Input();
+    in.content = RestSession.newRawInput(CONTENT_NEW);
+    assertEquals(SC_NO_CONTENT, session.putRaw(urlEditFile(),
+        in.content).getStatusCode());
+    Optional<ChangeEdit> edit = editUtil.byChange(change);
+    assertEquals(RefUpdate.Result.FORCED,
+        modifier.modifyFile(
+            edit.get(),
+            FILE_NAME,
+            CONTENT_NEW2));
+    edit = editUtil.byChange(change);
+    RestResponse r = session.get(urlEditFile());
+    assertEquals(SC_OK, r.getStatusCode());
+    String content = r.getEntityContent();
+    assertEquals(StringUtils.newStringUtf8(CONTENT_NEW2),
+        StringUtils.newStringUtf8(Base64.decodeBase64(content)));
+  }
+
+  @Test
+  public void getFileNotFoundRest() throws Exception {
+    assertEquals(RefUpdate.Result.NEW,
+        modifier.createEdit(
+            change,
+            ps));
+    assertEquals(SC_NO_CONTENT, session.delete(urlEditFile()).getStatusCode());
+    Optional<ChangeEdit> edit = editUtil.byChange(change);
+    try {
+      fileUtil.getContent(edit.get().getChange().getProject(),
+          edit.get().getRevision().get(), FILE_NAME);
+      fail("ResourceNotFoundException expected");
+    } catch (ResourceNotFoundException rnfe) {
+    }
+    RestResponse r = session.get(urlEditFile());
+    assertEquals(SC_NO_CONTENT, r.getStatusCode());
+  }
+
   @Test
   public void addNewFile() throws Exception {
     assertEquals(RefUpdate.Result.NEW,

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeEdits.java

@@ -310,4 +310,27 @@ public class ChangeEdits implements
       return Response.none();
     }
   }
+
+  @Singleton
+  static class Get implements RestReadView<ChangeEditResource> {
+    private final FileContentUtil fileContentUtil;
+
+    @Inject
+    Get(FileContentUtil fileContentUtil) {
+      this.fileContentUtil = fileContentUtil;
+    }
+
+    @Override
+    public Response<?> apply(ChangeEditResource rsrc)
+        throws ResourceNotFoundException, IOException {
+      try {
+        return Response.ok(fileContentUtil.getContent(
+              rsrc.getChangeEdit().getChange().getProject(),
+              rsrc.getChangeEdit().getRevision().get(),
+              rsrc.getPath()));
+      } catch (ResourceNotFoundException rnfe) {
+        return Response.none();
+      }
+    }
+  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java

@@ -104,6 +104,7 @@ public class Module extends RestApiModule {
     child(CHANGE_KIND, "edit").to(ChangeEdits.class);
     put(CHANGE_EDIT_KIND, "/").to(ChangeEdits.Put.class);
     delete(CHANGE_EDIT_KIND).to(ChangeEdits.DeleteContent.class);
+    get(CHANGE_EDIT_KIND, "/").to(ChangeEdits.Get.class);
 
     install(new FactoryModule() {
       @Override