Wrap xml files in a file(system)wrapper in preprocessing

3 files changed, 72 insertions, 9 deletions

diff --git a/config-application-package/src/main/java/com/yahoo/config/application/FileSystemWrapper.java b/config-application-package/src/main/java/com/yahoo/config/application/FileSystemWrapper.java
new file mode 100644
index 00000000000..8a08c56b3c0
--- /dev/null
+++ b/config-application-package/src/main/java/com/yahoo/config/application/FileSystemWrapper.java
@@ -0,0 +1,50 @@
+package com.yahoo.config.application;
+
+import com.yahoo.yolean.function.ThrowingFunction;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
+import java.util.function.Predicate;
+
+/**
+ * Wraps a real or virtual file system — essentially a mapping from paths to bytes.
+ *
+ * @author jonmv
+ */
+public class FileSystemWrapper {
+
+    Predicate<Path> existence;
+    ThrowingFunction<Path, byte[], IOException> reader;
+
+    private FileSystemWrapper(Predicate<Path> existence, ThrowingFunction<Path, byte[], IOException> reader) {
+        this.existence = existence;
+        this.reader = reader;
+    }
+
+    public static FileSystemWrapper ofFiles(Predicate<Path> existence, ThrowingFunction<Path, byte[], IOException> reader) {
+        return new FileSystemWrapper(existence, reader);
+    }
+
+    public static FileSystemWrapper getDefault() {
+        return ofFiles(Files::exists, Files::readAllBytes);
+    }
+
+    public FileWrapper wrap(Path path) {
+        return new FileWrapper(path);
+    }
+
+
+    public class FileWrapper {
+        private final Path path;
+        private FileWrapper(Path path) { this.path = path; }
+
+        public Path path() { return path; }
+        public boolean exists() { return existence.test(path); }
+        public byte[] content() throws IOException { return reader.apply(path); }
+        public Optional<FileWrapper> parent() { return Optional.ofNullable(path.getParent()).map(path -> wrap(path)); }
+        public FileWrapper child(String name) { return wrap(path.resolve(name)); }
+    }
+
+}
diff --git a/config-application-package/src/main/java/com/yahoo/config/application/IncludeProcessor.java b/config-application-package/src/main/java/com/yahoo/config/application/IncludeProcessor.java
index c2da2a55b48..b09953c738c 100644
--- a/config-application-package/src/main/java/com/yahoo/config/application/IncludeProcessor.java
+++ b/config-application-package/src/main/java/com/yahoo/config/application/IncludeProcessor.java
@@ -1,7 +1,7 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.application;
 
-import com.yahoo.io.IOUtils;
+import com.yahoo.config.application.FileSystemWrapper.FileWrapper;
 import com.yahoo.text.XML;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
@@ -14,6 +14,9 @@ import java.io.IOException;
 import java.io.StringReader;
 import java.io.StringWriter;
 import java.util.List;
+import java.util.NoSuchElementException;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 /**
  * Handles preprocess:include statements and returns a Document which has all the include statements resolved
@@ -23,10 +26,14 @@ import java.util.List;
  */
 class IncludeProcessor implements PreProcessor {
 
-    private final File application;
+    private final FileWrapper application;
+
     public IncludeProcessor(File application) {
-        this.application = application;
+        this(FileSystemWrapper.getDefault().wrap(application.toPath()));
+    }
 
+    public IncludeProcessor(FileWrapper application) {
+        this.application = application;
     }
 
     public Document process(Document input) throws IOException, TransformerException {
@@ -35,17 +42,18 @@ class IncludeProcessor implements PreProcessor {
         return doc;
     }
 
-    private static void includeFile(File currentFolder, Element currentElement) throws IOException {
+    private static void includeFile(FileWrapper currentFolder, Element currentElement) throws IOException {
         NodeList list = currentElement.getElementsByTagNameNS(XmlPreProcessor.preprocessNamespaceUri, "include");
         while (list.getLength() > 0) {
             Element elem = (Element) list.item(0);
             Element parent = (Element) elem.getParentNode();
             String filename = elem.getAttribute("file");
             boolean required = ! elem.hasAttribute("required") || Boolean.parseBoolean(elem.getAttribute("required"));
-            File file = new File(currentFolder, filename);
+            FileWrapper file = currentFolder.child(filename);
 
             Document subFile = IncludeProcessor.parseIncludeFile(file, parent.getTagName(), required);
-            includeFile(file.getParentFile(), subFile.getDocumentElement());
+            includeFile(file.parent().orElseThrow(() -> new NoSuchElementException(file + " has no parent")),
+                        subFile.getDocumentElement());
 
             //System.out.println("document before merging: " + documentAsString(doc));
             IncludeProcessor.mergeInto(parent, XML.getChildren(subFile.getDocumentElement()));
@@ -65,12 +73,12 @@ class IncludeProcessor implements PreProcessor {
         }
     }
 
-    private static Document parseIncludeFile(File file, String parentTagName, boolean required) throws IOException {
+    private static Document parseIncludeFile(FileWrapper file, String parentTagName, boolean required) throws IOException {
         StringWriter w = new StringWriter();
         final String startTag = "<" + parentTagName + " " + XmlPreProcessor.deployNamespace + "='" + XmlPreProcessor.deployNamespaceUri + "' " + XmlPreProcessor.preprocessNamespace + "='" + XmlPreProcessor.preprocessNamespaceUri + "'>";
         w.append(startTag);
         if (file.exists() || required) {
-            w.append(IOUtils.readFile(file));
+            w.append(new String(file.content(), UTF_8));
         }
         final String endTag = "</" + parentTagName + ">";
         w.append(endTag);
diff --git a/config-application-package/src/main/java/com/yahoo/config/application/XmlPreProcessor.java b/config-application-package/src/main/java/com/yahoo/config/application/XmlPreProcessor.java
index c49a799f2b7..61b67dfb5c6 100644
--- a/config-application-package/src/main/java/com/yahoo/config/application/XmlPreProcessor.java
+++ b/config-application-package/src/main/java/com/yahoo/config/application/XmlPreProcessor.java
@@ -1,6 +1,7 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.application;
 
+import com.yahoo.config.application.FileSystemWrapper.FileWrapper;
 import com.yahoo.config.provision.Environment;
 import com.yahoo.config.provision.InstanceName;
 import com.yahoo.config.provision.RegionName;
@@ -31,7 +32,7 @@ public class XmlPreProcessor {
     final static String preprocessNamespace = "xmlns:preprocess";
     final static String preprocessNamespaceUri = "properties";  //TODO
 
-    private final File applicationDir;
+    private final FileWrapper applicationDir;
     private final Reader xmlInput;
     private final InstanceName instance;
     private final Environment environment;
@@ -43,6 +44,10 @@ public class XmlPreProcessor {
     }
 
     public XmlPreProcessor(File applicationDir, Reader xmlInput, InstanceName instance, Environment environment, RegionName region) {
+        this(FileSystemWrapper.getDefault().wrap(applicationDir.toPath()), xmlInput, instance, environment, region);
+    }
+
+    public XmlPreProcessor(FileWrapper applicationDir, Reader xmlInput, InstanceName instance, Environment environment, RegionName region) {
         this.applicationDir = applicationDir;
         this.xmlInput = xmlInput;
         this.instance = instance;