Split out path relative file reader

1 files changed, 45 insertions, 0 deletions

diff --git a/src/main/java/org/zwobble/mammoth/internal/docx/PathRelativeFileReader.java b/src/main/java/org/zwobble/mammoth/internal/docx/PathRelativeFileReader.java
new file mode 100644
index 0000000..ebee416
--- /dev/null
+++ b/src/main/java/org/zwobble/mammoth/internal/docx/PathRelativeFileReader.java
@@ -0,0 +1,45 @@
+package org.zwobble.mammoth.internal.docx;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.file.Path;
+import java.util.Optional;
+
+public class PathRelativeFileReader implements FileReader {
+    private final Optional<Path> path;
+
+    public PathRelativeFileReader(Optional<Path> path) {
+        this.path = path;
+    }
+
+    @Override
+    public InputStream getInputStream(String uri) throws IOException {
+        try {
+            Optional<URI> absoluteUri = asAbsoluteUri(uri);
+            if (absoluteUri.isPresent()) {
+                return open(absoluteUri.get());
+            } else if (path.isPresent()) {
+                return open(path.get().toUri().resolve(uri));
+            } else {
+                throw new IOException("path of document is unknown, but is required for relative URI");
+            }
+        } catch (IOException exception) {
+            throw new IOException("could not open external image '" + uri + "': " + exception.getMessage());
+        }
+    }
+
+    private static InputStream open(URI uri) throws IOException {
+        return uri.toURL().openStream();
+    }
+
+    private static Optional<URI> asAbsoluteUri(String uriString) {
+        try {
+            URI uri = new URI(uriString);
+            return uri.isAbsolute() ? Optional.of(uri) : Optional.empty();
+        } catch (URISyntaxException exception) {
+            return Optional.empty();
+        }
+    }
+}