markdown/pagemodel: Only parse the Multimarkdown metadata if there ar…

…e valid

Prior to this change, metadata were parsed even if the metadata block
was not valid.

Example of non valid metadata block:
---------
Author: Olivier
---------

The MultiMarkdown format requires an empty line to be added at the
end of the metadata block.

plugin/src/winterwell/markdown/pagemodel/MarkdownPage.java

@@ -266,28 +266,59 @@ private void setText(String text) {
 			// ends with the first whitespace only line. The metadata is
 			// stripped from the
 			// document before it is passed on to the syntax parser.
-			String data = "";
-			String tag = "";
-			for (; lineNum < lines.size(); lineNum++) {
+
+			//
+			// Check if the Metdatas are valid
+			//
+			boolean validMetadata = true;
+			for (lineNum = 0; lineNum < lines.size(); lineNum++) {
 				String line = lines.get(lineNum);
 				if (Utils.isBlank(line)) {
 					break;
 				}
 				Matcher m = multiMarkdownTag.matcher(line);
 				if (!m.find()) {
-					if (lineNum == 0)
+					if (lineNum == 0) {
+						// No MultiMarkdown metadata
+						validMetadata = false;
+						break;
+					} else if (!line.matches("^\\s.*\n")) {
+						// The next line was not intended (ie. it does not start
+						// with a whitespace)
+						validMetadata = false;
+						break;
+					}
+				}
+			}
+
+			// Valid Metadatas have been found. We need to retrieve these keys/values.
+			if (validMetadata) {
+				String data = "";
+				String tag = "";
+				for (lineNum = 0; lineNum < lines.size(); lineNum++) {
+					String line = lines.get(lineNum);
+					if (Utils.isBlank(line)) {
 						break;
-					// Multi-line tag
-					lineTypes.add(KLineType.META);
-					data += StrUtils.LINEEND + line.trim();
-					multiMarkdownTags.put(tag, data);
-				} else {
-					lineTypes.add(KLineType.META);
-					tag = m.group(0);
-					data = m.group(1).trim();
-					if (m.group(1).endsWith(line))
+					}
+					Matcher m = multiMarkdownTag.matcher(line);
+					if (!m.find()) {
+						if (lineNum == 0) {
+							break;
+						}
+						// Multi-line tag
+						lineTypes.add(KLineType.META);
+						data += StrUtils.LINEEND + line.trim();
 						multiMarkdownTags.put(tag, data);
+					} else {
+						lineTypes.add(KLineType.META);
+						tag = m.group(0);
+						data = m.group(1).trim();
+						if (m.group(1).endsWith(line))
+							multiMarkdownTags.put(tag, data);
+					}
 				}
+			} else {
+				lineNum = 0;
 			}
 		}
 		for (; lineNum < lines.size(); lineNum++) {