Fix #16: NPE on unterminated ifdef.

3 files changed, 55 insertions, 15 deletions

diff --git a/src/main/java/org/anarres/cpp/MacroTokenSource.java b/src/main/java/org/anarres/cpp/MacroTokenSource.java
index 516e4f2..92317eb 100644
--- a/src/main/java/org/anarres/cpp/MacroTokenSource.java
+++ b/src/main/java/org/anarres/cpp/MacroTokenSource.java
@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
 
+import javax.annotation.Nonnull;
 import static org.anarres.cpp.Token.*;
 
 /* This source should always be active, since we don't expand macros
@@ -50,7 +51,11 @@ import static org.anarres.cpp.Token.*;
     }
 
     /* XXX Called from Preprocessor [ugly]. */
-    /* pp */ static void escape(StringBuilder buf, CharSequence cs) {
+    /* pp */ static void escape(@Nonnull StringBuilder buf, @Nonnull CharSequence cs) {
+        if (buf == null)
+            throw new NullPointerException("Buffer was null.");
+        if (cs == null)
+            throw new NullPointerException("CharSequence was null.");
         for (int i = 0; i < cs.length(); i++) {
             char c = cs.charAt(i);
             switch (c) {
diff --git a/src/main/java/org/anarres/cpp/Preprocessor.java b/src/main/java/org/anarres/cpp/Preprocessor.java
index 0ad1538..f96eb4a 100644
--- a/src/main/java/org/anarres/cpp/Preprocessor.java
+++ b/src/main/java/org/anarres/cpp/Preprocessor.java
@@ -495,6 +495,7 @@ public class Preprocessor implements Closeable {
      * @see #push_source(Source,boolean)
      * @see #pop_source()
      */
+    @CheckForNull
     protected Source getSource() {
         return source;
     }
@@ -552,18 +553,30 @@ public class Preprocessor implements Closeable {
         pop_source(false);
     }
 
+    @Nonnull
+    private Token next_source() {
+        if (inputs.isEmpty())
+            return new Token(EOF);
+        Source s = inputs.remove(0);
+        push_source(s, true);
+        return line_token(s.getLine(), s.getName(), " 1");
+    }
+
     /* Source tokens */
     private Token source_token;
 
     /* XXX Make this include the NL, and make all cpp directives eat
      * their own NL. */
     @Nonnull
-    private Token line_token(int line, String name, String extra) {
+    private Token line_token(int line, @CheckForNull String name, @Nonnull String extra) {
         StringBuilder buf = new StringBuilder();
         buf.append("#line ").append(line)
                 .append(" \"");
         /* XXX This call to escape(name) is correct but ugly. */
-        MacroTokenSource.escape(buf, name);
+        if (name == null)
+            buf.append("<unnamed-source>");
+        else
+            MacroTokenSource.escape(buf, name);
         buf.append("\"").append(extra).append("\n");
         return new Token(P_LINE, line, 0, buf.toString(), null);
     }
@@ -583,13 +596,10 @@ public class Preprocessor implements Closeable {
         for (;;) {
             Source s = getSource();
             if (s == null) {
-                if (inputs.isEmpty())
-                    return new Token(EOF);
-                Source t = inputs.remove(0);
-                push_source(t, true);
-                if (getFeature(Feature.LINEMARKERS))
-                    return line_token(t.getLine(), t.getName(), " 1");
-                continue;
+                Token t = next_source();
+                if (t.getType() == P_LINE && !getFeature(Feature.LINEMARKERS))
+                    continue;
+                return t;
             }
             Token tok = s.token();
             /* XXX Refactor with skipline() */
@@ -1675,13 +1685,21 @@ public class Preprocessor implements Closeable {
         for (;;) {
             Token tok;
             if (!isActive()) {
+                Source s = getSource();
+                if (s == null) {
+                    Token t = next_source();
+                    if (t.getType() == P_LINE && !getFeature(Feature.LINEMARKERS))
+                        continue;
+                    return t;
+                }
+
                 try {
                     /* XXX Tell lexer to ignore warnings. */
-                    source.setActive(false);
+                    s.setActive(false);
                     tok = source_token();
                 } finally {
                     /* XXX Tell lexer to stop ignoring warnings. */
-                    source.setActive(true);
+                    s.setActive(true);
                 }
                 switch (tok.getType()) {
                     case HASH:
diff --git a/src/test/java/org/anarres/cpp/PreprocessorTest.java b/src/test/java/org/anarres/cpp/PreprocessorTest.java
index c8bd7a1..7103cba 100644
--- a/src/test/java/org/anarres/cpp/PreprocessorTest.java
+++ b/src/test/java/org/anarres/cpp/PreprocessorTest.java
@@ -4,6 +4,8 @@ import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.PipedInputStream;
 import java.io.PipedOutputStream;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.junit.Before;
 import org.junit.Test;
 import static org.anarres.cpp.Token.*;
@@ -11,6 +13,8 @@ import static org.junit.Assert.*;
 
 public class PreprocessorTest {
 
+    private static final Log LOG = LogFactory.getLog(PreprocessorTest.class);
+
     private OutputStreamWriter writer;
     private Preprocessor p;
 
@@ -153,18 +157,31 @@ public class PreprocessorTest {
         Token t;
         do {
             t = p.token();
-            System.out.println("Remaining token " + t);
+            LOG.warn("Remaining token " + t);
+        } while (t.getType() != EOF);
+    }
+
+    @Test
+    public void testPreprocessorUnterminated() throws Exception {
+        testInput("#ifndef X\na\n#else\nb\n");   // Bug #16
+
+        writer.close();
+
+        Token t;
+        do {
+            t = p.token();
+            LOG.warn("Remaining token " + t);
         } while (t.getType() != EOF);
     }
 
     private void testInput(String in, Object... out)
             throws Exception {
-        System.out.print("Input: " + in);
+        LOG.info("Input: " + in);
         writer.write(in);
         writer.flush();
         for (int i = 0; i < out.length; i++) {
             Token t = p.token();
-            System.out.println(t);
+            LOG.info(t);
             Object v = out[i];
             if (v instanceof String) {
                 if (t.getType() != STRING)