Fix javac --incremental by using jmake for dependency analysis

third_party/jmake/src/org/pantsbuild/jmake/TextProjectDatabaseReader.java

Index: third_party/jmake/src/org/pantsbuild/jmake/TextProjectDatabaseReader.java
diff --git a/third_party/jmake/src/org/pantsbuild/jmake/TextProjectDatabaseReader.java b/third_party/jmake/src/org/pantsbuild/jmake/TextProjectDatabaseReader.java
new file mode 100644
index 0000000000000000000000000000000000000000..d227a8eba8e1b9ac7649afca06aa1be6aff2555f
--- /dev/null
+++ b/third_party/jmake/src/org/pantsbuild/jmake/TextProjectDatabaseReader.java
@@ -0,0 +1,107 @@
+/* Copyright (c) 2002-2013 Sun Microsystems, Inc. All rights reserved
+ *
+ * This program is distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+package org.pantsbuild.jmake;
+
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.ObjectInputStream;
+import java.io.UnsupportedEncodingException;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+
+/**
+ * This class creates the internal representation of the project database from a text buffer.
+ *
+ * The Pants build tool manipulates this data in various ways, and it's easiest for it
+ * to do so by parsing text files directly.  This brings JMake into line with Zinc (the
+ * Scala incremental compiler) and allows Pants to handle both uniformly.
+ *
+ * @author  Benjy Weinberger
+ * 13 January 2013
+ */
+public class TextProjectDatabaseReader {
+    public Map<String,PCDEntry> readProjectDatabaseFromFile(File infile) {
+        try {
+            BufferedReader in =
+                new BufferedReader(new InputStreamReader(new FileInputStream(infile), "UTF-8"));
+            try {
+                return readProjectDatabase(in);
+            } finally {
+                in.close();
+            }
+        } catch (FileNotFoundException e) {
+            throw new PrivateException(e);
+        } catch (UnsupportedEncodingException e) {
+            throw new PrivateException(e);
+        } catch (IOException e) {
+            throw new PrivateException(e);
+        }
+    }
+
+    public Map<String,PCDEntry> readProjectDatabase(BufferedReader in) {
+        Map<String,PCDEntry> pcd;
+        try {
+            String line = in.readLine();
+            if (!"pcd entries:".equals(line))
+                throw error("Expected: 'pcd entries:', got: " + line);
+            line = in.readLine();
+            Matcher m = Pattern.compile("^(\\d+) items$").matcher(line);
+            if (!m.matches())
+                throw error("Expected: '<n> items', got: " + line);
+            int numEntries = Integer.parseInt(m.group(1));
+            pcd = new LinkedHashMap<String, PCDEntry>(numEntries);
+            for (int i = 0; i < numEntries; i++) {
+                line = in.readLine();
+                if (line == null)
+                    throw error("Unexpected EOF");
+                String[] parts = line.split("\t");
+                if (parts.length != 5) {
+                    throw error("Invalid line: " + line);
+                }
+                String className = parts[0];
+                String javaFullFilePath = parts[1];
+                long oldClassFileLastModified = Long.parseLong(parts[2]);
+                long oldClassFileFingerprint = Long.parseLong(parts[3]);
+                ClassInfo ci = classInfoFromBase64(parts[4]);
+                PCDEntry entry = new PCDEntry(className, javaFullFilePath, oldClassFileLastModified,
+                    oldClassFileFingerprint, ci);
+                pcd.put(entry.className, entry);
+            }
+            // We're done: We have detailed dep information in the PCD entries, so we don't
+            // need to read the dep information lines from the file.
+        } catch (IOException e) {
+            throw new PrivateException(e);
+        }
+        return pcd;
+    }
+
+    private PrivateException error(String msg) {
+        return new PrivateException(new IllegalArgumentException(msg));
+    }
+
+    private ClassInfo classInfoFromBase64(String s) {
+        try {
+            byte[] bytes = Base64.decode(s.toCharArray());
+            ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(bytes));
+            ClassInfo ret = (ClassInfo)ois.readObject();
+            ret.initializeImmediateTransientFields();
+            return ret;
+        } catch (IOException e) {
+            throw new PrivateException(e);
+        } catch (ClassNotFoundException e) {
+            throw new PrivateException(e);
+        }
+    }
+}