[Infer][annotations] Adding basic annotation processor for SuppressWarnings

Summary:
Setting up a basic annotation processor. Right now, the processor
just saves a map of class -> methods that should be suppressed. Next, this map
needs to be turned into a .inferconfig file.

infer/annotations/BUCK

@@ -1,7 +1,15 @@
 prebuilt_jar(
-    name = 'annotations',
-    binary_jar = 'annotations.jar',
-    visibility = [
-        'PUBLIC',
-    ]
+  name = 'annotations',
+  binary_jar = 'annotations.jar',
+  visibility = [
+    'PUBLIC',
+  ]
+)
+
+prebuilt_jar(
+  name = 'processor',
+  binary_jar = 'processor.jar',
+  visibility = [
+    'PUBLIC',
+  ]
 )

infer/annotations/Makefile

@@ -1,13 +1,24 @@
 DEPENDENCIES = ../../dependencies
 JSR_JAR = $(DEPENDENCIES)/java/jsr-305/jsr305.jar
-CLASSES_OUT = classes
-SOURCES = `find . -name "*.java"`
+ANNOT_SOURCES = `find com/facebook/infer/annotation -name "*.java"`
+PROCESSOR_SOURCES = `find com/facebook/infer/annotprocess -name "*.java"`
+ANNOT_CLASSES = 'annot_classes'
+PROCESSOR_CLASSES = 'processor_classes'
 
-all:
-	mkdir -p classes
-	javac -cp $(JSR_JAR) $(SOURCES)
-	jar cvf annotations.jar $(SOURCES) `find . -name "*.class"`
+all: annotations processor
+
+annotations:
+	mkdir -p $(ANNOT_CLASSES)
+	javac -cp $(JSR_JAR) $(ANNOT_SOURCES) -d $(ANNOT_CLASSES)
+	cd $(ANNOT_CLASSES) && jar cvf annotations.jar com && cp annotations.jar ../
+
+processor:
+	mkdir -p $(PROCESSOR_CLASSES)
+	javac $(PROCESSOR_SOURCES) -d $(PROCESSOR_CLASSES)
+	cd $(PROCESSOR_CLASSES) && cp -r ../resources/META-INF . && jar cvMf processor.jar com META-INF && cp processor.jar ../
 
 clean:
-	rm -rvf `find . -name "*.class"`
-	rm -rvf annotations.jar
+	rm -r $(ANNOT_CLASSES)
+	rm annotations.jar
+	rm -r $(PROCESSOR_CLASSES)
+	rm processor.jar

infer/annotations/com/facebook/infer/annotprocess/AnnotationProcessor.java

@@ -0,0 +1,56 @@
+/*
+* Copyright (c) 2015 - present Facebook, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the BSD style license found in the
+* LICENSE file in the root directory of this source tree. An additional grant
+* of patent rights can be found in the PATENTS file in the same directory.
+*/
+
+package com.facebook.infer.annotprocess;
+
+import javax.annotation.processing.*;
+import javax.lang.model.element.*;
+import javax.tools.*;
+import javax.lang.model.SourceVersion;
+import java.util.*;
+
+@SupportedAnnotationTypes({"java.lang.SuppressWarnings"})
+public class AnnotationProcessor extends AbstractProcessor {
+
+  // map of (classes -> methods in class). an empty set means suppress all warnings on class
+  public Map<String,Set<String>> suppressMap = new LinkedHashMap<String,Set<String>>();
+
+  public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment env) {
+    for (TypeElement te : annotations) {
+      for (Element e : env.getElementsAnnotatedWith(te)) {
+        if (e instanceof TypeElement) { // class
+          String className = ((TypeElement) e).getQualifiedName().toString();
+          suppressMap.put(className, Collections.EMPTY_SET);
+        } else if (e instanceof ExecutableElement) { // method
+          String clazz = e.getEnclosingElement().toString();
+          Set<String> suppressMethods = suppressMap.get(clazz);
+          if (suppressMethods == null) {
+            suppressMethods = new LinkedHashSet();
+            suppressMap.put(clazz, suppressMethods);
+          } else if (suppressMethods.isEmpty()) {
+            // empty set means suppress warnings on all methods in class; do nothing
+            continue;
+          }
+          suppressMethods.add(clazz);
+        }
+      }
+    }
+
+    if (env.processingOver()) {
+      // TODO: write suppressMap to a .inferconfig file on disk
+    }
+    return false;
+  }
+
+  @Override
+  public SourceVersion getSupportedSourceVersion() {
+    return SourceVersion.latestSupported();
+  }
+
+}

infer/annotations/resources/META-INF/services/javax.annotation.processing.Processor

@@ -0,0 +1 @@
+com.facebook.infer.annotprocess.AnnotationProcessor