Open-source JavaToolchainDataParser

JavaToolchainDataParser is a parser that reconstruct a JavaToolchainData from the output of a 'bazel query --output=proto'.

--
MOS_MIGRATED_REVID=87502754

src/main/java/BUILD

diff --git a/src/main/java/BUILD b/src/main/java/BUILD
index 30c1a35..b78e832 100644
--- a/src/main/java/BUILD
+++ b/src/main/java/BUILD
@@ -9,7 +9,10 @@
     name = "bazel-core",
     srcs = glob(
         ["**/*.java"],
-        exclude = ["com/google/devtools/build/lib/shell/*.java"],
+        exclude = [
+            "com/google/devtools/build/lib/shell/*.java",
+            "com/google/devtools/build/lib/rules/java/JavaToolchainDataParser.java",
+        ],
     ),
     resources = glob([
         "**/*.txt",
@@ -47,6 +50,28 @@
     ],
 )
 
+java_library(
+    name = "java-toolchain-parser",
+    testonly = 1,
+    srcs = glob([
+        # JavaToolchain parser
+        "com/google/devtools/build/lib/rules/java/JavaToolchainData.java",
+        "com/google/devtools/build/lib/rules/java/JavaToolchainDataParser.java",
+        # Concurrent stuff
+        "com/google/devtools/build/lib/concurrent/*.java",
+        "com/google/devtools/build/lib/Constants.java",
+    ]),
+    visibility = [
+        "//src/test:__subpackages__",
+    ],
+    deps = [
+        "//src/main/protobuf:proto_build",
+        "//third_party:guava",
+        "//third_party:jsr305",
+        "//third_party:protobuf",
+    ],
+)
+
 java_binary(
     name = "bazel-main",
     main_class = "com.google.devtools.build.lib.bazel.BazelMain",

src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainDataParser.java

diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainDataParser.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainDataParser.java
new file mode 100644
index 0000000..64e1eb3
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaToolchainDataParser.java
@@ -0,0 +1,99 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.build.lib.rules.java;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.query2.proto.proto2api.Build;
+import com.google.devtools.build.lib.query2.proto.proto2api.Build.QueryResult;
+import com.google.protobuf.TextFormat;
+import com.google.protobuf.TextFormat.ParseException;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A class to parse a {@link JavaToolchainData} from the result of blaze query. It is used by
+ * {@link com.google.devtools.build.java.bazel.BazelJavaCompiler} to get default options.
+ */
+public class JavaToolchainDataParser {
+
+  /**
+   * Parse a {@link com.google.devtools.build.lib.query2.proto.proto2api.Build.QueryResult} as
+   * returned by a bazel query and look for the list of target containing a {@code java_toolchain}
+   * rule. These rules are then parsed into {@link JavaToolchainData}'s and returned as map with the
+   * name of the target as key and the {@link JavaToolchainData} as value.
+   */
+  public static ImmutableMap<String, JavaToolchainData> parse(QueryResult queryResult) {
+    ImmutableMap.Builder<String, JavaToolchainData> builder = ImmutableMap.builder();
+    for (Build.Target target : queryResult.getTargetList()) {
+      Build.Rule rule = target.getRule();
+      if (target.hasRule() && rule.getRuleClass().equals("java_toolchain")) {
+        builder.put(rule.getName(), parseBuildRuleProto(rule));
+      }
+    }
+    return builder.build();
+  }
+
+  /**
+   * Parse a text serialization of a
+   * {@link com.google.devtools.build.lib.query2.proto.proto2api.Build.QueryResult}. See
+   * {@link #parse(QueryResult)} for the details of the result.
+   *
+   * @throws ParseException when the provided string does not corresponds to a bazel query output.
+   */
+  public static ImmutableMap<String, JavaToolchainData> parse(String queryResult)
+      throws ParseException {
+    QueryResult.Builder builder = QueryResult.newBuilder();
+    TextFormat.merge(queryResult, builder);
+    return parse(builder.build());
+  }
+  /**
+   * Parse a {@link com.google.devtools.build.lib.query2.proto.proto2api.Build.QueryResult} from
+   * an input stream. See {@link #parse(QueryResult)} for the details of the result.
+   */
+  public static ImmutableMap<String, JavaToolchainData> parse(InputStream queryResult)
+      throws IOException {
+    return parse(QueryResult.newBuilder().mergeFrom(queryResult).build());
+  }
+
+  private static JavaToolchainData parseBuildRuleProto(Build.Rule rule) {
+    String source = "";
+    String target = "";
+    String encoding = "";
+    ImmutableList<String> xlint = ImmutableList.of();
+    ImmutableList<String> misc = ImmutableList.of();
+    for (Build.Attribute attribute : rule.getAttributeList()) {
+      switch (attribute.getName()) {
+        case "source_version":
+          source = attribute.getStringValue();
+          break;
+        case "target_version":
+          target = attribute.getStringValue();
+          break;
+        case "encoding":
+          encoding = attribute.getStringValue();
+          break;
+        case "xlint":
+          xlint = ImmutableList.copyOf(attribute.getStringListValueList());
+          break;
+        case "misc":
+          misc = ImmutableList.copyOf(attribute.getStringListValueList());
+          break;
+      }
+    }
+    return new JavaToolchainData(source, target, encoding, xlint, misc);
+  }
+}