Create Bazel coverage report action.

Fixes #5246

RELNOTES: None.
PiperOrigin-RevId: 203453340

4 files changed, 58 insertions, 10 deletions

diff --git a/tools/test/BUILD b/tools/test/BUILD
index 3f7d28b72a..4a4e56b284 100644
--- a/tools/test/BUILD
+++ b/tools/test/BUILD
@@ -24,7 +24,7 @@ filegroup(
 
 filegroup(
     name = "coverage_report_generator",
-    srcs = ["//tools/coverage:coverage_report_generator"],
+    srcs = ["@bazel_tools//tools/test/LcovMerger/java/com/google/devtools/lcovmerger:Main"],
 )
 
 filegroup(
diff --git a/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/BUILD.tools b/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/BUILD.tools
index 37cf8e4657..29a60f0fef 100644
--- a/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/BUILD.tools
+++ b/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/BUILD.tools
@@ -7,6 +7,7 @@ java_import(
 
 java_binary(
   name = "Main",
+  create_executable = 1,
   main_class = "com.google.devtools.lcovmerger.Main",
   runtime_deps = [":all_lcov_merger_lib"],
 )
diff --git a/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/Main.java b/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/Main.java
index 5bac98e80d..2984d7b274 100644
--- a/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/Main.java
+++ b/tools/test/LcovMerger/java/com/google/devtools/lcovmerger/Main.java
@@ -15,12 +15,15 @@
 package com.google.devtools.lcovmerger;
 
 import static com.google.devtools.lcovmerger.LcovConstants.TRACEFILE_EXTENSION;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.annotations.VisibleForTesting;
+import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStreamReader;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -48,14 +51,23 @@ public class Main {
       System.exit(1);
     }
 
-    List<File> lcovTracefiles = getLcovTracefiles(flags.get("coverage_dir"));
+    List<File> lcovTracefiles = new ArrayList<>();
+    if (flags.containsKey("coverage_dir")) {
+      logger.log(Level.SEVERE, "Retrieving tracefiles from coverage_dir.");
+      lcovTracefiles = getLcovTracefilesFromDir(flags.get("coverage_dir"));
+    } else if (flags.containsKey("reports_file")) {
+      logger.log(Level.SEVERE, "Retrieving tracefiles from reports_file.");
+      lcovTracefiles = getLcovTracefilesFromFile(flags.get("reports_file"));
+    }
     if (lcovTracefiles.isEmpty()) {
       logger.log(Level.SEVERE, "No lcov file found.");
       System.exit(1);
     }
+    logger.log(Level.SEVERE, "Found " + lcovTracefiles.size() + " tracefiles.");
     Coverage coverage = new Coverage();
     for (File tracefile : lcovTracefiles) {
       try {
+        logger.log(Level.SEVERE, "Parsing tracefile " + tracefile.toString());
         List<SourceFileCoverage> sourceFilesCoverage =
             LcovParser.parse(new FileInputStream(tracefile));
         for (SourceFileCoverage sourceFileCoverage : sourceFilesCoverage) {
@@ -72,7 +84,8 @@ public class Main {
       File coverageFile = new File(outputFile);
       LcovPrinter.print(new FileOutputStream(coverageFile), coverage);
     } catch (IOException e) {
-      logger.log(Level.SEVERE, "Could not write to output file " + outputFile);
+      logger.log(Level.SEVERE,
+          "Could not write to output file " + outputFile + " due to " + e.getMessage());
       exitStatus = 1;
     }
     System.exit(exitStatus);
@@ -83,19 +96,37 @@ public class Main {
    * directory.
    */
   @VisibleForTesting
-  static List<File> getLcovTracefiles(String coverageDir) {
+  static List<File> getLcovTracefilesFromDir(String coverageDir) {
     List<File> datFiles = new ArrayList<>();
     try (Stream<Path> stream = Files.walk(Paths.get(coverageDir))) {
       datFiles = stream.filter(p -> p.toString().endsWith(TRACEFILE_EXTENSION))
           .map(path -> path.toFile())
           .collect(Collectors.toList());
     } catch (IOException ex) {
-      logger.log(Level.SEVERE, "error reading folder " + coverageDir + ": " + ex.getMessage());
+      logger.log(Level.SEVERE, "Error reading folder " + coverageDir + ": " + ex.getMessage());
     }
 
     return datFiles;
   }
 
+  static List<File> getLcovTracefilesFromFile(String reportsFile) {
+    List<File> datFiles = new ArrayList<>();
+    try (FileInputStream inputStream = new FileInputStream(reportsFile)) {
+      InputStreamReader inputStreamReader = new InputStreamReader(inputStream, UTF_8);
+      BufferedReader reader = new BufferedReader(inputStreamReader);
+      for (String tracefile = reader.readLine(); tracefile != null; tracefile = reader.readLine()) {
+        // TODO(elenairina): baseline coverage contains some file names that need to be modified
+        if (!tracefile.endsWith("baseline_coverage.dat")) {
+          datFiles.add(new File(tracefile));
+        }
+      }
+
+    } catch (IOException e) {
+      logger.log(Level.SEVERE, "Error reading file " + reportsFile + ": " + e.getMessage());
+    }
+    return datFiles;
+  }
+
   /**
    * Parse flags in the form of "--coverage_dir=... -output_file=..."
    */
@@ -114,12 +145,28 @@ public class Main {
     }
 
     // Validate flags
-    if (!flags.containsKey("coverage_dir")) {
-      throw new IllegalArgumentException("coverage_dir was not specified");
+    for (String flag : flags.keySet()) {
+      switch (flag) {
+        case "coverage_dir":
+        case "reports_file":
+        case "output_file":
+          continue;
+        default:
+          throw new IllegalArgumentException("Unknown flag --" + flag);
+      }
+    }
+
+    if (!flags.containsKey("coverage_dir") && !flags.containsKey("reports_file")) {
+      throw new IllegalArgumentException(
+          "At least one of --coverage_dir or --reports_file should be specified.");
+    }
+    if (flags.containsKey("coverage_dir") && flags.containsKey("reports_file")) {
+      throw new IllegalArgumentException(
+          "Only one of --coverage_dir or --reports_file must be specified.");
     }
     if (!flags.containsKey("output_file")) {
       // Different from blaze, this should be mandatory
-      throw new IllegalArgumentException("output_file was not specified");
+      throw new IllegalArgumentException("--output_file was not specified");
     }
 
     return flags;
diff --git a/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/MainTest.java b/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/MainTest.java
index 07be4215e5..a6b99fb12e 100644
--- a/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/MainTest.java
+++ b/tools/test/LcovMerger/javatests/com/google/devtools/lcovmerger/MainTest.java
@@ -41,7 +41,7 @@ public class MainTest {
 
   @Test
   public void testMainEmptyCoverageDir() {
-    assertThat(Main.getLcovTracefiles(coverageDir.toAbsolutePath().toString())).isEmpty();
+    assertThat(Main.getLcovTracefilesFromDir(coverageDir.toAbsolutePath().toString())).isEmpty();
   }
 
   @Test
@@ -52,7 +52,7 @@ public class MainTest {
     Files.createTempFile(ccCoverageDir, "tracefile1", ".dat");
     Files.createTempFile(javaCoverageDir, "tracefile2", ".dat");
 
-    List<File> tracefiles = Main.getLcovTracefiles(coverageDir.toAbsolutePath().toString());
+    List<File> tracefiles = Main.getLcovTracefilesFromDir(coverageDir.toAbsolutePath().toString());
     assertThat(tracefiles).hasSize(2);
   }
 }