Keep the original source map's sourcesContent from the input source map.

This allows the users to see the original file before an external compilation
step, typically keep the TypeScript source before it was translated to JS.

When a closure compiler is run with apply_input_source_maps and
source_map_input_content, it now preserves the original sourcesContent for the
files from the input source maps in the output source map.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=196936917

src/com/google/debugging/sourcemap/SourceMapConsumerV3.java

@@ -43,6 +43,7 @@ public final class SourceMapConsumerV3 implements SourceMapConsumer,
   static final int UNMAPPED = -1;
 
   private String[] sources;
+  private String[] sourcesContent;
   private String[] names;
   private int lineCount;
   // Slots in the lines list will be null if the line does not have any entries.
@@ -92,6 +93,7 @@ void parse(SourceMapObject sourceMapObject, SourceMapSupplier sectionSupplier)
     lineCount = sourceMapObject.getLineCount();
     sourceRoot = sourceMapObject.getSourceRoot();
     sources = sourceMapObject.getSources();
+    sourcesContent = sourceMapObject.getSourcesContent();
     names = sourceMapObject.getNames();
 
     if (lineCount >= 0) {
@@ -186,6 +188,10 @@ public Collection<String> getOriginalSources() {
     return Arrays.asList(sources);
   }
 
+  public Collection<String> getOriginalSourcesContent() {
+    return sourcesContent == null ? null : Arrays.asList(sourcesContent);
+  }
+
   @Override
   public Collection<OriginalMapping> getReverseMapping(String originalFile,
       int line, int column) {

src/com/google/debugging/sourcemap/SourceMapGeneratorV3.java

@@ -342,10 +342,11 @@ public void mergeMapSection(int line, int column, String mapSectionContents,
    * 4.    lineCount: 2,
    * 5.    sourceRoot: "",
    * 6.    sources: ["foo.js", "bar.js"],
-   * 7.    names: ["src", "maps", "are", "fun"],
-   * 8.    mappings: "a;;abcde,abcd,a;"
-   * 9.    x_org_extension: value
-   * 10. }
+   * 7.    sourcesContent: ["var foo", "var bar"],
+   * 8.    names: ["src", "maps", "are", "fun"],
+   * 9.    mappings: "a;;abcde,abcd,a;"
+   * 10.   x_org_extension: value
+   * 11. }
    *
    * Line 1: The entire file is a single JSON object
    * Line 2: File revision (always the first entry in the object)
@@ -355,10 +356,11 @@ public void mergeMapSection(int line, int column, String mapSectionContents,
    *     server or removing repeated prefix values in the "sources" entry.
    * Line 6: A list of sources used by the "mappings" entry relative to the
    *     sourceRoot.
-   * Line 7: A list of symbol names used by the "mapping" entry.  This list
+   * Line 7: An optional list of the full content of the source files.
+   * Line 8: A list of symbol names used by the "mapping" entry.  This list
    *     may be incomplete.
-   * Line 8: The mappings field.
-   * Line 9: Any custom field (extension).
+   * Line 9: The mappings field.
+   * Line 10: Any custom field (extension).
    */
   @Override
   public void appendTo(Appendable out, String name) throws IOException {

src/com/google/debugging/sourcemap/SourceMapObject.java

@@ -27,6 +27,7 @@ public class SourceMapObject {
   private final String file;
   private final String mappings;
   private final String[] sources;
+  private final String[] sourcesContent;
   private final String[] names;
   private final List<SourceMapSection> sections;
   private final Map<String, Object> extensions;
@@ -38,6 +39,7 @@ private SourceMapObject(
       String file,
       String mappings,
       String[] sources,
+      String[] sourcesContent,
       String[] names,
       List<SourceMapSection> sections,
       Map<String, Object> extensions) {
@@ -47,6 +49,7 @@ private SourceMapObject(
     this.file = file;
     this.mappings = mappings;
     this.sources = sources;
+    this.sourcesContent = sourcesContent;
     this.names = names;
     this.sections = sections;
     this.extensions = extensions;
@@ -76,6 +79,10 @@ public String[] getSources() {
     return sources;
   }
 
+  public String[] getSourcesContent() {
+    return sourcesContent;
+  }
+
   public String[] getNames() {
     return names;
   }
@@ -99,6 +106,7 @@ static class Builder {
     private String file;
     private String mappings;
     private String[] sources;
+    private String[] sourcesContent;
     private String[] names;
     private List<SourceMapSection> sections;
     private Map<String, Object> extensions;
@@ -133,6 +141,11 @@ public Builder setSources(String[] sources) {
       return this;
     }
 
+    public Builder setSourcesContent(String[] sourcesContent) {
+      this.sourcesContent = sourcesContent;
+      return this;
+    }
+
     public Builder setNames(String[] names) {
       this.names = names;
       return this;
@@ -150,7 +163,16 @@ public Builder setExtensions(Map<String, Object> extensions) {
 
     public SourceMapObject build() {
       return new SourceMapObject(
-          version, lineCount, sourceRoot, file, mappings, sources, names, sections, extensions);
+          version,
+          lineCount,
+          sourceRoot,
+          file,
+          mappings,
+          sources,
+          sourcesContent,
+          names,
+          sections,
+          extensions);
     }
   }
 }

src/com/google/debugging/sourcemap/SourceMapObjectParser.java

@@ -52,6 +52,7 @@ public static SourceMapObject parse(String contents) throws SourceMapParseExcept
       }
 
       builder.setSources(getJavaStringArray(sourceMapRoot.get("sources")));
+      builder.setSourcesContent(getJavaStringArray(sourceMapRoot.get("sourcesContent")));
       builder.setNames(getJavaStringArray(sourceMapRoot.get("names")));
 
       Map<String, Object> extensions = new LinkedHashMap<>();

src/com/google/javascript/jscomp/Compiler.java

@@ -69,6 +69,7 @@
 import java.io.Serializable;
 import java.util.AbstractSet;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -527,6 +528,11 @@ public void initBasedOnOptions() {
       sourceMap.setPrefixMappings(options.sourceMapLocationMappings);
       if (options.applyInputSourceMaps) {
         sourceMap.setSourceFileMapping(this);
+        if (options.sourceMapIncludeSourcesContent) {
+          for (SourceMapInput inputSourceMap : inputSourceMaps.values()) {
+            addSourceMapSourceFiles(inputSourceMap);
+          }
+        }
       }
     }
   }
@@ -2870,6 +2876,34 @@ public CharSequence getSourceFileContentByName(String sourceName) {
   @Override
   public void addInputSourceMap(String sourceFileName, SourceMapInput inputSourceMap) {
     inputSourceMaps.put(sourceFileName, inputSourceMap);
+    if (options.sourceMapIncludeSourcesContent) {
+      addSourceMapSourceFiles(inputSourceMap);
+    }
+  }
+
+  /**
+   * Adds file name to content mappings for all sources found in a source map.
+   * This is used to populate sourcesContent array in the output source map
+   * even for sources embedded in the input source map.
+   */
+  private void addSourceMapSourceFiles(SourceMapInput inputSourceMap) {
+    SourceMapConsumerV3 consumer = inputSourceMap.getSourceMap(errorManager);
+    if (consumer == null) {
+      return;
+    }
+    Collection<String> sourcesContent = consumer.getOriginalSourcesContent();
+    if (sourcesContent == null) {
+      return;
+    }
+    Iterator<String> content = sourcesContent.iterator();
+    Iterator<String> sources = consumer.getOriginalSources().iterator();
+    while (sources.hasNext() && content.hasNext()) {
+      sourceMap.addSourceFile(sources.next(), content.next());
+    }
+    if (sources.hasNext() || content.hasNext()) {
+      throw new RuntimeException(
+          "Source map's \"sources\" and \"sourcesContent\" lengths do not match.");
+    }
   }
 
   @Override
@@ -3442,7 +3476,11 @@ ModuleLoader getModuleLoader() {
   private void addFilesToSourceMap(Iterable<? extends SourceFile> files) {
     if (getOptions().sourceMapIncludeSourcesContent && getSourceMap() != null) {
       for (SourceFile file : files) {
-        getSourceMap().addSourceFile(file);
+        try {
+          getSourceMap().addSourceFile(file.getName(), file.getCode());
+        } catch (IOException e) {
+          throw new RuntimeException("Cannot read code of a source map's source file.", e);
+        }
       }
     }
   }

src/com/google/javascript/jscomp/SourceMap.java

@@ -29,8 +29,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 import javax.annotation.Nullable;
 
 /**
@@ -44,10 +42,6 @@
  * @author johnlenz@google.com (John Lenz)
  */
 public final class SourceMap {
-
-  private static final Logger logger =
-      Logger.getLogger("com.google.javascript.jscomp");
-
   /**
    * An enumeration of available source map formats
    */
@@ -202,12 +196,8 @@ public void addMapping(
         outputStartPosition, outputEndPosition);
   }
 
-  public void addSourceFile(SourceFile sourceFile) {
-    try {
-      generator.addSourcesContent(fixupSourceLocation(sourceFile.getName()), sourceFile.getCode());
-    } catch (IOException e) {
-      logger.log(Level.WARNING, "Exception while adding source content to source map.", e);
-    }
+  public void addSourceFile(String name, String code) {
+    generator.addSourcesContent(fixupSourceLocation(name), code);
   }
 
   /**

test/com/google/javascript/jscomp/CompilerTest.java

@@ -209,6 +209,37 @@ public void testInputSourceMapInline() throws Exception {
     SourceMapInput inputSourceMap = compiler.inputSourceMaps.get("tmp");
     SourceMapConsumerV3 sourceMap = inputSourceMap.getSourceMap(null);
     assertThat(sourceMap.getOriginalSources()).containsExactly("foo.ts");
+    assertNull(sourceMap.getOriginalSourcesContent());
+  }
+
+  private static final String SOURCE_MAP_TEST_CONTENT =
+      Joiner.on("\n")
+          .join(
+              "var A = (function () {",
+              "    function A(input) {",
+              "        this.a = input;",
+              "    }",
+              "    return A;",
+              "}());",
+              "console.log(new A(1));");
+
+  // Similar to BASE64_ENCODED_SOURCE_MAP; contains encoded SOURCE_MAP but with
+  // SOURCE_MAP_TEST_CONTENT as the only item of sourcesContent corresponding
+  // to "foo.ts" sources item.
+  private static final String BASE64_ENCODED_SOURCE_MAP_WITH_CONTENT =
+      "data:application/json;base64,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";
+
+  public void testInputSourceMapInlineContent() throws Exception {
+    Compiler compiler = new Compiler();
+    compiler.initCompilerOptionsIfTesting();
+    String code =
+        SOURCE_MAP_TEST_CODE + "\n//# sourceMappingURL=" + BASE64_ENCODED_SOURCE_MAP_WITH_CONTENT;
+    CompilerInput input = new CompilerInput(SourceFile.fromCode("tmp", code));
+    input.getAstRoot(compiler);
+    SourceMapInput inputSourceMap = compiler.inputSourceMaps.get("tmp");
+    SourceMapConsumerV3 sourceMap = inputSourceMap.getSourceMap(null);
+    assertThat(sourceMap.getOriginalSources()).containsExactly("foo.ts");
+    assertThat(sourceMap.getOriginalSourcesContent()).containsExactly(SOURCE_MAP_TEST_CONTENT);
   }
 
   public void testResolveRelativeSourceMap() throws Exception {
@@ -326,8 +357,31 @@ public void testApplyInputSourceMaps() throws Exception {
     assertThat(mapping.getLineNumber()).isEqualTo(18);
     assertThat(mapping.getColumnPosition()).isEqualTo(26);
     assertThat(mapping.getIdentifier()).isEqualTo("testSymbolName");
+    assertThat(consumer.getOriginalSources()).containsExactly("input.js", "input.ts");
+    assertNull(consumer.getOriginalSourcesContent());
   }
 
+  public void testKeepInputSourceMapsSourcesContent() throws Exception {
+    CompilerOptions options = new CompilerOptions();
+    options.setLanguageIn(LanguageMode.ECMASCRIPT3);
+    options.sourceMapOutputPath = "fake/source_map_path.js.map";
+    options.applyInputSourceMaps = true;
+    options.sourceMapIncludeSourcesContent = true;
+    String code = SOURCE_MAP_TEST_CODE + "\n//# sourceMappingURL="
+        + BASE64_ENCODED_SOURCE_MAP_WITH_CONTENT;
+    Compiler compiler = new Compiler();
+    SourceFile sourceFile = SourceFile.fromCode("input.js", code);
+    compiler.compile(EMPTY_EXTERNS.get(0), sourceFile, options);
+    assertThat(compiler.toSource()).isEqualTo(
+        "var X=function(){function X(input){this.y=input}return X}();console.log(new X(1));");
+    SourceMap sourceMap = compiler.getSourceMap();
+    StringWriter out = new StringWriter();
+    sourceMap.appendTo(out, "source.js.map");
+    SourceMapConsumerV3 consumer = new SourceMapConsumerV3();
+    consumer.parse(out.toString());
+    assertThat(consumer.getOriginalSources()).containsExactly("foo.ts");
+    assertThat(consumer.getOriginalSourcesContent()).containsExactly(SOURCE_MAP_TEST_CONTENT);
+  }
 
   private static final ImmutableList<SourceFile> EMPTY_EXTERNS =
       ImmutableList.of(SourceFile.fromCode("externs", ""));