Enable parameter file support for excessively long commandlines.

--
PiperOrigin-RevId: 145473123
MOS_MIGRATED_REVID=145473123

1 files changed, 164 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/common/options/ParamsFilePreProcessor.java b/src/main/java/com/google/devtools/common/options/ParamsFilePreProcessor.java
new file mode 100644
index 0000000000..02fe877b2d
--- /dev/null
+++ b/src/main/java/com/google/devtools/common/options/ParamsFilePreProcessor.java
@@ -0,0 +1,164 @@
+// Copyright 2017 The Bazel Authors. 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.common.options;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystem;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+/**
+ * Defines an {@link ArgsPreProcessor} that will determine if the arguments list contains a "params"
+ * file that contains a list of options to be parsed.
+ *
+ * <p>Params files are used when the argument list of {@link Option} exceed the shells commandline
+ * length. A params file argument is defined as a path starting with @. It will also be the only
+ * entry in an argument list.
+ */
+public class ParamsFilePreProcessor implements ArgsPreProcessor {
+
+  static final String ERROR_MESSAGE_FORMAT = "Error reading params file: %s %s";
+
+  static final String TOO_MANY_ARGS_ERROR_MESSAGE_FORMAT =
+      "A params file must be the only argument: %s";
+
+  static final String UNFINISHED_QUOTE_MESSAGE_FORMAT = "Unfinished quote %s at %s";
+
+  private final FileSystem fs;
+
+  ParamsFilePreProcessor(FileSystem fs) {
+    this.fs = fs;
+  }
+
+  /**
+   * Parses the param file path and replaces the arguments list with the contents if one exists.
+   *
+   * @param args A list of arguments that may contain @&lt;path&gt; to a params file.
+   * @return A list of areguments suitable for parsing.
+   * @throws OptionsParsingException if the path does not exist.
+   */
+  @Override
+  public List<String> preProcess(List<String> args) throws OptionsParsingException {
+    if (!args.isEmpty() && args.get(0).startsWith("@")) {
+      if (args.size() > 1) {
+        throw new OptionsParsingException(
+            String.format(TOO_MANY_ARGS_ERROR_MESSAGE_FORMAT, args), args.get(0));
+      }
+      Path path = fs.getPath(args.get(0).substring(1));
+      try (Reader params = Files.newBufferedReader(path, StandardCharsets.UTF_8)) {
+        List<String> newArgs = new ArrayList<>();
+        StringBuilder arg = new StringBuilder();
+        CharIterator iterator = CharIterator.wrap(params);
+        while (iterator.hasNext()) {
+          char next = iterator.next();
+          if (Character.isWhitespace(next) && !iterator.isInQuote() && !iterator.isEscaped()) {
+            newArgs.add(arg.toString());
+            arg = new StringBuilder();
+          } else {
+            arg.append(next);
+          }
+        }
+        // If there is still an arg in the buffer, add it.
+        if (arg.length() > 0) {
+          newArgs.add(arg.toString());
+        }
+        // If we're still in a quote by the end of the file, throw an error.
+        if (iterator.isInQuote()) {
+          throw new OptionsParsingException(
+              String.format(ERROR_MESSAGE_FORMAT, path, iterator.getUnmatchedQuoteMessage()));
+        }
+        return newArgs;
+      } catch (RuntimeException | IOException e) {
+        throw new OptionsParsingException(
+            String.format(ERROR_MESSAGE_FORMAT, path, e.getMessage()), args.get(0), e);
+      }
+    }
+    return args;
+  }
+
+  // Doesn't implement iterator to avoid autoboxing and to throw exceptions.
+  static class CharIterator {
+
+    private final Reader reader;
+    private int readerPosition = 0;
+    private int singleQuoteStart = -1;
+    private int doubleQuoteStart = -1;
+    private boolean escaped = false;
+    private char lastChar = (char) -1;
+
+    public static CharIterator wrap(Reader reader) {
+      return new CharIterator(reader);
+    }
+
+    public CharIterator(Reader reader) {
+      this.reader = reader;
+    }
+
+    public boolean hasNext() throws IOException {
+      reader.mark(1);
+      int next = reader.read();
+      reader.reset();
+      return next != -1;
+    }
+
+    public boolean isInQuote() {
+      return singleQuoteStart != -1 || doubleQuoteStart != -1;
+    }
+
+    public boolean isEscaped() {
+      return escaped;
+    }
+
+    public String getUnmatchedQuoteMessage() {
+      StringBuilder message = new StringBuilder();
+      if (singleQuoteStart != -1) {
+        message.append(String.format(UNFINISHED_QUOTE_MESSAGE_FORMAT, "'", singleQuoteStart));
+      }
+      if (doubleQuoteStart != -1) {
+        message.append(String.format(UNFINISHED_QUOTE_MESSAGE_FORMAT, "\"", doubleQuoteStart));
+      }
+      return message.toString();
+    }
+
+    public char next() throws IOException {
+      if (!hasNext()) {
+        throw new NoSuchElementException();
+      }
+      char current = (char) reader.read();
+
+      // check to see if the current position is escaped
+      if (lastChar == '\\') {
+        escaped = true;
+      } else {
+        escaped = false;
+      }
+
+      if (!escaped && current == '\'') {
+        singleQuoteStart = singleQuoteStart == -1 ? readerPosition : -1;
+      }
+      if (!escaped && current == '"') {
+        doubleQuoteStart = doubleQuoteStart == -1 ? readerPosition : -1;
+      }
+
+      readerPosition++;
+      lastChar = current;
+      return current;
+    }
+  }
+}