Removing GUAVA XML escapers from junitrunner.

Bazel users that are using a different Guava version than the one in the
junitrunner jar are getting an IncompatibleClassChangeError. Rewriting
parts of junitrunner code so it won't depend on Guava anymore.

Continuing progress on issue #1150.

--
MOS_MIGRATED_REVID=132054901

3 files changed, 322 insertions, 1 deletions

diff --git a/src/java_tools/junitrunner/java/com/google/testing/junit/runner/model/XmlWriter.java b/src/java_tools/junitrunner/java/com/google/testing/junit/runner/model/XmlWriter.java
index 0910486d12..d60fea3e33 100644
--- a/src/java_tools/junitrunner/java/com/google/testing/junit/runner/model/XmlWriter.java
+++ b/src/java_tools/junitrunner/java/com/google/testing/junit/runner/model/XmlWriter.java
@@ -16,7 +16,7 @@ package com.google.testing.junit.runner.model;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 
-import com.google.common.xml.XmlEscapers;
+import com.google.testing.junit.runner.util.XmlEscapers;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
diff --git a/src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/CharEscaper.java b/src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/CharEscaper.java
new file mode 100644
index 0000000000..f7b1d86f5a
--- /dev/null
+++ b/src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/CharEscaper.java
@@ -0,0 +1,184 @@
+// Copyright 2016 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.testing.junit.runner.util;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * An escaper that uses an array to quickly look up replacement characters for a given {@code char}
+ * value. An additional safe range is provided that determines whether {@code char} values without
+ * specific replacements are to be considered safe and left unescaped or should be escaped in a
+ * general way.
+ */
+public abstract class CharEscaper {
+  // The replacement array.
+  private final char[][] replacements;
+  // The number of elements in the replacement array.
+  private final int replacementsLength;
+  // The first character in the safe range.
+  private final char safeMin;
+  // The last character in the safe range.
+  private final char safeMax;
+
+  // The multiplier for padding to use when growing the escape buffer.
+  private static final int DEST_PAD_MULTIPLIER = 2;
+
+  public CharEscaper(Map<Character, String> replacementMap, char safeMin, char safeMax) {
+    this.replacements = createReplacementArray(replacementMap);
+    this.replacementsLength = replacements.length;
+    this.safeMin = safeMin;
+    this.safeMax = safeMax;
+  }
+
+  public final String escape(String s) {
+    if (s == null) {
+      throw new NullPointerException();
+    }
+    for (int i = 0; i < s.length(); i++) {
+      char c = s.charAt(i);
+      if ((c < replacementsLength && replacements[c] != null) || c > safeMax || c < safeMin) {
+        return escapeSlow(s, i);
+      }
+    }
+    return s;
+  }
+
+  /**
+   * A thread-local destination buffer to keep us from creating new buffers. The starting size is
+   * 1024 characters.
+   */
+  private static final ThreadLocal<char[]> DEST_TL =
+      new ThreadLocal<char[]>() {
+        @Override
+        protected char[] initialValue() {
+          return new char[1024];
+        }
+      };
+
+  /**
+   * Returns the escaped form of a given literal string, starting at the given index. This method is
+   * called by the {@link #escape(String)} method when it discovers that escaping is required.
+   *
+   * @param s the literal string to be escaped
+   * @param index the index to start escaping from
+   * @return the escaped form of {@code string}
+   * @throws NullPointerException if {@code string} is null
+   */
+  final String escapeSlow(String s, int index) {
+    int slen = s.length();
+
+    // Get a destination buffer and setup some loop variables.
+    char[] dest = DEST_TL.get();
+    int destSize = dest.length;
+    int destIndex = 0;
+    int lastEscape = 0;
+
+    // Loop through the rest of the string, replacing when needed into the
+    // destination buffer, which gets grown as needed as well.
+    for (; index < slen; index++) {
+
+      // Get a replacement for the current character.
+      char[] r = escape(s.charAt(index));
+
+      // If no replacement is needed, just continue.
+      if (r == null) {
+        continue;
+      }
+
+      int rlen = r.length;
+      int charsSkipped = index - lastEscape;
+
+      // This is the size needed to add the replacement, not the full size
+      // needed by the string. We only regrow when we absolutely must, and
+      // when we do grow, grow enough to avoid excessive growing. Grow.
+      int sizeNeeded = destIndex + charsSkipped + rlen;
+      if (destSize < sizeNeeded) {
+        destSize = sizeNeeded + DEST_PAD_MULTIPLIER * (slen - index);
+        dest = growBuffer(dest, destIndex, destSize);
+      }
+
+      // If we have skipped any characters, we need to copy them now.
+      if (charsSkipped > 0) {
+        s.getChars(lastEscape, index, dest, destIndex);
+        destIndex += charsSkipped;
+      }
+
+      // Copy the replacement string into the dest buffer as needed.
+      if (rlen > 0) {
+        System.arraycopy(r, 0, dest, destIndex, rlen);
+        destIndex += rlen;
+      }
+      lastEscape = index + 1;
+    }
+
+    // Copy leftover characters if there are any.
+    int charsLeft = slen - lastEscape;
+    if (charsLeft > 0) {
+      int sizeNeeded = destIndex + charsLeft;
+      if (destSize < sizeNeeded) {
+
+        // Regrow and copy, expensive! No padding as this is the final copy.
+        dest = growBuffer(dest, destIndex, sizeNeeded);
+      }
+      s.getChars(lastEscape, slen, dest, destIndex);
+      destIndex = sizeNeeded;
+    }
+    return new String(dest, 0, destIndex);
+  }
+
+  final char[] escape(char c) {
+    if (c < replacementsLength) {
+      char[] chars = replacements[c];
+      if (chars != null) {
+        return chars;
+      }
+    }
+    if (c >= safeMin && c <= safeMax) {
+      return null;
+    }
+    return escapeUnsafe(c);
+  }
+
+  abstract char[] escapeUnsafe(char c);
+
+  /**
+   * Helper method to grow the character buffer as needed, this only happens once in a while so it's
+   * ok if it's in a method call. If the index passed in is 0 then no copying will be done.
+   */
+  private static char[] growBuffer(char[] dest, int index, int size) {
+    char[] copy = new char[size];
+    if (index > 0) {
+      System.arraycopy(dest, 0, copy, 0, index);
+    }
+    return copy;
+  }
+
+  private static char[][] createReplacementArray(Map<Character, String> map) {
+    if (map == null) {
+      throw new NullPointerException();
+    }
+    if (map.isEmpty()) {
+      return new char[0][0];
+    }
+    char max = Collections.max(map.keySet());
+    char[][] replacements = new char[max + 1][];
+    for (char c : map.keySet()) {
+      replacements[c] = map.get(c).toCharArray();
+    }
+    return replacements;
+  }
+}
+
diff --git a/src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/XmlEscapers.java b/src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/XmlEscapers.java
new file mode 100644
index 0000000000..7621a076bc
--- /dev/null
+++ b/src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/XmlEscapers.java
@@ -0,0 +1,137 @@
+// Copyright 2016 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.testing.junit.runner.util;
+
+import java.util.HashMap;
+import java.util.Map;
+import javax.annotation.Nullable;
+
+/**
+ * Utility class for dealing with escaping XML content and attributes.
+ */
+public class XmlEscapers {
+  private XmlEscapers() {}
+
+  private static final char MIN_ASCII_CONTROL_CHAR = 0x00;
+  private static final char MAX_ASCII_CONTROL_CHAR = 0x1F;
+
+  public static CharEscaper xmlContentEscaper() {
+    return XML_CONTENT_ESCAPER;
+  }
+
+  public static CharEscaper xmlAttributeEscaper() {
+    return XML_ATTRIBUTE_ESCAPER;
+  }
+
+  private static final CharEscaper XML_CONTENT_ESCAPER;
+  private static final CharEscaper XML_ATTRIBUTE_ESCAPER;
+
+  static {
+    Builder builder = Builder.builder();
+    builder.setSafeRange(Character.MIN_VALUE, '\uFFFD');
+    builder.setUnsafeReplacement("\uFFFD");
+
+    for (char c = MIN_ASCII_CONTROL_CHAR; c <= MAX_ASCII_CONTROL_CHAR; c++) {
+      if (c != '\t' && c != '\n' && c != '\r') {
+        builder.addEscape(c, "\uFFFD");
+      }
+    }
+
+    builder.addEscape('&', "&amp;");
+    builder.addEscape('<', "&lt;");
+    builder.addEscape('>', "&gt;");
+    XML_CONTENT_ESCAPER = builder.build();
+    builder.addEscape('\'', "&apos;");
+    builder.addEscape('"', "&quot;");
+    builder.addEscape('\t', "&#x9;");
+    builder.addEscape('\n', "&#xA;");
+    builder.addEscape('\r', "&#xD;");
+    XML_ATTRIBUTE_ESCAPER = builder.build();
+  }
+
+  /**
+   * A builder for CharEscaper.
+   */
+  static final class Builder {
+    private final Map<Character, String> replacementMap = new HashMap<>();
+    private char safeMin = Character.MIN_VALUE;
+    private char safeMax = Character.MAX_VALUE;
+    private String unsafeReplacement = null;
+
+    static Builder builder() {
+      return new Builder();
+    }
+    // The constructor is exposed via the builder() method above.
+    private Builder() {}
+
+    /**
+     * Sets the safe range of characters for the escaper. Characters in this range that have no
+     * explicit replacement are considered 'safe' and remain unescaped in the output. If
+     * {@code safeMax < safeMin} then the safe range is empty.
+     *
+     * @return the builder instance
+     */
+    Builder setSafeRange(char safeMin, char safeMax) {
+      this.safeMin = safeMin;
+      this.safeMax = safeMax;
+      return this;
+    }
+
+    /**
+     * Sets the replacement string for any characters outside the 'safe' range that have no explicit
+     * replacement. If {@code unsafeReplacement} is {@code null} then no replacement will occur, if
+     * it is {@code ""} then the unsafe characters are removed from the output.
+     *
+     * @return the builder instance
+     */
+    Builder setUnsafeReplacement(@Nullable String unsafeReplacement) {
+      this.unsafeReplacement = unsafeReplacement;
+      return this;
+    }
+
+    /**
+     * Adds a replacement string for the given input character. The specified character will be
+     * replaced by the given string whenever it occurs in the input, irrespective of whether it lies
+     * inside or outside the 'safe' range.
+     *
+     * @return the builder instance
+     * @throws NullPointerException if {@code replacement} is null
+     */
+    Builder addEscape(char c, String replacement) {
+      if (replacement == null) {
+        throw new NullPointerException();
+      }
+      // This can replace an existing character (the builder is re-usable).
+      replacementMap.put(c, replacement);
+      return this;
+    }
+
+    /**
+     * Returns a new CharEscaper based on the current state of the builder.
+     */
+    CharEscaper build() {
+      return new CharEscaper(replacementMap, safeMin, safeMax) {
+        private final char[] replacementChars =
+            unsafeReplacement != null ? unsafeReplacement.toCharArray() : null;
+
+        @Override
+        char[] escapeUnsafe(char c) {
+          return replacementChars;
+        }
+      };
+    }
+  }
+}
+