address more comments

Author: carl-mastrangelo

core/src/main/java/io/grpc/InternalMetadata.java

@@ -61,6 +61,7 @@ public interface TrustedAsciiMarshaller<T> {
 
     /**
      * Parse a serialized metadata value from an ASCII string.
+     *
      * @param serialized value of metadata to parse
      * @return a parsed instance of type T
      */

core/src/main/java/io/grpc/Metadata.java

@@ -605,7 +605,7 @@ private AsciiKey(String name, AsciiMarshaller<T> marshaller) {
       super(name);
       Preconditions.checkArgument(
           !name.endsWith(BINARY_HEADER_SUFFIX),
-          "ASCII header is named %s. It must not end with %s",
+          "ASCII header is named %s.  Only binary headers may end with %s",
           name, BINARY_HEADER_SUFFIX);
       this.marshaller = Preconditions.checkNotNull(marshaller, "marshaller");
     }
@@ -631,7 +631,7 @@ private TrustedAsciiKey(String name, TrustedAsciiMarshaller<T> marshaller) {
       super(name);
       Preconditions.checkArgument(
           !name.endsWith(BINARY_HEADER_SUFFIX),
-          "ASCII header is named %s. It must not end with %s",
+          "ASCII header is named %s.  Only binary headers may end with %s",
           name, BINARY_HEADER_SUFFIX);
       this.marshaller = Preconditions.checkNotNull(marshaller, "marshaller");
     }

core/src/main/java/io/grpc/Status.java

@@ -592,13 +592,17 @@ public byte[] toAsciiString(String value) {
       for (int i = 0; i < valueBytes.length; i++) {
         byte b = valueBytes[i];
         // If there are only non escaping characters, skip the slow path.
-        if (b < ' ' || b >= '~' || b == '%') {
+        if (isEscapingChar(b)) {
           return toAsciiStringSlow(valueBytes, i);
         }
       }
       return valueBytes;
     }
 
+    private static boolean isEscapingChar(byte b) {
+      return b < ' ' || b >= '~' || b == '%';
+    }
+
     /**
      * @param valueBytes the UTF-8 bytes
      * @param ri The reader index, pointed at the first byte that needs escaping.
@@ -613,7 +617,7 @@ private static byte[] toAsciiStringSlow(byte[] valueBytes, int ri) {
       for (; ri < valueBytes.length; ri++) {
         byte b = valueBytes[ri];
         // Manually implement URL encoding, per the gRPC spec.
-        if (b < ' ' || b >= '~' || b == '%') {
+        if (isEscapingChar(b)) {
           escapedBytes[wi] = '%';
           escapedBytes[wi + 1] = HEX[(b >> 4) & 0xF];
           escapedBytes[wi + 2] = HEX[b & 0xF];