src/java.base/share/classes/java/lang/AbstractStringBuilder.java

rev 54291 : 8221430: StringBuffer(CharSequence) constructor truncates when -XX:-CompactStrings specified
Reviewed-by: igerasim, rriggs
Contributed-by: Andrew Leonard <andrew_m_leonard@uk.ibm.com>

*** 90,112 ****
              coder = UTF16;
          }
      }
  
      /**
!      * Creates an AbstractStringBuilder with the specified coder and with
       * the initial capacity equal to the smaller of (length + addition)
       * and Integer.MAX_VALUE.
       */
!     AbstractStringBuilder(byte coder, int length, int addition) {
          if (length < 0) {
              throw new NegativeArraySizeException("Negative length: " + length);
          }
-         this.coder = coder;
          int capacity = (length < Integer.MAX_VALUE - addition)
                  ? length + addition : Integer.MAX_VALUE;
!         value = (coder == LATIN1)
!                 ? new byte[capacity] : StringUTF16.newBytesFor(capacity);
      }
  
      /**
       * Compares the objects of two AbstractStringBuilder implementations lexicographically.
       *
--- 90,117 ----
              coder = UTF16;
          }
      }
  
      /**
!      * Creates an AbstractStringBuilder with the specified coder
!      * (coderHint is used when compact strings are enabled) and with
       * the initial capacity equal to the smaller of (length + addition)
       * and Integer.MAX_VALUE.
       */
!     AbstractStringBuilder(byte coderHint, int length, int addition) {
          if (length < 0) {
              throw new NegativeArraySizeException("Negative length: " + length);
          }
          int capacity = (length < Integer.MAX_VALUE - addition)
                  ? length + addition : Integer.MAX_VALUE;
!         if (COMPACT_STRINGS && coderHint == LATIN1) {
!             value = new byte[capacity];
!             coder = LATIN1;
!         } else {
!             value = StringUTF16.newBytesFor(capacity);
!             coder = UTF16;
!         }
      }
  
      /**
       * Compares the objects of two AbstractStringBuilder implementations lexicographically.
       *
*** 1739,1744 ****
--- 1744,1763 ----
          if (start < 0 || start > end || end > len) {
              throw new StringIndexOutOfBoundsException(
                  "start " + start + ", end " + end + ", length " + len);
          }
      }
+ 
+     /**
+      * Determines the "coder" of the given CharSequence.
+      * If the coder cannot be determined, returns LATIN1.
+      */
+     static byte getCharSequenceCoderHint(CharSequence seq) {
+         if (seq instanceof String) {
+             return ((String)seq).coder();
+         } else if (seq instanceof AbstractStringBuilder) {
+             return ((AbstractStringBuilder)seq).getCoder();
+         } else {
+             return LATIN1;
+         }
+     }
  }