Jif Change Log
==============

This file documents changes between releases of Jif.

2008-04-15    Jif 3.2.0
    * Refactoring for cleaner support of extensions, including Jifclipse.
    * Minor bug fixes and style changes.
    * Allow reader policies o->_ and writer policies o<-_ to be
      dropped from labels. (Principal _ is the bottom principal, and
      thus o->_ and o<-_ do not restrict the the sets of readers and 
      writers.)
      
2007-11-01    Jif 3.1.1
    * Based on Polyglot 2.3.0
    * Checked endorse construct
       * A useful form of the endorse statement for the common
         case of validating an untrusted value. See the Jif 
         manual for more details.
    * Constant arrays
       * Arrays can be declared constant, meaning their
         contents will not change after initialization. This
         allows more permissive label checking. See the Jif 
         manual for more details.
    * Dataflow analysis for array bounds
       * Analysis is able to determine if some array access
         and new array expressions will not throw
         runtime exceptions.
    * Numerous bug fixes
    
2006-06-09    Jif 3.0.0
    * Added integrity
       * See the Jif manual for a full explanation.
       * Labels now form a complete lattice (meet operation
         supported).
    * Optional checking for robustness
       * See the Jif manual for a full explanation.
       * Label checking rules to enforce robustness against all
         attackers can be turned on using the "-robust" command line
         option.
    * Syntactical/lexical changes
       * UTF-8 encoded source files accepted
       * A reader policy "p:q" can also be written "p->q" or
         "p&#8594;q" (the arrow is Unicode character 8594)
       * A writer policy "p!:q" can also be written "p-<q" or
         "p&#8592;q" (the arrow is Unicode character 8592)
       * Downgrades now explicitly mention the from and to labels
            e.g., declassify(h, {Alice:} to {Alice:Bob})
    * Richer principals       
       * Top and bottom principals now explicitly represented.
       * Conjunctive and disjunctive principals now supported.
    * Runtime label and principal tests
       * A new binary operator "equiv" added. For principals, "p equiv
         q" is equivalent to "p actsfor q" and "q actsfor p". For
         labels, "L1 equiv L2" is equivalent to "L1 <= L2" and "L2 <=
         L1".
       * Principal and label comparisons can be used as arbitrary
         boolean expressions. e.g., "boolean b = (p actsfor q);" if a
         principal or label test occurs as a conjunct of an
         if-statement, then the label environment used to label check
         the consequent will include this fact.
    * Jif manual significantly expanded, including section on the
      label checking rules in Jif.
    * Jif library code now has HashMap and HashSet implementations.
    * Numerous bug fixes.

2006-03-13    Jif 2.0.1
    * Numerous bug fixes.
    * Label less-than-or-equal constraints for methods.
    * Map implementation in jif.util library.
    * Simple runtime class analysis removes the need to statically handle 
            some spurious ClassCastExceptions
    * jif.lang.IDComparable interface now with additional method
            equals(label lbl, IDComparable[lbl] o)
        
2005-08-26    Jif 2.0.0
    * Class parameters now represented at runtime.
    * Dynamic labels and principals more expressive: now allow access paths.
    * Allow user-defined principals.
    * Not-null checking more precise.
    * Better documentation.
    * Based on the Polyglot 2.0.0 architecture.

2004-10-04    Jif 1.1.1
    * Based on the Polyglot 1.3.0 architecture
    * Now includes required Polyglot jar files in the distribution
    
2004-04-13    Jif 1.1.0
    * Based on the Polyglot 1.2.0 architecture.
    * Improved error messages.
    * New command line option to the Jif compiler: "-explain" (or "-e") 
      makes the compiler provide more information about why label checking 
      failed.      
    * The signature for the "public static void main" method for Jif 
      programs can now optionally include a dynamic principal, who is the 
      current user. See the file examples/README in the distribution for 
      more information.
    * Misc bug fixes, including:
          * The label "this" cannot be used in a static context.
          * Incorrect labels missing colons (e.g., "{Alice}") are detected.
          * Parameterized classes cannot be subclasses of 
            "java.lang.Throwable".
          * Final local variables require an initializer.
          * Implementation of acts for corrected.

2003-07-11    Jif 1.0.0
    * Based on the Polyglot 1.0.0 architecture.
    * Bounded label parameters
    * Non-null analysis to remove spurious exceptions
    * New example program: Battleship 

2001-09-06    Jif 0.9.2
    * Fixed a bug with loading external principals.
    * Fixed a bug with label checking loop statements.
    * Fixed serialization bug with jltools.util.Enum.
    * Installation procedure simplified.
    * Fixed Jif runtime interface.

2001-08-08    Jif 0.9.0
    * Fixed many bugs with label/principal parameters and dynamic labels.
    * Improved error reporting.
    * Added Jif runtime, which provides the ability to read and write files.
    * Added a utility to convert local users to Jif external principals.

2001-06-08    Jif 0.8.0
    * Many bug fixes with porting Jif to JLTools 0.9.0.

2001-05-16    Jif 0.7.0 (JLTools 0.9.0)
    * JLTools completely rewritten.
