After PR 4982, the rendering of the first two pages of http://www.openmagazin.cz/pdf/2011/openMagazin-2011-04.pdf (from issue 215) no longer completes.
The issue is that we cannot have `args === null` in `PartialEvaluator_buildPath`, but *must* use an empty array instead.
In this patch I've also moved the `argsLength` variable definition in `EvaluatorPreprocessor_read`, to make sure that it's always defined.
QueueOptimizer is really hard to read. Enough so that it's blocking my
efforts to streamline the representation used for operator lists.
This patch improves its readability in the following ways.
- More descriptive variable names make the sequence checking much clearer,
as do additional comments.
- The addState() functions now return the index of the first op past the
sequence, instead of setting context.currentOperation to the last op of
the sequence.
- The loop in optimize() is clearer.
- The array modification in the fourth addState() function is much clearer
-- we're just removing trios of ops.
- All four |addState| functions are now more consistent with each other.
I used some debug printfs to find documents where these optimizations are
used and then checked that the number of optimized ops was the same before
and after my changes.
This function can be called 100s of 1000s or even millions of times, and the
allocated return object accounts for 10% of all GC thing allocations for some
documents. It's easy to avoid, which reduces stress on the garbage collector,
and this patch does that.
PartialEvaluator.getTextContent() builds up textChunk strings 1 char at a time,
creating many 100s of 1000s of intermediate strings along the way. This patch
make it instead push chars to an array and then join them at the end, as we
have done in numerous other places.
The function `assertWllFormed` was doing nothing different than `assert` which is
available in the same namespace. Removing it will lighten the filesize - albeit
very slightly - and reduce complexity.
