If not found in the field hierarchy, /Q and /DA are supposed to be
looked up in the document-level form dictionary. /DR is supposed to
only come from the document dictionary.
This results in a performance penalty of 1% to 2% when replaceObject
and swapObjects are never called and a somewhat larger penalty if they
are called, but it's worth it to avoid very confusing behavior as
discussed in depth in qpdf#507.
Also fix a bug in checking consistency of length for stream data
providers. Length should not be checked or recorded if the provider
says it failed to generate the data.
I thought /EFF was supposed to be used as a default for decrypting
embedded file streams, but actually it's supposed to be advice to a
conforming writer about handling new ones. This makes sense since the
findAttachmentStreams code, which is not actually needed, was never
right.
When removing unreferenced resources, notice if a page (recursively)
contains a form XObject with unreferenced resources, and count any
such resources as referenced by the page.
Keep a std::pair internal to the iterators so that operator* can
return a reference and operator-> can work, and each can work without
copying pairs of objects around.
Create a computationally and memory efficient implementation of name
and number trees that does binary searches as intended by the data
structure rather than loading into a map, which can use a great deal
of memory and can be very slow.
Avoid calling finish() multiple times on the pipeline passed to
pipeContentStreams. This commit also fixes a bug in which qpdf was not
exiting with the proper exit status if warnings found while splitting
pages; this was exposed by a test case that changed.
Make some more methods in QPDFPageObjectHelper work with form
XObjects, provide forEach methods to walk through nested form
XObjects, possibly recursively. This should make it easier to work
with form XObjects from user code.
Various PDF digital signing tools do not encrypt /Contents value in
signature dictionary. Adobe Acrobat Reader DC can handle a PDF with
the /Contents value not encrypted.
Write Contents in signature dictionary without encryption
Tests ensure that string /Contents are not handled specially when not
found in sig dicts.
Table 8.93 "Entries in a signature dictionary" in PDF 1.5 reference
describes that the value of Contents entry is a hexadecimal string
representation when ByteRange is specified.
This commit makes QPDF always uses hexadecimal strings representation
instead of literal strings for it.
This change works around STL problems with Embarcadero C++ Builder
version 10.2, but std::vector is more common than std::list in qpdf,
and this is a relatively new API, so an API change is tolerable.
Thanks to Thorsten Schöning <6223655+ams-tschoening@users.noreply.github.com>
for the fix.
This also reverts the addition of a new checkLinearization that
distinguishes errors from warnings. There's no practical distinction
between what was considered an error and what was considered a
warning.
Use PointerHolder in several places where manually memory allocation
and deallocation were being used. This helps to protect against memory
leaks when exceptions are thrown in surprising places.
In a small number of cases, it makes sense to replace an overloaded
function with a function that takes a default argument. We can do this
now because we've already broken binary compatibility since the last
release.
Have classes contain only a single private member of type
PointerHolder<Members>. This makes it safe to change the structure of
the Members class without breaking binary compatibility. Many of the
classes already follow this pattern quite successfully. This brings in
the rest of the class that are part of the public API.
This makes all integer type conversions that have potential data loss
explicit with calls that do range checks and raise an exception. After
this commit, qpdf builds with no warnings when -Wsign-conversion
-Wconversion is used with gcc or clang or when -W3 -Wd4800 is used
with MSVC. This significantly reduces the likelihood of potential
crashes from bogus integer values.
There are some parts of the code that take int when they should take
size_t or an offset. Such places would make qpdf not support files
with more than 2^31 of something that usually wouldn't be so large. In
the event that such a file shows up and is valid, at least qpdf would
raise an error in the right spot so the issue could be legitimately
addressed rather than failing in some weird way because of a silent
overflow condition.
Fix C++ exception handling when -fvisibility=hidden
Ensure that QPDFExc and QPDFSystemError are marked visible, so that their typeinfo will not be
suppressed when -fvisibility=hidden.
Details:
https://gcc.gnu.org/wiki/Visibility
We've actually seen a PDF file in the wild that contained EI
surrounded by delimiters inside the image data, which confused qpdf's
naive code. This significantly improves EI detection.
Add a version of expectInlineImage that takes an input source and
searches for EI. This is in preparation for improving the way EI is
found. This commit just refactors the code without changing the
functionality and adds tests to make sure the old and new code behave
identically.
When linearizing a file or getting the list of all pages in a file,
detect if the pages tree contains a duplicated page object and, if so,
shallow copy it. This makes it possible to have a one to one mapping
of page positions to page objects.
Setting encryption permissions for R >= 3 set permission bits in
groups corresponding to menu options in Acrobat 5. The new API allows
the bits to be set individually.
The original QPDF is only required now when the source
QPDFObjectHandle is a stream that gets its stream data from a
QPDFObjectHandle::StreamDataProvider.
Instead of calling assert for problems found during checking
linearization data, throw an exception which is later caught and
issued as an error. Ideally we would handle errors more robustly, but
this is still a significant improvement.
On certain operations, such as iterating through all objects and
adding new indirect objects, walk through the entire object structure
and explicitly resolve any indirect references to non-existent
objects. That prevents new objects from springing into existence and
causing the previously dangling references to point to them.
Instead of directly putting the contents of the annotation appearance
streams into the page's content stream, add commands to render the
form xobjects directly. This is a more robust way to do it than the
original solution as it works properly with patterns and avoids
problems with resource name clashes between the pages and the form
xobjects.
Flatten annotations by integrating their appearance streams into the
content stream of the containing page. In the case of form fields,
only flatten if /NeedAppearance is false (or equivalently absent). If
flattening form fields, also remove /AcroForm from the document
catalog.
Unparse is admittedly strange, but I'd rather be strange and
consistent, and everything else in the qpdf library uses unparse to
serialize. (If you're reading this, the convention of using "unparse"
comes from the "clu" programming language.)
It's not really a shallow copy. It just doesn't cross indirect object
boundaries. The old implementation had a bug that would cause multiple
shallow copies of the same object to share memory, which was not the
intention.
This is the beginning of higher-level API support using helper
classes. The goal is to be able to add more helpers without continuing
to pollute QPDF's and QPDFObjectHandle's public interfaces.
Remove calls to assertPageObject(). All cases in the library that
called assertPageObject() work fine if you don't call
assertPageObject() because nothing assumes anything that was being
checked by that call. Removing the calls enables more files to be
successfully processed.
The QPDF_String::getUTF8Val() method was not treating strings that
weren't explicitly Unicode as PDF Doc Encoded. This only affects
characters in the range 0x80 through 0xa0.
Implement a TokenFilter class and refactor Pl_QPDFTokenizer to use a
TokenFilter class called ContentNormalizer. Pl_QPDFTokenizer is now a
general filter that passes data through a TokenFilter.
Remove a redundant method that was equal to another one with
additional arguments. This breaks binary compatibility, but there are
other ABI breaking changes in the upcoming release, so now is the time
to do it.
Significant enhancements to the lexer to improve EOF handling and to
support comments and spaces as tokens. Various other minor issues were
fixed as well.
Add options to enable the raw encryption key to be directly shown or
specified. Thanks to Didier Stevens <didier.stevens@gmail.com> for the
idea and contribution of one implementation of this idea.
While scanning the file looking for objects, limit the length of
tokens we allow. This prevents us from getting caught up in reading a
file character by character while digging through large streams.
* Add support for PCLm using setPCLm() and writePCLm() methods in
QPDFWriter.hh and QPDFWriter.cc
* Add a function writePCLmHeader() for PCLm header in QPDFWriter
There is no need for a --precheck-streams option. We can do the
precheck without imposing any penalty, only re-encoding the stream if
it fails the first time.
This commit adds several API methods that enable control over which
types of filters QPDF will attempt to decode. It also adds support for
/RunLengthDecode and /DCTDecode filters for both encoding and
decoding.
When requested, QPDFWriter will do more aggress prechecking of streams
to make sure it can actually succeed in decoding them before
attempting to do so. This will allow preservation of raw data even
when the raw data is corrupted relative to the specified filters.
QPDFObjectHandle::parseInternal now issues warnings instead of
throwing exceptions for all error conditions that it finds (except
internal logic errors) and has stronger recovery for things like
invalid tokens and malformed dictionaries. This should improve qpdf's
ability to recover from a wide range of broken files that currently
cause it to fail.
During parsing of an object, sometimes parts of the object have to be
resolved. An example is stream lengths. If such an object directly or
indirectly points to the object being parsed, it can cause an infinite
loop. Guard against all cases of re-entrant resolution of objects.
For non-encrypted files, determinstic ID generation uses file contents
instead of timestamp and file name. At a small runtime cost, this
enables generation of the same /ID if the same inputs are converted in
the same way multiple times.
Pushing inherited objects to pages and getting all pages were both
prone to stack overflow infinite loops if there were loops in the
Pages dictionary. There is a general weakness in the code in that any
part of the code that traverses the Pages structure would be prone to
this and would have to implement its own loop detection. A more robust
fix may provide some general method for handling the Pages structure,
but it's probably not worth doing.
Note: addition of *Internal2 private functions was done rather than
changing signatures of existing methods to avoid breaking
compatibility.
Add new RandomDataProvider object and implement existing random number
generation in terms of that. This enables end users to supply their
own random data providers.
4.2.0 was binary incompatible in spite of there being no deletions or
changes to any public methods. As such, we have to bump the ABI and
are fixing some API breakage while we're at it.
Previous 4.3.0 target is now 5.1.0.
Rework QPDFWriter to always track old object IDs and QPDFObjGen
instead of int, thus not discarding the generation number. Switch to
QPDF::getCompressibleObjGen() to properly handle the case of an old
object eligible for compression that has a generation of other than
zero.
Explicitly state how QPDF handles empty passwords when writing files.
Apparently some libraries treat the empty string as the owner password
as an instruction to generate a random password.
Remove const qualifier from getTypeCode and get getTypeName methods of
QPDFObjectHandle, make them work properly for indirect objects, and
exercise them much better in the test suite.
Change object type Keyword to Operator, and place the order of the
object types in object_type_e in the same order as they are mentioned
in the PDF specification.
Note that this change only breaks backward compatibility with code
that has not yet been released.
Original code was written before we could shallow copy objects, so all
the filtering was done by suppressing the output of certain keys and
replacing them with other keys. Now we can simplify the code greatly
by modifying shallow copies of dictionaries in place.
Read and write support is implemented for /V=5 with /R=5 as well as
/R=6. /R=5 is the deprecated encryption method used by Acrobat IX.
/R=6 is the encryption method used by PDF 2.0 from ISO 32000-2.
Allowing users to subclass InputSource and Pipeline to read and write
from/to arbitrary sources provides the maximum flexibility for users
who want to read and write from other than files or memory.
Move object parsing code from QPDF to QPDFObjectHandle and
parameterize the parts of it that are specific to a QPDF object.
Provide a version that can't handle indirect objects and that can be
called on an arbitrary string.
A side effect of this change is that the offset used when reporting
invalid stream length has changed, but since the new value seems like
a better value than the old one, the test suite has been updated
rather than making the code backward compatible. This only effects
the offset reported for invalid streams that lack /Length or have an
invalid /Length key.
Updated some test code and exmaples to use QPDFObjectHandle::parse.
Supporting changes include adding a BufferInputSource constructor that
takes a string.
