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Code Issues Releases Wiki Activity
56f1b411fe
qpdf/libqpdf/QPDF_json.cc
Jay Berkenbilt 7e7a9c4379 Parse objects; stream data is not yet handled
2022-05-20 09:16:25 -04:00

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#include <qpdf/QPDF.hh>
#include <qpdf/FileInputSource.hh>
#include <qpdf/QIntC.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>
#include <regex>
// This chart shows an example of the state transitions that would
// occur in parsing a minimal file.
// | st_initial
// { | -> st_top
// "qpdf": { | -> st_qpdf
// "objects": { | -> st_objects
// "obj:1 0 R": { | -> st_object_top
// "value": { | -> st_object
// "/Pages": "2 0 R", | ...
// "/Type": "/Catalog" | ...
// } | <- st_object_top
// }, | <- st_objects
// "obj:2 0 R": { | -> st_object_top
// "value": 12 | -> st_object
// } | <- st_object_top
// }, | <- st_objects
// "obj:4 0 R": { | -> st_object_top
// "stream": { | -> st_stream
// "data": "cG90YXRv", | ...
// "dict": { | -> st_object
// "/K": true | ...
// } | <- st_stream
// } | <- st_object_top
// }, | <- st_objects
// "trailer": { | -> st_trailer
// "value": { | -> st_object
// "/Root": "1 0 R", | ...
// "/Size": 7 | ...
// } | <- st_trailer
// } | <- st_objects
// } | <- st_qpdf
// } | <- st_top
// } | <- st_initial
static char const* JSON_PDF = (
// force line break
"%PDF-1.3\n"
"xref\n"
"0 1\n"
"0000000000 65535 f \n"
"trailer << /Size 1 >>\n"
"startxref\n"
"9\n"
"%%EOF\n");
static std::regex PDF_VERSION_RE("^\\d+\\.\\d+$");
static std::regex OBJ_KEY_RE("^obj:(\\d+) (\\d+) R$");
static std::regex INDIRECT_OBJ_RE("^(\\d+) (\\d+) R$");
static std::regex UNICODE_RE("^u:(.*)$");
static std::regex BINARY_RE("^b:((?:[0-9a-fA-F]{2})*)$");
static std::regex NAME_RE("^/.*$");
QPDF::JSONReactor::JSONReactor(
QPDF& pdf, std::string const& filename, bool must_be_complete) :
pdf(pdf),
filename(filename),
must_be_complete(must_be_complete),
errors(false),
parse_error(false),
saw_qpdf(false),
saw_objects(false),
saw_json_version(false),
saw_pdf_version(false),
saw_trailer(false),
state(st_initial),
next_state(st_top),
saw_value(false),
saw_stream(false),
saw_dict(false),
saw_data(false),
saw_datafile(false)
{
state_stack.push_back(st_initial);
}
void
QPDF::JSONReactor::error(size_t offset, std::string const& msg)
{
this->errors = true;
this->pdf.warn(
qpdf_e_json, this->cur_object, QIntC::to_offset(offset), msg);
}
bool
QPDF::JSONReactor::anyErrors() const
{
return this->errors;
}
void
QPDF::JSONReactor::containerStart()
{
state_stack.push_back(state);
state = next_state;
}
void
QPDF::JSONReactor::dictionaryStart()
{
containerStart();
}
void
QPDF::JSONReactor::arrayStart()
{
containerStart();
if (state == st_top) {
QTC::TC("qpdf", "QPDF_json top-level array");
throw std::runtime_error("QPDF JSON must be a dictionary");
}
}
void
QPDF::JSONReactor::containerEnd(JSON const& value)
{
state = state_stack.back();
state_stack.pop_back();
if (state == st_initial) {
if (!this->saw_qpdf) {
QTC::TC("qpdf", "QPDF_json missing qpdf");
error(0, "\"qpdf\" object was not seen");
} else {
if (!this->saw_json_version) {
QTC::TC("qpdf", "QPDF_json missing json version");
error(0, "\"qpdf.jsonversion\" was not seen");
}
if (must_be_complete && !this->saw_pdf_version) {
QTC::TC("qpdf", "QPDF_json missing pdf version");
error(0, "\"qpdf.pdfversion\" was not seen");
}
if (!this->saw_objects) {
QTC::TC("qpdf", "QPDF_json missing objects");
error(0, "\"qpdf.objects\" was not seen");
} else {
if (must_be_complete && !this->saw_trailer) {
QTC::TC("qpdf", "QPDF_json missing trailer");
error(0, "\"qpdf.objects.trailer\" was not seen");
}
}
}
} else if (state == st_objects) {
if (parse_error) {
// ignore
} else if (cur_object == "trailer") {
if (!saw_value) {
QTC::TC("qpdf", "QPDF_json trailer no value");
error(value.getStart(), "\"trailer\" is missing \"value\"");
}
} else if (saw_value == saw_stream) {
QTC::TC("qpdf", "QPDF_json value stream both or neither");
error(
value.getStart(),
"object must have exactly one of \"value\" or \"stream\"");
}
object_stack.clear();
this->cur_object = "";
this->saw_dict = false;
this->saw_data = false;
this->saw_datafile = false;
this->saw_value = false;
this->saw_stream = false;
} else if (state == st_object_top) {
if (saw_stream) {
if (!saw_dict) {
QTC::TC("qpdf", "QPDF_json stream no dict");
error(value.getStart(), "\"stream\" is missing \"dict\"");
}
if (must_be_complete) {
if (saw_data == saw_datafile) {
QTC::TC("qpdf", "QPDF_json data datafile both or neither");
error(
value.getStart(),
"\"stream\" must have exactly one of \"data\" or "
"\"datafile\"");
}
} else if (saw_data && saw_datafile) {
// QXXXQ
/// QTC::TC("qpdf", "QPDF_json data and datafile");
error(
value.getStart(),
"\"stream\" may at most one of \"data\" or \"datafile\"");
}
}
} else if ((state == st_stream) || (state == st_object)) {
if (!parse_error) {
object_stack.pop_back();
}
} else if (state == st_qpdf) {
for (auto const& og: this->reserved) {
// QXXXQ
// QTC::TC("qpdf", "QPDF_json non-trivial null reserved");
this->pdf.replaceObject(og, QPDFObjectHandle::newNull());
}
this->reserved.clear();
}
}
QPDFObjectHandle
QPDF::JSONReactor::reserveObject(std::string const& obj, std::string const& gen)
{
int o = QUtil::string_to_int(obj.c_str());
int g = QUtil::string_to_int(gen.c_str());
auto oh = pdf.reserveObjectIfNotExists(o, g);
if (oh.isReserved()) {
this->reserved.insert(QPDFObjGen(o, g));
}
return oh;
}
void
QPDF::JSONReactor::replaceObject(
QPDFObjectHandle to_replace, QPDFObjectHandle replacement)
{
auto og = to_replace.getObjGen();
this->reserved.erase(og);
this->pdf.replaceObject(og, replacement);
}
void
QPDF::JSONReactor::topLevelScalar()
{
QTC::TC("qpdf", "QPDF_json top-level scalar");
throw std::runtime_error("QPDF JSON must be a dictionary");
}
void
QPDF::JSONReactor::nestedState(
std::string const& key, JSON const& value, state_e next)
{
// Use this method when the next state is for processing a nested
// dictionary.
if (value.isDictionary()) {
this->next_state = next;
} else {
error(value.getStart(), "\"" + key + "\" must be a dictionary");
this->next_state = st_ignore;
this->parse_error = true;
}
}
bool
QPDF::JSONReactor::dictionaryItem(std::string const& key, JSON const& value)
{
if (state == st_ignore) {
QTC::TC("qpdf", "QPDF_json ignoring in st_ignore");
// ignore
} else if (state == st_top) {
if (key == "qpdf") {
this->saw_qpdf = true;
nestedState(key, value, st_qpdf);
} else {
// Ignore all other fields for forward compatibility.
// Don't use nestedState since this can be any type.
// QXXXQ QTC
next_state = st_ignore;
}
} else if (state == st_qpdf) {
if (key == "jsonversion") {
this->saw_json_version = true;
std::string v;
if (!(value.getNumber(v) && (v == "2"))) {
QTC::TC("qpdf", "QPDF_json bad json version");
error(value.getStart(), "only JSON version 2 is supported");
}
} else if (key == "pdfversion") {
this->saw_pdf_version = true;
bool version_okay = false;
std::string v;
if (value.getString(v)) {
std::smatch m;
if (std::regex_match(v, m, PDF_VERSION_RE)) {
version_okay = true;
this->pdf.m->pdf_version = v;
}
}
if (!version_okay) {
QTC::TC("qpdf", "QPDF_json bad pdf version");
error(value.getStart(), "invalid PDF version (must be x.y)");
}
} else if (key == "objects") {
this->saw_objects = true;
nestedState(key, value, st_objects);
} else {
// ignore unknown keys for forward compatibility
// QXXXQ QTC
next_state = st_ignore;
}
} else if (state == st_objects) {
std::smatch m;
if (key == "trailer") {
this->saw_trailer = true;
nestedState(key, value, st_trailer);
this->cur_object = "trailer";
} else if (std::regex_match(key, m, OBJ_KEY_RE)) {
// QXXXQ remember to handle null for delete
object_stack.push_back(reserveObject(m[1].str(), m[2].str()));
nestedState(key, value, st_object_top);
this->cur_object = key;
} else {
QTC::TC("qpdf", "QPDF_json bad object key");
error(
value.getStart(),
"object key should be \"trailer\" or \"obj:n n R\"");
next_state = st_ignore;
parse_error = true;
}
} else if (state == st_object_top) {
if (object_stack.size() == 0) {
throw std::logic_error("no object on stack in st_object_top");
}
auto tos = object_stack.back();
QPDFObjectHandle replacement;
if (key == "value") {
// Don't use nestedState since this can have any type.
this->saw_value = true;
next_state = st_object;
replacement = makeObject(value);
replaceObject(tos, replacement);
} else if (key == "stream") {
this->saw_stream = true;
nestedState(key, value, st_stream);
if (tos.isStream()) {
// QXXXQ reusing -- need QTC
} else {
replacement =
pdf.reserveStream(tos.getObjectID(), tos.getGeneration());
replaceObject(tos, replacement);
replacement.replaceStreamData(
"", "<<>>"_qpdf, "<<>>"_qpdf); // QXXXQ
}
} else {
// Ignore unknown keys for forward compatibility
// QXXXQ QTC
next_state = st_ignore;
}
if (replacement.isInitialized()) {
object_stack.pop_back();
object_stack.push_back(replacement);
}
} else if (state == st_trailer) {
if (key == "value") {
this->saw_value = true;
// The trailer must be a dictionary, so we can use nestedState.
nestedState("trailer.value", value, st_object);
this->pdf.m->trailer = makeObject(value);
} else if (key == "stream") {
// Don't need to set saw_stream here since there's already
// an error.
QTC::TC("qpdf", "QPDF_json trailer stream");
error(value.getStart(), "the trailer may not be a stream");
next_state = st_ignore;
parse_error = true;
} else {
// Ignore unknown keys for forward compatibility
// QXXXQ QTC
next_state = st_ignore;
}
} else if (state == st_stream) {
if (object_stack.size() == 0) {
throw std::logic_error("no object on stack in st_stream");
}
auto tos = object_stack.back();
if (!tos.isStream()) {
// QXXXQ QTC in update mode
error(value.getStart(), "this object is not a stream");
parse_error = true;
} else if (key == "dict") {
this->saw_dict = true;
// Since a stream dictionary must be a dictionary, we can
// use nestedState to transition to st_value.
nestedState("stream.dict", value, st_object);
auto dict = makeObject(value);
if (dict.isDictionary()) {
tos.replaceDict(dict);
} else {
// An error had already been given by nestedState
QTC::TC("qpdf", "QPDF_json stream dict not dict");
parse_error = true;
}
} else if (key == "data") {
this->saw_data = true;
// QXXXQ
} else if (key == "datafile") {
this->saw_datafile = true;
// QXXXQ
} else {
// Ignore unknown keys for forward compatibility.
// QXXXQ QTC
next_state = st_ignore;
}
} else if (state == st_object) {
if (!parse_error) {
auto dict = object_stack.back();
if (dict.isStream()) {
dict = dict.getDict();
}
dict.replaceKey(key, makeObject(value));
}
} else {
throw std::logic_error(
"QPDF_json: unknown state " + QUtil::int_to_string(state));
}
return true;
}
bool
QPDF::JSONReactor::arrayItem(JSON const& value)
{
if (state == st_object) {
if (!parse_error) {
auto tos = object_stack.back();
tos.appendItem(makeObject(value));
}
}
return true;
}
QPDFObjectHandle
QPDF::JSONReactor::makeObject(JSON const& value)
{
QPDFObjectHandle result;
std::string str_v;
bool bool_v = false;
std::smatch m;
if (value.isDictionary()) {
result = QPDFObjectHandle::newDictionary();
object_stack.push_back(result);
} else if (value.isArray()) {
result = QPDFObjectHandle::newArray();
object_stack.push_back(result);
} else if (value.isNull()) {
result = QPDFObjectHandle::newNull();
} else if (value.getBool(bool_v)) {
result = QPDFObjectHandle::newBool(bool_v);
} else if (value.getNumber(str_v)) {
if (QUtil::is_long_long(str_v.c_str())) {
result = QPDFObjectHandle::newInteger(
QUtil::string_to_ll(str_v.c_str()));
} else {
result = QPDFObjectHandle::newReal(str_v);
}
} else if (value.getString(str_v)) {
if (std::regex_match(str_v, m, INDIRECT_OBJ_RE)) {
result = reserveObject(m[1].str(), m[2].str());
} else if (std::regex_match(str_v, m, UNICODE_RE)) {
result = QPDFObjectHandle::newUnicodeString(m[1].str());
} else if (std::regex_match(str_v, m, BINARY_RE)) {
result = QPDFObjectHandle::newString(QUtil::hex_decode(m[1].str()));
} else if (std::regex_match(str_v, m, NAME_RE)) {
result = QPDFObjectHandle::newName(str_v);
} else {
QTC::TC("qpdf", "QPDF_json unrecognized string value");
error(value.getStart(), "unrecognized string value");
result = QPDFObjectHandle::newNull();
}
}
if (!result.isInitialized()) {
throw std::logic_error(
"JSONReactor::makeObject didn't initialize the object");
}
// QXXXQ include object number in description
result.setObjectDescription(
&this->pdf,
this->filename + " offset " + QUtil::uint_to_string(value.getStart()));
return result;
}
void
QPDF::createFromJSON(std::string const& json_file)
{
createFromJSON(std::make_shared<FileInputSource>(json_file.c_str()));
}
void
QPDF::createFromJSON(std::shared_ptr<InputSource> is)
{
processMemoryFile(is->getName().c_str(), JSON_PDF, strlen(JSON_PDF));
importJSON(is, true);
}
void
QPDF::updateFromJSON(std::string const& json_file)
{
updateFromJSON(std::make_shared<FileInputSource>(json_file.c_str()));
}
void
QPDF::updateFromJSON(std::shared_ptr<InputSource> is)
{
importJSON(is, false);
}
void
QPDF::importJSON(std::shared_ptr<InputSource> is, bool must_be_complete)
{
JSONReactor reactor(*this, is->getName(), must_be_complete);
try {
JSON::parse(*is, &reactor);
} catch (std::runtime_error& e) {
throw std::runtime_error(is->getName() + ": " + e.what());
}
if (reactor.anyErrors()) {
throw std::runtime_error(is->getName() + ": errors found in JSON");
}
// QXXXQ
// std::cout << "trailer:\n" << getTrailer().unparse() << std::endl;
// for (auto& oh: getAllObjects()) {
// std::cout << oh.unparse() << ":" << std::endl;
// std::cout << oh.unparseResolved() << std::endl;
// }
}
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