diff options
Diffstat (limited to 'gfx/skia/skia/src/pdf/SkPDFMetadata.cpp')
| -rw-r--r-- | gfx/skia/skia/src/pdf/SkPDFMetadata.cpp | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/pdf/SkPDFMetadata.cpp b/gfx/skia/skia/src/pdf/SkPDFMetadata.cpp new file mode 100644 index 0000000000..943dfbc846 --- /dev/null +++ b/gfx/skia/skia/src/pdf/SkPDFMetadata.cpp @@ -0,0 +1,325 @@ +/* + * Copyright 2015 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#include "src/pdf/SkPDFMetadata.h" + +#include "include/private/base/SkTo.h" +#include "src/base/SkUTF.h" +#include "src/base/SkUtils.h" +#include "src/core/SkMD5.h" +#include "src/pdf/SkPDFTypes.h" + +#include <utility> + +static constexpr SkTime::DateTime kZeroTime = {0, 0, 0, 0, 0, 0, 0, 0}; + +static bool operator!=(const SkTime::DateTime& u, const SkTime::DateTime& v) { + return u.fTimeZoneMinutes != v.fTimeZoneMinutes || + u.fYear != v.fYear || + u.fMonth != v.fMonth || + u.fDayOfWeek != v.fDayOfWeek || + u.fDay != v.fDay || + u.fHour != v.fHour || + u.fMinute != v.fMinute || + u.fSecond != v.fSecond; +} + +static SkString pdf_date(const SkTime::DateTime& dt) { + int timeZoneMinutes = SkToInt(dt.fTimeZoneMinutes); + char timezoneSign = timeZoneMinutes >= 0 ? '+' : '-'; + int timeZoneHours = SkTAbs(timeZoneMinutes) / 60; + timeZoneMinutes = SkTAbs(timeZoneMinutes) % 60; + return SkStringPrintf( + "D:%04u%02u%02u%02u%02u%02u%c%02d'%02d'", + static_cast<unsigned>(dt.fYear), static_cast<unsigned>(dt.fMonth), + static_cast<unsigned>(dt.fDay), static_cast<unsigned>(dt.fHour), + static_cast<unsigned>(dt.fMinute), + static_cast<unsigned>(dt.fSecond), timezoneSign, timeZoneHours, + timeZoneMinutes); +} + +namespace { +static const struct { + const char* const key; + SkString SkPDF::Metadata::*const valuePtr; +} gMetadataKeys[] = { + {"Title", &SkPDF::Metadata::fTitle}, + {"Author", &SkPDF::Metadata::fAuthor}, + {"Subject", &SkPDF::Metadata::fSubject}, + {"Keywords", &SkPDF::Metadata::fKeywords}, + {"Creator", &SkPDF::Metadata::fCreator}, + {"Producer", &SkPDF::Metadata::fProducer}, +}; +} // namespace + +std::unique_ptr<SkPDFObject> SkPDFMetadata::MakeDocumentInformationDict( + const SkPDF::Metadata& metadata) { + auto dict = SkPDFMakeDict(); + for (const auto keyValuePtr : gMetadataKeys) { + const SkString& value = metadata.*(keyValuePtr.valuePtr); + if (value.size() > 0) { + dict->insertTextString(keyValuePtr.key, value); + } + } + if (metadata.fCreation != kZeroTime) { + dict->insertTextString("CreationDate", pdf_date(metadata.fCreation)); + } + if (metadata.fModified != kZeroTime) { + dict->insertTextString("ModDate", pdf_date(metadata.fModified)); + } + return std::move(dict); +} + +SkUUID SkPDFMetadata::CreateUUID(const SkPDF::Metadata& metadata) { + // The main requirement is for the UUID to be unique; the exact + // format of the data that will be hashed is not important. + SkMD5 md5; + const char uuidNamespace[] = "org.skia.pdf\n"; + md5.writeText(uuidNamespace); + double msec = SkTime::GetMSecs(); + md5.write(&msec, sizeof(msec)); + SkTime::DateTime dateTime; + SkTime::GetDateTime(&dateTime); + md5.write(&dateTime, sizeof(dateTime)); + md5.write(&metadata.fCreation, sizeof(metadata.fCreation)); + md5.write(&metadata.fModified, sizeof(metadata.fModified)); + + for (const auto keyValuePtr : gMetadataKeys) { + md5.writeText(keyValuePtr.key); + md5.write("\037", 1); + const SkString& value = metadata.*(keyValuePtr.valuePtr); + md5.write(value.c_str(), value.size()); + md5.write("\036", 1); + } + SkMD5::Digest digest = md5.finish(); + // See RFC 4122, page 6-7. + digest.data[6] = (digest.data[6] & 0x0F) | 0x30; + digest.data[8] = (digest.data[6] & 0x3F) | 0x80; + static_assert(sizeof(digest) == sizeof(SkUUID), "uuid_size"); + SkUUID uuid; + memcpy((void*)&uuid, &digest, sizeof(digest)); + return uuid; +} + +std::unique_ptr<SkPDFObject> SkPDFMetadata::MakePdfId(const SkUUID& doc, const SkUUID& instance) { + // /ID [ <81b14aafa313db63dbd6f981e49f94f4> + // <81b14aafa313db63dbd6f981e49f94f4> ] + auto array = SkPDFMakeArray(); + static_assert(sizeof(SkUUID) == 16, "uuid_size"); + array->appendByteString(SkString(reinterpret_cast<const char*>(&doc ), sizeof(SkUUID))); + array->appendByteString(SkString(reinterpret_cast<const char*>(&instance), sizeof(SkUUID))); + return std::move(array); +} + +// Convert a block of memory to hexadecimal. Input and output pointers will be +// moved to end of the range. +static void hexify(const uint8_t** inputPtr, char** outputPtr, int count) { + SkASSERT(inputPtr && *inputPtr); + SkASSERT(outputPtr && *outputPtr); + while (count-- > 0) { + uint8_t value = *(*inputPtr)++; + *(*outputPtr)++ = SkHexadecimalDigits::gLower[value >> 4]; + *(*outputPtr)++ = SkHexadecimalDigits::gLower[value & 0xF]; + } +} + +static SkString uuid_to_string(const SkUUID& uuid) { + // 8-4-4-4-12 + char buffer[36]; // [32 + 4] + char* ptr = buffer; + const uint8_t* data = uuid.fData; + hexify(&data, &ptr, 4); + *ptr++ = '-'; + hexify(&data, &ptr, 2); + *ptr++ = '-'; + hexify(&data, &ptr, 2); + *ptr++ = '-'; + hexify(&data, &ptr, 2); + *ptr++ = '-'; + hexify(&data, &ptr, 6); + SkASSERT(ptr == buffer + 36); + SkASSERT(data == uuid.fData + 16); + return SkString(buffer, 36); +} + +namespace { +class PDFXMLObject final : public SkPDFObject { +public: + PDFXMLObject(SkString xml) : fXML(std::move(xml)) {} + void emitObject(SkWStream* stream) const override { + SkPDFDict dict("Metadata"); + dict.insertName("Subtype", "XML"); + dict.insertInt("Length", fXML.size()); + dict.emitObject(stream); + static const char streamBegin[] = " stream\n"; + stream->writeText(streamBegin); + // Do not compress this. The standard requires that a + // program that does not understand PDF can grep for + // "<?xpacket" and extract the entire XML. + stream->write(fXML.c_str(), fXML.size()); + static const char streamEnd[] = "\nendstream"; + stream->writeText(streamEnd); + } + +private: + const SkString fXML; +}; +} // namespace + +static int count_xml_escape_size(const SkString& input) { + int extra = 0; + for (size_t i = 0; i < input.size(); ++i) { + if (input[i] == '&') { + extra += 4; // strlen("&") - strlen("&") + } else if (input[i] == '<') { + extra += 3; // strlen("<") - strlen("<") + } + } + return extra; +} + +SkString escape_xml(const SkString& input, + const char* before = nullptr, + const char* after = nullptr) { + if (input.size() == 0) { + return input; + } + // "&" --> "&" and "<" --> "<" + // text is assumed to be in UTF-8 + // all strings are xml content, not attribute values. + size_t beforeLen = before ? strlen(before) : 0; + size_t afterLen = after ? strlen(after) : 0; + int extra = count_xml_escape_size(input); + SkString output(input.size() + extra + beforeLen + afterLen); + char* out = output.data(); + if (before) { + strncpy(out, before, beforeLen); + out += beforeLen; + } + static const char kAmp[] = "&"; + static const char kLt[] = "<"; + for (size_t i = 0; i < input.size(); ++i) { + if (input[i] == '&') { + memcpy(out, kAmp, strlen(kAmp)); + out += strlen(kAmp); + } else if (input[i] == '<') { + memcpy(out, kLt, strlen(kLt)); + out += strlen(kLt); + } else { + *out++ = input[i]; + } + } + if (after) { + strncpy(out, after, afterLen); + out += afterLen; + } + // Validate that we haven't written outside of our string. + SkASSERT(out == &output.data()[output.size()]); + *out = '\0'; + return output; +} + +SkPDFIndirectReference SkPDFMetadata::MakeXMPObject( + const SkPDF::Metadata& metadata, + const SkUUID& doc, + const SkUUID& instance, + SkPDFDocument* docPtr) { + static const char templateString[] = + "<?xpacket begin=\"\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>\n" + "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\"\n" + " x:xmptk=\"Adobe XMP Core 5.4-c005 78.147326, " + "2012/08/23-13:03:03\">\n" + "<rdf:RDF " + "xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n" + "<rdf:Description rdf:about=\"\"\n" + " xmlns:xmp=\"http://ns.adobe.com/xap/1.0/\"\n" + " xmlns:dc=\"http://purl.org/dc/elements/1.1/\"\n" + " xmlns:xmpMM=\"http://ns.adobe.com/xap/1.0/mm/\"\n" + " xmlns:pdf=\"http://ns.adobe.com/pdf/1.3/\"\n" + " xmlns:pdfaid=\"http://www.aiim.org/pdfa/ns/id/\">\n" + "<pdfaid:part>2</pdfaid:part>\n" + "<pdfaid:conformance>B</pdfaid:conformance>\n" + "%s" // ModifyDate + "%s" // CreateDate + "%s" // xmp:CreatorTool + "<dc:format>application/pdf</dc:format>\n" + "%s" // dc:title + "%s" // dc:description + "%s" // author + "%s" // keywords + "<xmpMM:DocumentID>uuid:%s</xmpMM:DocumentID>\n" + "<xmpMM:InstanceID>uuid:%s</xmpMM:InstanceID>\n" + "%s" // pdf:Producer + "%s" // pdf:Keywords + "</rdf:Description>\n" + "</rdf:RDF>\n" + "</x:xmpmeta>\n" // Note: the standard suggests 4k of padding. + "<?xpacket end=\"w\"?>\n"; + + SkString creationDate; + SkString modificationDate; + if (metadata.fCreation != kZeroTime) { + SkString tmp; + metadata.fCreation.toISO8601(&tmp); + SkASSERT(0 == count_xml_escape_size(tmp)); + // YYYY-mm-ddTHH:MM:SS[+|-]ZZ:ZZ; no need to escape + creationDate = SkStringPrintf("<xmp:CreateDate>%s</xmp:CreateDate>\n", + tmp.c_str()); + } + if (metadata.fModified != kZeroTime) { + SkString tmp; + metadata.fModified.toISO8601(&tmp); + SkASSERT(0 == count_xml_escape_size(tmp)); + modificationDate = SkStringPrintf( + "<xmp:ModifyDate>%s</xmp:ModifyDate>\n", tmp.c_str()); + } + SkString title = + escape_xml(metadata.fTitle, + "<dc:title><rdf:Alt><rdf:li xml:lang=\"x-default\">", + "</rdf:li></rdf:Alt></dc:title>\n"); + SkString author = + escape_xml(metadata.fAuthor, "<dc:creator><rdf:Seq><rdf:li>", + "</rdf:li></rdf:Seq></dc:creator>\n"); + // TODO: in theory, XMP can support multiple authors. Split on a delimiter? + SkString subject = escape_xml( + metadata.fSubject, + "<dc:description><rdf:Alt><rdf:li xml:lang=\"x-default\">", + "</rdf:li></rdf:Alt></dc:description>\n"); + SkString keywords1 = + escape_xml(metadata.fKeywords, "<dc:subject><rdf:Bag><rdf:li>", + "</rdf:li></rdf:Bag></dc:subject>\n"); + SkString keywords2 = escape_xml(metadata.fKeywords, "<pdf:Keywords>", + "</pdf:Keywords>\n"); + // TODO: in theory, keywords can be a list too. + + SkString producer = escape_xml(metadata.fProducer, "<pdf:Producer>", "</pdf:Producer>\n"); + + SkString creator = escape_xml(metadata.fCreator, "<xmp:CreatorTool>", + "</xmp:CreatorTool>\n"); + SkString documentID = uuid_to_string(doc); // no need to escape + SkASSERT(0 == count_xml_escape_size(documentID)); + SkString instanceID = uuid_to_string(instance); + SkASSERT(0 == count_xml_escape_size(instanceID)); + + + auto value = SkStringPrintf( + templateString, modificationDate.c_str(), creationDate.c_str(), + creator.c_str(), title.c_str(), subject.c_str(), author.c_str(), + keywords1.c_str(), documentID.c_str(), instanceID.c_str(), + producer.c_str(), keywords2.c_str()); + + std::unique_ptr<SkPDFDict> dict = SkPDFMakeDict("Metadata"); + dict->insertName("Subtype", "XML"); + return SkPDFStreamOut(std::move(dict), + SkMemoryStream::MakeCopy(value.c_str(), value.size()), + docPtr, SkPDFSteamCompressionEnabled::No); +} + +#undef SKPDF_CUSTOM_PRODUCER_KEY +#undef SKPDF_PRODUCER +#undef SKPDF_STRING +#undef SKPDF_STRING_IMPL |