diff options
author | halcanary <halcanary@google.com> | 2015-10-09 13:09:58 -0700 |
---|---|---|
committer | Commit bot <commit-bot@chromium.org> | 2015-10-09 13:09:58 -0700 |
commit | 939c0fe51f157104758bcb268643c8b6d317a530 (patch) | |
tree | 1c2fb3639dd1ae608ae00fc99130d09a427bf5cd /src/pdf/SkPDFMetadata.cpp | |
parent | e361781bf7ce8acd4af00c426b34596804d45d77 (diff) |
SkPDF: Optionally output PDF/A-2b archive format.
Note: this format does not yet pass validation tests.
Add skia_pdf_generate_pdfa GYP flag. Default to off for now.
PDF/A files are not reproducable, so they make correctness
testing harder.
Turn the Metadata struct into te SkPDFMetadata struct. This
splits out a lot of functionality around both kinds of metadata.
When PDF/A is used, add an ID entry to the trailer.
Add SkPDFObjNumMap::addObjectRecursively.
Test with
GYP_DEFINES=skia_pdf_generate_pdfa=1 bin/sync-and-gyp
ninja -C out/Release dm
out/Release/dm --config pdf --src skp gm -w /tmp/dm
With skia_pdf_generate_pdfa=0, all PDFs generated from GMs and
SKPs are identical. With skia_pdf_generate_pdfa=1, all PDFs
generated from GMs and SKPs render identically in Pdfium.
BUG=skia:3110
Review URL: https://codereview.chromium.org/1394263003
Diffstat (limited to 'src/pdf/SkPDFMetadata.cpp')
-rw-r--r-- | src/pdf/SkPDFMetadata.cpp | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/src/pdf/SkPDFMetadata.cpp b/src/pdf/SkPDFMetadata.cpp new file mode 100644 index 0000000000..6a68a487b8 --- /dev/null +++ b/src/pdf/SkPDFMetadata.cpp @@ -0,0 +1,347 @@ +/* + * 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 "SkPDFMetadata.h" +#include "SkMD5.h" +#include "SkPDFTypes.h" + +SkPDFMetadata::UUID SkPDFMetadata::uuid() const { + // 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.write(uuidNamespace, strlen(uuidNamespace)); + SkMSec msec = SkTime::GetMSecs(); + md5.write(&msec, sizeof(msec)); + SkTime::DateTime dateTime; + SkTime::GetDateTime(&dateTime); + md5.write(&dateTime, sizeof(dateTime)); + if (fCreation) { + md5.write(fCreation.get(), sizeof(fCreation)); + } + if (fModified) { + md5.write(fModified.get(), sizeof(fModified)); + } + for (const auto& kv : fInfo) { + md5.write(kv.fKey.c_str(), kv.fKey.size()); + md5.write("\037", 1); + md5.write(kv.fValue.c_str(), kv.fValue.size()); + md5.write("\036", 1); + } + SkMD5::Digest digest; + md5.finish(digest); + // 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(UUID), "uuid_size"); + SkPDFMetadata::UUID uuid; + memcpy(&uuid, &digest, sizeof(digest)); + return uuid; +} + +SkPDFObject* SkPDFMetadata::CreatePdfId(const UUID& doc, const UUID& instance) { + // /ID [ <81b14aafa313db63dbd6f981e49f94f4> + // <81b14aafa313db63dbd6f981e49f94f4> ] + SkAutoTUnref<SkPDFArray> array(new SkPDFArray); + static_assert(sizeof(UUID) == 16, "uuid_size"); + array->appendString( + SkString(reinterpret_cast<const char*>(&doc), sizeof(UUID))); + array->appendString( + SkString(reinterpret_cast<const char*>(&instance), sizeof(UUID))); + return array.detach(); +} + +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); +} + +SkPDFObject* SkPDFMetadata::createDocumentInformationDict() const { + SkAutoTUnref<SkPDFDict> dict(new SkPDFDict); + static const char* keys[] = { + "Title", "Author", "Subject", "Keywords", "Creator"}; + for (const char* key : keys) { + for (const SkDocument::Attribute& keyValue : fInfo) { + if (keyValue.fKey.equals(key)) { + dict->insertString(key, keyValue.fValue); + } + } + } + dict->insertString("Producer", "Skia/PDF"); + if (fCreation) { + dict->insertString("CreationDate", pdf_date(*fCreation.get())); + } + if (fModified) { + dict->insertString("ModDate", pdf_date(*fModified.get())); + } + return dict.detach(); +} + +#ifdef SK_PDF_GENERATE_PDFA +// Improvement on SkStringPrintf to allow for arbitrarily long output. +// TODO: replace SkStringPrintf. +static SkString sk_string_printf(const char* format, ...) { +#ifdef SK_BUILD_FOR_WIN + va_list args; + va_start(args, format); + char buffer[1024]; + int length = _vsnprintf_s(buffer, sizeof(buffer), _TRUNCATE, format, args); + va_end(args); + if (length >= 0 && length < (int)sizeof(buffer)) { + return SkString(buffer, length); + } + va_start(args, format); + length = _vscprintf(format, args); + va_end(args); + + SkString string((size_t)length); + va_start(args, format); + SkDEBUGCODE(int check = ) _vsnprintf_s(string.writable_str(), length + 1, + _TRUNCATE, format, args); + va_end(args); + SkASSERT(check == length); + SkASSERT(string[length] == '\0'); + return skstd::move(string); +#else // C99/C++11 standard vsnprintf + // TODO: When all compilers support this, remove windows-specific code. + va_list args; + va_start(args, format); + char buffer[1024]; + int length = vsnprintf(buffer, sizeof(buffer), format, args); + va_end(args); + if (length < 0) { + return SkString(); + } + if (length < (int)sizeof(buffer)) { + return SkString(buffer, length); + } + SkString string((size_t)length); + va_start(args, format); + SkDEBUGCODE(int check = ) + vsnprintf(string.writable_str(), length + 1, format, args); + va_end(args); + SkASSERT(check == length); + SkASSERT(string[length] == '\0'); + return skstd::move(string); +#endif +} + +static const SkString get(const SkTArray<SkDocument::Attribute>& info, + const char* key) { + for (const auto& keyValue : info) { + if (keyValue.fKey.equals(key)) { + return keyValue.fValue; + } + } + return SkString(); +} + +#define HEXIFY(INPUT_PTR, OUTPUT_PTR, HEX_STRING, BYTE_COUNT) \ + do { \ + for (int i = 0; i < (BYTE_COUNT); ++i) { \ + uint8_t value = *(INPUT_PTR)++; \ + *(OUTPUT_PTR)++ = (HEX_STRING)[value >> 4]; \ + *(OUTPUT_PTR)++ = (HEX_STRING)[value & 0xF]; \ + } \ + } while (false) +static SkString uuid_to_string(const SkPDFMetadata::UUID& uuid) { + // 8-4-4-4-12 + char buffer[36]; // [32 + 4] + static const char gHex[] = "0123456789abcdef"; + SkASSERT(strlen(gHex) == 16); + char* ptr = buffer; + const uint8_t* data = uuid.fData; + HEXIFY(data, ptr, gHex, 4); + *ptr++ = '-'; + HEXIFY(data, ptr, gHex, 2); + *ptr++ = '-'; + HEXIFY(data, ptr, gHex, 2); + *ptr++ = '-'; + HEXIFY(data, ptr, gHex, 2); + *ptr++ = '-'; + HEXIFY(data, ptr, gHex, 6); + SkASSERT(ptr == buffer + 36); + SkASSERT(data == uuid.fData + 16); + return SkString(buffer, 36); +} +#undef HEXIFY + +namespace { +class PDFXMLObject : public SkPDFObject { +public: + PDFXMLObject(SkString xml) : fXML(skstd::move(xml)) {} + void emitObject(SkWStream* stream, + const SkPDFObjNumMap& omap, + const SkPDFSubstituteMap& smap) const override { + SkPDFDict dict("Metadata"); + dict.insertName("Subtype", "XML"); + dict.insertInt("Length", fXML.size()); + dict.emitObject(stream, omap, smap); + static const char streamBegin[] = " stream\n"; + stream->write(streamBegin, strlen(streamBegin)); + // Do not compress this. The standard requires that a + // program that does not understand PDF can grep for + // "<?xpacket" and extracť the entire XML. + stream->write(fXML.c_str(), fXML.size()); + static const char streamEnd[] = "\nendstream"; + stream->write(streamEnd, strlen(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; +} + +const 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.writable_str(); + 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] == '&') { + strncpy(out, kAmp, strlen(kAmp)); + out += strlen(kAmp); + } else if (input[i] == '<') { + strncpy(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.writable_str()[output.size()]); + *out = '\0'; + return skstd::move(output); +} + +SkPDFObject* SkPDFMetadata::createXMPObject(const UUID& doc, + const UUID& instance) const { + 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" // MetadataDate + "%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" + "<pdf:Producer>Skia/PDF</pdf:Producer>\n" + "%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; + SkString metadataDate; + if (fCreation) { + SkString tmp; + fCreation->toISO8601(&tmp); + SkASSERT(0 == count_xml_escape_size(tmp)); + // YYYY-mm-ddTHH:MM:SS[+|-]ZZ:ZZ; no need to escape + creationDate = sk_string_printf("<xmp:CreateDate>%s</xmp:CreateDate>\n", + tmp.c_str()); + } + if (fModified) { + SkString tmp; + fModified->toISO8601(&tmp); + SkASSERT(0 == count_xml_escape_size(tmp)); + modificationDate = sk_string_printf( + "<xmp:ModifyDate>%s</xmp:ModifyDate>\n", tmp.c_str()); + metadataDate = sk_string_printf( + "<xmp:MetadataDate>%s</xmp:MetadataDate>\n", tmp.c_str()); + } + + SkString title = + escape_xml(get(fInfo, "Title"), "<dc:title><rdf:Alt><rdf:li>", + "</rdf:li></rdf:Alt></dc:title>\n"); + SkString author = + escape_xml(get(fInfo, "Author"), "<dc:creator><rdf:Bag><rdf:li>", + "</rdf:li></rdf:Bag></dc:creator>\n"); + // TODO: in theory, XMP can support multiple authors. Split on a delimiter? + SkString subject = escape_xml(get(fInfo, "Subject"), + "<dc:description><rdf:Alt><rdf:li>", + "</rdf:li></rdf:Alt></dc:description>\n"); + SkString keywords1 = + escape_xml(get(fInfo, "Keywords"), "<dc:subject><rdf:Bag><rdf:li>", + "</rdf:li></rdf:Bag></dc:subject>\n"); + SkString keywords2 = escape_xml(get(fInfo, "Keywords"), "<pdf:Keywords>", + "</pdf:Keywords>\n"); + + // TODO: in theory, keywords can be a list too. + SkString creator = escape_xml(get(fInfo, "Creator"), "<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)); + return new PDFXMLObject(sk_string_printf( + templateString, modificationDate.c_str(), creationDate.c_str(), + metadataDate.c_str(), creator.c_str(), title.c_str(), + subject.c_str(), author.c_str(), keywords1.c_str(), + documentID.c_str(), instanceID.c_str(), keywords2.c_str())); +} + +#endif // SK_PDF_GENERATE_PDFA |