#include "xmpmeta/xmp_parser.h" #include <algorithm> #include <cstring> #include <sstream> #include <stack> #include "android-base/logging.h" #include "strings/case.h" #include "strings/numbers.h" #include "xmpmeta/base64.h" #include "xmpmeta/jpeg_io.h" #include "xmpmeta/xml/const.h" #include "xmpmeta/xml/deserializer_impl.h" #include "xmpmeta/xml/search.h" #include "xmpmeta/xml/utils.h" #include "xmpmeta/xmp_const.h" using ::dynamic_depth::xmpmeta::xml::DepthFirstSearch; using ::dynamic_depth::xmpmeta::xml::DeserializerImpl; using ::dynamic_depth::xmpmeta::xml::FromXmlChar; using ::dynamic_depth::xmpmeta::xml::GetFirstDescriptionElement; namespace dynamic_depth { namespace xmpmeta { namespace { const char kJpgExtension[] = "jpg"; const char kJpegExtension[] = "jpeg"; bool BoolStringToBool(const string& bool_str, bool* value) { if (dynamic_depth::StringCaseEqual(bool_str, "true")) { *value = true; return true; } if (dynamic_depth::StringCaseEqual(bool_str, "false")) { *value = false; return true; } return false; } // Converts string_property to the type T. template <typename T> bool ConvertStringPropertyToType(const string& string_property, T* value); // Gets the end of the XMP meta content. If there is no packet wrapper, returns // data.length, otherwise returns 1 + the position of last '>' without '?' // before it. Usually the packet wrapper end is "<?xpacket end="w"?>. size_t GetXmpContentEnd(const string& data) { if (data.empty()) { return 0; } for (size_t i = data.size() - 1; i >= 1; --i) { if (data[i] == '>') { if (data[i - 1] != '?') { return i + 1; } } } // It should not reach here for a valid XMP meta. LOG(WARNING) << "Failed to find the end of the XMP meta content."; return data.size(); } // True if 's' starts with substring 'x'. bool StartsWith(const string& s, const string& x) { return s.size() >= x.size() && !s.compare(0, x.size(), x); } // True if 's' ends with substring 'x'. bool EndsWith(const string& s, const string& x) { return s.size() >= x.size() && !s.compare(s.size() - x.size(), x.size(), x); } // Parses the first valid XMP section. Any other valid XMP section will be // ignored. bool ParseFirstValidXMPSection(const std::vector<Section>& sections, XmpData* xmp) { for (const Section& section : sections) { if (StartsWith(section.data, XmpConst::Header())) { const size_t end = GetXmpContentEnd(section.data); // Increment header length by 1 for the null termination. const size_t header_length = strlen(XmpConst::Header()) + 1; // Check for integer underflow before subtracting. if (header_length >= end) { LOG(ERROR) << "Invalid content length: " << static_cast<int>(end - header_length); return false; } const size_t content_length = end - header_length; // header_length is guaranteed to be <= data.size due to the if condition // above. If this contract changes we must add an additonal check. const char* content_start = §ion.data[header_length]; // xmlReadMemory requires an int. Before casting size_t to int we must // check for integer overflow. if (content_length > INT_MAX) { LOG(ERROR) << "First XMP section too large, size: " << content_length; return false; } *xmp->MutableStandardSection() = xmlReadMemory( content_start, static_cast<int>(content_length), nullptr, nullptr, 0); if (xmp->StandardSection() == nullptr) { LOG(WARNING) << "Failed to parse standard section."; return false; } return true; } } return false; } // Collects the extended XMP sections with the given name into a string. Other // sections will be ignored. string GetExtendedXmpSections(const std::vector<Section>& sections, const string& section_name) { string extended_header = XmpConst::ExtensionHeader(); extended_header += '\0' + section_name; // section_name is dynamically extracted from the xml file and can have an // arbitrary size. Check for integer overflow before addition. if (extended_header.size() > SIZE_MAX - XmpConst::ExtensionHeaderOffset()) { return ""; } const size_t section_start_offset = extended_header.size() + XmpConst::ExtensionHeaderOffset(); // Compute the size of the buffer to parse the extended sections. std::vector<const Section*> xmp_sections; std::vector<size_t> xmp_end_offsets; size_t buffer_size = 0; for (const Section& section : sections) { if (extended_header.empty() || StartsWith(section.data, extended_header)) { const size_t end_offset = section.data.size(); const size_t section_size = end_offset - section_start_offset; if (end_offset < section_start_offset || section_size > SIZE_MAX - buffer_size) { return ""; } buffer_size += section_size; xmp_sections.push_back(§ion); xmp_end_offsets.push_back(end_offset); } } // Copy all the relevant sections' data into a buffer. string buffer(buffer_size, '\0'); if (buffer.size() != buffer_size) { return ""; } size_t offset = 0; for (int i = 0; i < xmp_sections.size(); ++i) { const Section* section = xmp_sections[i]; const size_t length = xmp_end_offsets[i] - section_start_offset; std::copy_n(§ion->data[section_start_offset], length, &buffer[offset]); offset += length; } return buffer; } // Parses the extended XMP sections with the given name. All other sections // will be ignored. bool ParseExtendedXmpSections(const std::vector<Section>& sections, const string& section_name, XmpData* xmp_data) { const string extended_sections = GetExtendedXmpSections(sections, section_name); // xmlReadMemory requires an int. Before casting size_t to int we must check // for integer overflow. if (extended_sections.size() > INT_MAX) { LOG(WARNING) << "Extended sections too large, size: " << extended_sections.size(); return false; } *xmp_data->MutableExtendedSection() = xmlReadMemory( extended_sections.data(), static_cast<int>(extended_sections.size()), nullptr, nullptr, XML_PARSE_HUGE); if (xmp_data->ExtendedSection() == nullptr) { LOG(WARNING) << "Failed to parse extended sections."; return false; } return true; } // Extracts a XmpData from a JPEG image stream. bool ExtractXmpMeta(const bool skip_extended, std::istream* file, XmpData* xmp_data) { // We cannot use CHECK because this is ported to AOSP. assert(xmp_data != nullptr); // NOLINT xmp_data->Reset(); ParseOptions parse_options; parse_options.read_meta_only = true; if (skip_extended) { parse_options.section_header = XmpConst::Header(); parse_options.section_header_return_first = true; } const std::vector<Section> sections = Parse(parse_options, file); if (sections.empty()) { LOG(WARNING) << "No sections found."; return false; } if (!ParseFirstValidXMPSection(sections, xmp_data)) { LOG(WARNING) << "Could not parse first section."; return false; } if (skip_extended) { return true; } string extension_name; DeserializerImpl deserializer( GetFirstDescriptionElement(xmp_data->StandardSection())); if (!deserializer.ParseString(XmpConst::HasExtensionPrefix(), XmpConst::HasExtension(), &extension_name)) { // No extended sections present, so nothing to parse. return true; } if (!ParseExtendedXmpSections(sections, extension_name, xmp_data)) { LOG(WARNING) << "Extended sections present, but could not be parsed."; return false; } return true; } // Extracts the specified string attribute. bool GetStringProperty(const xmlNodePtr node, const char* prefix, const char* property, string* value) { const xmlDocPtr doc = node->doc; for (const _xmlAttr* attribute = node->properties; attribute != nullptr; attribute = attribute->next) { if (attribute->ns && strcmp(FromXmlChar(attribute->ns->prefix), prefix) == 0 && strcmp(FromXmlChar(attribute->name), property) == 0) { xmlChar* attribute_string = xmlNodeListGetString(doc, attribute->children, 1); *value = FromXmlChar(attribute_string); xmlFree(attribute_string); return true; } } return false; } // Reads the contents of a node. // E.g. <prefix:node_name>Contents Here</prefix:node_name> bool ReadNodeContent(const xmlNodePtr node, const char* prefix, const char* node_name, string* value) { auto* element = DepthFirstSearch(node, node_name); if (element == nullptr) { return false; } if (prefix != nullptr && (element->ns == nullptr || element->ns->prefix == nullptr || strcmp(FromXmlChar(element->ns->prefix), prefix) != 0)) { return false; } xmlChar* node_content = xmlNodeGetContent(element); *value = FromXmlChar(node_content); free(node_content); return true; } template <typename T> bool ConvertStringPropertyToType(const string& string_property, T* value) { QCHECK(value) << "Cannot call this method on a generic type"; return false; } template <> bool ConvertStringPropertyToType<bool>(const string& string_property, bool* value) { return BoolStringToBool(string_property, value); } template <> bool ConvertStringPropertyToType<double>(const string& string_property, double* value) { *value = std::stod(string_property); return true; } template <> bool ConvertStringPropertyToType<int>(const string& string_property, int* value) { *value = 0; for (int i = 0; i < string_property.size(); ++i) { if (!isdigit(string_property[i])) { return false; } } *value = std::atoi(string_property.c_str()); // NOLINT return true; } template <> bool ConvertStringPropertyToType<int64>(const string& string_property, int64* value) { *value = std::stol(string_property); return true; } } // namespace bool ReadXmpHeader(const string& filename, const bool skip_extended, XmpData* xmp_data) { string filename_lower = filename; std::transform(filename_lower.begin(), filename_lower.end(), filename_lower.begin(), ::tolower); if (!EndsWith(filename_lower, kJpgExtension) && !EndsWith(filename_lower, kJpegExtension)) { LOG(WARNING) << "XMP parse: only JPEG file is supported"; return false; } std::ifstream file(filename.c_str(), std::ios::binary); if (!file.is_open()) { LOG(WARNING) << " Could not read file: " << filename; return false; } return ExtractXmpMeta(skip_extended, &file, xmp_data); } bool ReadXmpFromMemory(const string& jpeg_contents, const bool skip_extended, XmpData* xmp_data) { std::istringstream stream(jpeg_contents); return ExtractXmpMeta(skip_extended, &stream, xmp_data); } bool ReadXmpHeader(std::istream* input_stream, bool skip_extended, XmpData* xmp_data) { return ExtractXmpMeta(skip_extended, input_stream, xmp_data); } } // namespace xmpmeta } // namespace dynamic_depth