SkFontMgr_android_parser.cpp File Reference

#include "include/core/SkFontMgr.h"
#include "include/core/SkStream.h"
#include "include/private/base/SkFixed.h"
#include "include/private/base/SkMalloc.h"
#include "include/private/base/SkTDArray.h"
#include "include/private/base/SkTLogic.h"
#include "include/private/base/SkTemplates.h"
#include "src/base/SkTSearch.h"
#include "src/core/SkOSFile.h"
#include "src/ports/SkFontMgr_android_parser.h"
#include <expat.h>
#include <stdlib.h>
#include <string.h>
#include <memory>

Go to the source code of this file.

Classes
struct	TagHandler
struct	FamilyData

Namespaces
namespace	lmpParser
namespace	jbParser

Macros
#define	LMP_SYSTEM_FONTS_FILE   "/system/etc/fonts.xml"
#define	OLD_SYSTEM_FONTS_FILE   "/system/etc/system_fonts.xml"
#define	FALLBACK_FONTS_FILE   "/system/etc/fallback_fonts.xml"
#define	VENDOR_FONTS_FILE   "/vendor/etc/fallback_fonts.xml"
#define	LOCALE_FALLBACK_FONTS_SYSTEM_DIR   "/system/etc"
#define	LOCALE_FALLBACK_FONTS_VENDOR_DIR   "/vendor/etc"
#define	LOCALE_FALLBACK_FONTS_PREFIX   "fallback_fonts-"
#define	LOCALE_FALLBACK_FONTS_SUFFIX   ".xml"
#define	SK_FONT_FILE_PREFIX   "/fonts/"
#define	MEMEQ(c, s, n)   memeq(c, s, sizeof(c) - 1, n)
#define	ATTS_NON_NULL(a, i)   (a[i] != nullptr && a[i+1] != nullptr)
#define	SK_FONTMGR_ANDROID_PARSER_PREFIX   "[SkFontMgr Android Parser] "
#define	SK_FONTCONFIGPARSER_WARNING(message, ...)

Functions
static bool	memeq (const char *s1, const char *s2, size_t n1, size_t n2)
static bool	is_whitespace (char c)
static void	trim_string (SkString *s)
static void	parse_space_separated_languages (const char *value, size_t valueLen, TArray< SkLanguage, true > &languages)
static FontFamily *	lmpParser::find_family (FamilyData *self, const SkString &familyName)
static void XMLCALL	start_element_handler (void *data, const char *tag, const char **attributes)
static void XMLCALL	end_element_handler (void *data, const char *tag)
static void XMLCALL	xml_entity_decl_handler (void *data, const XML_Char *entityName, int is_parameter_entity, const XML_Char *value, int value_length, const XML_Char *base, const XML_Char *systemId, const XML_Char *publicId, const XML_Char *notationName)
static int	parse_config_file (const char *filename, SkTDArray< FontFamily * > &families, const SkString &basePath, bool isFallback)
static int	append_system_font_families (SkTDArray< FontFamily * > &fontFamilies, const SkString &basePath)
static void	append_fallback_font_families_for_locale (SkTDArray< FontFamily * > &fallbackFonts, const char *dir, const SkString &basePath)
static void	append_system_fallback_font_families (SkTDArray< FontFamily * > &fallbackFonts, const SkString &basePath)
static void	mixin_vendor_fallback_font_families (SkTDArray< FontFamily * > &fallbackFonts, const SkString &basePath)

Variables
static const TagHandler	lmpParser::axisHandler
static const TagHandler	lmpParser::fontHandler
static const TagHandler	lmpParser::familyHandler
static const TagHandler	lmpParser::aliasHandler
static const TagHandler	lmpParser::familySetHandler
static const TagHandler	jbParser::fileHandler
static const TagHandler	jbParser::fileSetHandler
static const TagHandler	jbParser::nameHandler
static const TagHandler	jbParser::nameSetHandler
static const TagHandler	jbParser::familyHandler
static const TagHandler	jbParser::familySetHandler
static const TagHandler	topLevelHandler
static const XML_Memory_Handling_Suite	sk_XML_alloc

Macro Definition Documentation

ATTS_NON_NULL

#define ATTS_NON_NULL	(		a,
			i
	)		(a[i] != nullptr && a[i+1] != nullptr)

Definition at line 127 of file SkFontMgr_android_parser.cpp.

FALLBACK_FONTS_FILE

#define FALLBACK_FONTS_FILE   "/system/etc/fallback_fonts.xml"

Definition at line 32 of file SkFontMgr_android_parser.cpp.

LMP_SYSTEM_FONTS_FILE

#define LMP_SYSTEM_FONTS_FILE   "/system/etc/fonts.xml"

Definition at line 30 of file SkFontMgr_android_parser.cpp.

LOCALE_FALLBACK_FONTS_PREFIX

#define LOCALE_FALLBACK_FONTS_PREFIX   "fallback_fonts-"

Definition at line 37 of file SkFontMgr_android_parser.cpp.

LOCALE_FALLBACK_FONTS_SUFFIX

#define LOCALE_FALLBACK_FONTS_SUFFIX   ".xml"

Definition at line 38 of file SkFontMgr_android_parser.cpp.

LOCALE_FALLBACK_FONTS_SYSTEM_DIR

#define LOCALE_FALLBACK_FONTS_SYSTEM_DIR   "/system/etc"

Definition at line 35 of file SkFontMgr_android_parser.cpp.

LOCALE_FALLBACK_FONTS_VENDOR_DIR

#define LOCALE_FALLBACK_FONTS_VENDOR_DIR   "/vendor/etc"

Definition at line 36 of file SkFontMgr_android_parser.cpp.

MEMEQ

#define MEMEQ	(		c,
			s,
			n
	)		memeq(c, s, sizeof(c) - 1, n)

Definition at line 125 of file SkFontMgr_android_parser.cpp.

OLD_SYSTEM_FONTS_FILE

#define OLD_SYSTEM_FONTS_FILE   "/system/etc/system_fonts.xml"

Definition at line 31 of file SkFontMgr_android_parser.cpp.

SK_FONT_FILE_PREFIX

#define SK_FONT_FILE_PREFIX   "/fonts/"

Definition at line 41 of file SkFontMgr_android_parser.cpp.

SK_FONTCONFIGPARSER_WARNING

#define SK_FONTCONFIGPARSER_WARNING	(		message,
			...
	)

Value:

    SkDebugf(SK_FONTMGR_ANDROID_PARSER_PREFIX "%s:%d:%d: warning: " message "\n", \
             self->fFilename,                                                     \
             (int)XML_GetCurrentLineNumber(self->fParser),                        \
             (int)XML_GetCurrentColumnNumber(self->fParser),                      \
             ##__VA_ARGS__)

Definition at line 131 of file SkFontMgr_android_parser.cpp.

                                                 :%d:%d: warning: " message "\n", \
             self->fFilename,                                                     \
             (int)XML_GetCurrentLineNumber(self->fParser),                        \
             (int)XML_GetCurrentColumnNumber(self->fParser),                      \
             ##__VA_ARGS__)

SK_FONTMGR_ANDROID_PARSER_PREFIX

#define SK_FONTMGR_ANDROID_PARSER_PREFIX   "[SkFontMgr Android Parser] "

Definition at line 129 of file SkFontMgr_android_parser.cpp.

VENDOR_FONTS_FILE

#define VENDOR_FONTS_FILE   "/vendor/etc/fallback_fonts.xml"

Definition at line 33 of file SkFontMgr_android_parser.cpp.

Function Documentation

append_fallback_font_families_for_locale()

static void append_fallback_font_families_for_locale ( SkTDArray< FontFamily * > &  fallbackFonts, const char *  dir, const SkString &  basePath  )

static

In some versions of Android prior to Android 4.2 (JellyBean MR1 at API Level 17) the fallback fonts for certain locales were encoded in their own XML files with a suffix that identified the locale. We search the provided directory for those files,add all of their entries to the fallback chain, and include the locale as part of each entry.

Definition at line 722 of file SkFontMgr_android_parser.cpp.

{
    SkOSFile::Iter iter(dir, nullptr);
    SkString fileName;
    while (iter.next(&fileName, false)) {
        // The size of the prefix and suffix.
        static const size_t fixedLen = sizeof(LOCALE_FALLBACK_FONTS_PREFIX) - 1
                                     + sizeof(LOCALE_FALLBACK_FONTS_SUFFIX) - 1;
 
        // The size of the prefix, suffix, and a minimum valid language code
        static const size_t minSize = fixedLen + 2;
 
        if (fileName.size() < minSize ||
            !fileName.startsWith(LOCALE_FALLBACK_FONTS_PREFIX) ||
            !fileName.endsWith(LOCALE_FALLBACK_FONTS_SUFFIX))
        {
            continue;
        }
 
        SkString locale(fileName.c_str() + sizeof(LOCALE_FALLBACK_FONTS_PREFIX) - 1,
                        fileName.size() - fixedLen);
 
        SkString absoluteFilename;
        absoluteFilename.printf("%s/%s", dir, fileName.c_str());
 
        SkTDArray<FontFamily*> langSpecificFonts;
        parse_config_file(absoluteFilename.c_str(), langSpecificFonts, basePath, true);
 
        for (int i = 0; i < langSpecificFonts.size(); ++i) {
            FontFamily* family = langSpecificFonts[i];
            family->fLanguages.emplace_back(locale);
            *fallbackFonts.append() = family;
        }
    }
}

append_system_fallback_font_families()

static void append_system_fallback_font_families ( SkTDArray< FontFamily * > &  fallbackFonts, const SkString &  basePath  )

static

Definition at line 760 of file SkFontMgr_android_parser.cpp.

{
    parse_config_file(FALLBACK_FONTS_FILE, fallbackFonts, basePath, true);
    append_fallback_font_families_for_locale(fallbackFonts,
                                             LOCALE_FALLBACK_FONTS_SYSTEM_DIR,
                                             basePath);
}

append_system_font_families()

static int append_system_font_families ( SkTDArray< FontFamily * > &  fontFamilies, const SkString &  basePath  )

static

Returns the version of the system font file actually found, negative if none.

Definition at line 704 of file SkFontMgr_android_parser.cpp.

{
    int initialCount = fontFamilies.size();
    int version = parse_config_file(LMP_SYSTEM_FONTS_FILE, fontFamilies, basePath, false);
    if (version < 0 || fontFamilies.size() == initialCount) {
        version = parse_config_file(OLD_SYSTEM_FONTS_FILE, fontFamilies, basePath, false);
    }
    return version;
}

end_element_handler()

static void XMLCALL end_element_handler ( void *  data, const char *  tag  )

static

Definition at line 601 of file SkFontMgr_android_parser.cpp.

                                                                     {
    FamilyData* self = static_cast<FamilyData*>(data);
    --self->fDepth;
 
    if (!self->fSkip) {
        const TagHandler* child = self->fHandler.back();
        if (child->end) {
            child->end(self, tag);
        }
        self->fHandler.pop_back();
        const TagHandler* parent = self->fHandler.back();
        XML_SetCharacterDataHandler(self->fParser, parent->chars);
    }
 
    if (self->fSkip == self->fDepth) {
        self->fSkip = 0;
        const TagHandler* parent = self->fHandler.back();
        XML_SetCharacterDataHandler(self->fParser, parent->chars);
    }
}

is_whitespace()

static bool is_whitespace ( char  c )

static

Definition at line 138 of file SkFontMgr_android_parser.cpp.

                                  {
    return c == ' ' || c == '\n'|| c == '\r' || c == '\t';
}

memeq()

static bool memeq ( const char *  s1, const char *  s2, size_t  n1, size_t  n2  )

static

Definition at line 122 of file SkFontMgr_android_parser.cpp.

                                                                        {
    return n1 == n2 && 0 == memcmp(s1, s2, n1);
}

mixin_vendor_fallback_font_families()

static void mixin_vendor_fallback_font_families ( SkTDArray< FontFamily * > &  fallbackFonts, const SkString &  basePath  )

static

Definition at line 769 of file SkFontMgr_android_parser.cpp.

{
    SkTDArray<FontFamily*> vendorFonts;
    parse_config_file(VENDOR_FONTS_FILE, vendorFonts, basePath, true);
    append_fallback_font_families_for_locale(vendorFonts,
                                             LOCALE_FALLBACK_FONTS_VENDOR_DIR,
                                             basePath);
 
    // This loop inserts the vendor fallback fonts in the correct order in the
    // overall fallbacks list.
    int currentOrder = -1;
    for (int i = 0; i < vendorFonts.size(); ++i) {
        FontFamily* family = vendorFonts[i];
        int order = family->fOrder;
        if (order < 0) {
            if (currentOrder < 0) {
                // Default case - just add it to the end of the fallback list
                *fallbackFonts.append() = family;
            } else {
                // no order specified on this font, but we're incrementing the order
                // based on an earlier order insertion request
                *fallbackFonts.insert(currentOrder++) = family;
            }
        } else {
            // Add the font into the fallback list in the specified order. Set
            // currentOrder for correct placement of other fonts in the vendor list.
            *fallbackFonts.insert(order) = family;
            currentOrder = order + 1;
        }
    }
}

parse_config_file()

static int parse_config_file ( const char *  filename, SkTDArray< FontFamily * > &  families, const SkString &  basePath, bool  isFallback  )

static

This function parses the given filename and stores the results in the given families array. Returns the version of the file, negative if the file does not exist.

Definition at line 647 of file SkFontMgr_android_parser.cpp.

{
    SkFILEStream file(filename);
 
    // Some of the files we attempt to parse (in particular, /vendor/etc/fallback_fonts.xml)
    // are optional - failure here is okay because one of these optional files may not exist.
    if (!file.isValid()) {
        SkDebugf(SK_FONTMGR_ANDROID_PARSER_PREFIX "'%s' could not be opened\n", filename);
        return -1;
    }
 
    SkAutoTCallVProc<std::remove_pointer_t<XML_Parser>, XML_ParserFree> parser(
        XML_ParserCreate_MM(nullptr, &sk_XML_alloc, nullptr));
    if (!parser) {
        SkDebugf(SK_FONTMGR_ANDROID_PARSER_PREFIX "could not create XML parser\n");
        return -1;
    }
 
    FamilyData self(parser, families, basePath, isFallback, filename, &topLevelHandler);
    XML_SetUserData(parser, &self);
 
    // Disable entity processing, to inhibit internal entity expansion. See expat CVE-2013-0340
    XML_SetEntityDeclHandler(parser, xml_entity_decl_handler);
 
    // Start parsing oldschool; switch these in flight if we detect a newer version of the file.
    XML_SetElementHandler(parser, start_element_handler, end_element_handler);
 
    // One would assume it would be faster to have a buffer on the stack and call XML_Parse.
    // But XML_Parse will call XML_GetBuffer anyway and memmove the passed buffer into it.
    // (Unless XML_CONTEXT_BYTES is undefined, but all users define it.)
    // In debug, buffer a small odd number of bytes to detect slicing in XML_CharacterDataHandler.
    static const int bufferSize = 512 SkDEBUGCODE( - 507);
    bool done = false;
    while (!done) {
        void* buffer = XML_GetBuffer(parser, bufferSize);
        if (!buffer) {
            SkDebugf(SK_FONTMGR_ANDROID_PARSER_PREFIX "could not buffer enough to continue\n");
            return -1;
        }
        size_t len = file.read(buffer, bufferSize);
        done = file.isAtEnd();
        XML_Status status = XML_ParseBuffer(parser, len, done);
        if (XML_STATUS_ERROR == status) {
            XML_Error error = XML_GetErrorCode(parser);
            int line = XML_GetCurrentLineNumber(parser);
            int column = XML_GetCurrentColumnNumber(parser);
            const XML_LChar* errorString = XML_ErrorString(error);
            SkDebugf(SK_FONTMGR_ANDROID_PARSER_PREFIX "%s:%d:%d error %d: %s.\n",
                     filename, line, column, error, errorString);
            return -1;
        }
    }
    return self.fVersion;
}

parse_space_separated_languages()

static void parse_space_separated_languages ( const char *  value, size_t  valueLen, TArray< SkLanguage, true > &  languages  )

static

Definition at line 157 of file SkFontMgr_android_parser.cpp.

{
    size_t i = 0;
    while (true) {
        for (; i < valueLen && is_whitespace(value[i]); ++i) { }
        if (i == valueLen) { break; }
        size_t j;
        for (j = i + 1; j < valueLen && !is_whitespace(value[j]); ++j) { }
        languages.emplace_back(value + i, j - i);
        i = j;
        if (i == valueLen) { break; }
    }
}

start_element_handler()

static void XMLCALL start_element_handler ( void *  data, const char *  tag, const char **  attributes  )

static

Definition at line 579 of file SkFontMgr_android_parser.cpp.

                                                                                                {
    FamilyData* self = static_cast<FamilyData*>(data);
 
    if (!self->fSkip) {
        const TagHandler* parent = self->fHandler.back();
        const TagHandler* child = parent->tag ? parent->tag(self, tag, attributes) : nullptr;
        if (child) {
            if (child->start) {
                child->start(self, tag, attributes);
            }
            self->fHandler.push_back(child);
            XML_SetCharacterDataHandler(self->fParser, child->chars);
        } else {
            SK_FONTCONFIGPARSER_WARNING("'%s' tag not recognized, skipping", tag);
            XML_SetCharacterDataHandler(self->fParser, nullptr);
            self->fSkip = self->fDepth;
        }
    }
 
    ++self->fDepth;
}

trim_string()

static void trim_string ( SkString *  s )

static

Definition at line 142 of file SkFontMgr_android_parser.cpp.

                                     {
    char* str = s->data();
    const char* start = str;  // start is inclusive
    const char* end = start + s->size();  // end is exclusive
    while (is_whitespace(*start)) { ++start; }
    if (start != end) {
        --end;  // make end inclusive
        while (is_whitespace(*end)) { --end; }
        ++end;  // make end exclusive
    }
    size_t len = end - start;
    memmove(str, start, len);
    s->resize(len);
}

xml_entity_decl_handler()

static void XMLCALL xml_entity_decl_handler ( void *  data, const XML_Char *  entityName, int  is_parameter_entity, const XML_Char *  value, int  value_length, const XML_Char *  base, const XML_Char *  systemId, const XML_Char *  publicId, const XML_Char *  notationName  )

static

Definition at line 622 of file SkFontMgr_android_parser.cpp.

{
    FamilyData* self = static_cast<FamilyData*>(data);
    SK_FONTCONFIGPARSER_WARNING("'%s' entity declaration found, stopping processing", entityName);
    XML_StopParser(self->fParser, XML_FALSE);
}

Variable Documentation

sk_XML_alloc

const XML_Memory_Handling_Suite sk_XML_alloc

static

Initial value:

= {
    sk_malloc_throw,
    sk_realloc_throw,
    sk_free
}

Definition at line 637 of file SkFontMgr_android_parser.cpp.

                                                      {
    sk_malloc_throw,
    sk_realloc_throw,
    sk_free
};

topLevelHandler

const TagHandler topLevelHandler

static

Initial value:

= {
    nullptr,
    nullptr,
    [](FamilyData* self, const char* tag, const char** attributes) -> const TagHandler* {
        size_t len = strlen(tag);
        if (MEMEQ("familyset", tag, len)) {
            
            for (size_t i = 0; ATTS_NON_NULL(attributes, i); i += 2) {
                const char* name = attributes[i];
                size_t nameLen = strlen(name);
                if (MEMEQ("version", name, nameLen)) {
                    const char* value = attributes[i+1];
                    if (parse_non_negative_integer(value, &self->fVersion)) {
                        if (self->fVersion >= 21) {
                            return &lmpParser::familySetHandler;
                        }
                    }
                }
            }
            return &jbParser::familySetHandler;
        }
        return nullptr;
    },
    nullptr,
}

Definition at line 553 of file SkFontMgr_android_parser.cpp.

                                          {
    /*start*/nullptr,
    /*end*/nullptr,
    /*tag*/[](FamilyData* self, const char* tag, const char** attributes) -> const TagHandler* {
        size_t len = strlen(tag);
        if (MEMEQ("familyset", tag, len)) {
            // 'version' (non-negative integer) [default 0]
            for (size_t i = 0; ATTS_NON_NULL(attributes, i); i += 2) {
                const char* name = attributes[i];
                size_t nameLen = strlen(name);
                if (MEMEQ("version", name, nameLen)) {
                    const char* value = attributes[i+1];
                    if (parse_non_negative_integer(value, &self->fVersion)) {
                        if (self->fVersion >= 21) {
                            return &lmpParser::familySetHandler;
                        }
                    }
                }
            }
            return &jbParser::familySetHandler;
        }
        return nullptr;
    },
    /*chars*/nullptr,
};