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/*
* Copyright 2015 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "cobalt/renderer/rasterizer/skia/skia/src/ports/SkFontConfigParser_cobalt.h"
#include <libxml/parser.h>
#include <limits>
#include <stack>
#include <string>
#include "base/memory/scoped_ptr.h"
#include "base/string_util.h"
#include "base/stringprintf.h"
#include "SkOSFile.h"
#include "SkTSearch.h"
namespace {
const char* kSystemFontsFile = "fonts.xml";
/////////////////////////////////////////////////////////////////////////////
// Helpers
/////////////////////////////////////////////////////////////////////////////
std::string StringPrintVAndTrim(const char* message, va_list arguments) {
const std::string formatted_message = base::StringPrintV(message, arguments);
std::string trimmed_message;
TrimWhitespace(formatted_message, TRIM_ALL, &trimmed_message);
return trimmed_message;
}
// https://www.w3.org/TR/html-markup/datatypes.html#common.data.integer.non-negative-def
template <typename T>
bool ParseNonNegativeInteger(const char* s, T* value) {
SK_COMPILE_ASSERT(std::numeric_limits<T>::is_integer, T_must_be_integer);
const T n_max = std::numeric_limits<T>::max() / 10;
const T d_max = std::numeric_limits<T>::max() - (n_max * 10);
T n = 0;
for (; *s; ++s) {
// Check if digit
if (!IsAsciiDigit(*s)) {
return false;
}
int d = *s - '0';
// Check for overflow
if (n > n_max || (n == n_max && d > d_max)) {
SkDebugf("---- ParseNonNegativeInteger error: overflow)");
return false;
}
n = (n * 10) + d;
}
*value = n;
return true;
}
// The page range list is a comma-delimited list of character page ranges. Each
// page range can either consist of either a single integer value, or a pair of
// values separated by a hyphen (representing the min and max value of the
// range). All page values must fall between 0 and kMaxPageValue. Additionally,
// the page ranges must be provided in ascending order. Any failure to meet
// these expectations will result in a parsing error.
bool ParsePageRangeList(const char* s, font_character_map::PageRanges* ranges) {
const int16 n_max = font_character_map::kMaxPageValue / 10;
const int16 d_max = font_character_map::kMaxPageValue - (n_max * 10);
int16 last_max = -1;
while (*s) {
font_character_map::PageRange range_value;
// Skip whitespace
while (IsAsciiWhitespace(*s)) {
++s;
if (!*s) {
return true;
}
}
for (int i = 0; i <= 1; ++i) {
if (!IsAsciiDigit(*s)) {
SkDebugf("---- ParsePageRangeList error: non-ascii digit page range");
return false;
}
int16 n = 0;
for (; *s; ++s) {
if (!IsAsciiDigit(*s)) {
break;
}
int d = *s - '0';
// Check for overflow
if (n > n_max || (n == n_max && d > d_max)) {
SkDebugf("---- ParsePageRangeList error: page range overflow");
return false;
}
n = (n * 10) + d;
}
if (i == 0) {
// Verify that this new range is larger than the previously encountered
// max. Ranges must appear in order. If it isn't, then the parsing has
// failed.
if (last_max >= n) {
SkDebugf("---- ParsePageRangeList error: pages unordered");
return false;
}
range_value.first = n;
if (*s && *s == '-') {
++s;
continue;
} else {
last_max = n;
range_value.second = n;
ranges->push_back(range_value);
break;
}
} else {
if (range_value.first <= n) {
last_max = n;
range_value.second = n;
ranges->push_back(range_value);
} else {
SkDebugf("---- ParsePageRangeList error: page range flipped");
return false;
}
}
}
if (*s) {
// Skip whitespace
while (IsAsciiWhitespace(*s)) {
++s;
if (!*s) {
return true;
}
}
if (*s == ',') {
++s;
} else {
SkDebugf("---- ParsePageRangeList error: invalid character");
return false;
}
}
}
return true;
}
/////////////////////////////////////////////////////////////////////////////
// Libxml SAX Handlers
/////////////////////////////////////////////////////////////////////////////
typedef unsigned char xmlChar;
void StartElement(void* context, const xmlChar* name,
const xmlChar** attribute_pairs);
void EndElement(void* context, const xmlChar* name);
void Characters(void* context, const xmlChar* ch, int len);
void ParserWarning(void* context, const char* message, ...);
void ParserError(void* context, const char* message, ...);
void ParserFatal(void* context, const char* message, ...);
xmlSAXHandler xml_sax_handler = {
NULL, /* internalSubset */
NULL, /* isStandalone */
NULL, /* hasInternalSubset */
NULL, /* hasExternalSubset */
NULL, /* resolveEntity */
NULL, /* getEntity */
NULL, /* entityDecl */
NULL, /* notationDecl */
NULL, /* attributeDecl */
NULL, /* elementDecl */
NULL, /* unparsedEntityDecl */
NULL, /* setDocumentLocator */
NULL, /* startDocument */
NULL, /* endDocument */
&StartElement, /* startElement */
&EndElement, /* endElement */
NULL, /* reference */
&Characters, /* characters */
NULL, /* ignorableWhitespace */
NULL, /* processingInstruction */
NULL, /* comment */
&ParserWarning, /* xmlParserWarning */
&ParserError, /* xmlParserError */
&ParserFatal, /* xmlParserFatalError */
NULL, /* getParameterEntity */
NULL, /* cdataBlock */
NULL, /* externalSubset */
1, /* initialized */
NULL, /* private */
NULL, /* startElementNsSAX2Func */
NULL, /* endElementNsSAX2Func */
NULL /* xmlStructuredErrorFunc */
};
enum ElementType {
kFamilyElementType,
kFontElementType,
kAliasElementType,
kOtherElementType,
};
// The FamilyData structure is passed around by the parser so that each handler
// can read these variables that are relevant to the current parsing.
struct FamilyData {
explicit FamilyData(SkTDArray<FontFamily*>* families_array)
: families(families_array), current_font_info(NULL) {}
// The array that each family is put into as it is parsed
SkTDArray<FontFamily*>* families;
// The current family being created. FamilyData owns this object while it is
// not NULL.
scoped_ptr<FontFamily> current_family;
// The current fontInfo being created. It is owned by FontFamily.
FontFileInfo* current_font_info;
std::stack<ElementType> element_stack;
};
void FamilyElementHandler(FontFamily* family, const char** attributes) {
if (attributes == NULL) {
return;
}
// A <family> tag must have a canonical name attribute, a fallback attribute
// set to true, or both in order to be usable. If it is a fallback family,
// then it may have lang and pages attributes for use during fallback.
for (size_t i = 0; attributes[i] != NULL && attributes[i + 1] != NULL;
i += 2) {
const char* name = attributes[i];
const char* value = attributes[i + 1];
size_t name_len = strlen(name);
if (name_len == 4 && strncmp(name, "name", name_len) == 0) {
SkAutoAsciiToLC to_lowercase(value);
family->names.push_back().set(to_lowercase.lc());
} else if (name_len == 4 && strncmp("lang", name, name_len) == 0) {
family->language = SkLanguage(value);
} else if (name_len == 5 && strncmp("pages", name, name_len) == 0) {
if (!ParsePageRangeList(value, &family->page_ranges)) {
SkDebugf("---- Page ranges %s (INVALID)", value);
family->page_ranges.reset();
}
} else if (name_len == 8 && strncmp("fallback", name, name_len) == 0) {
family->is_fallback_font =
strcmp("true", value) == 0 || strcmp("1", value) == 0;
}
}
}
void FontElementHandler(FontFileInfo* file, const char** attributes) {
DCHECK(file != NULL);
// A <font> should have following attributes:
// weight (integer), style (normal, italic), font_name (string), and
// postscript_name (string).
// The element should contain a filename.
enum SeenAttributeFlags {
kSeenNone = 0,
kSeenFontFullName = 1,
kSeenFontPostscriptName = 1 << 1,
kSeenWeight = 1 << 2,
kSeenStyle = 1 << 3
};
uint32_t seen_attributes_flag = kSeenNone;
for (size_t i = 0; attributes[i] != NULL && attributes[i + 1] != NULL;
i += 2) {
const char* name = attributes[i];
const char* value = attributes[i + 1];
switch (strlen(name)) {
case 9:
if (strncmp("font_name", name, 9) == 0) {
file->full_font_name = value;
seen_attributes_flag |= kSeenFontFullName;
continue;
}
break;
case 15:
if (strncmp("postscript_name", name, 15) == 0) {
file->postcript_name = value;
seen_attributes_flag |= kSeenFontPostscriptName;
continue;
}
break;
case 6:
if (strncmp("weight", name, 6) == 0) {
if (!ParseNonNegativeInteger(value, &file->weight)) {
DLOG(WARNING) << "Invalid font weight [" << value << "]";
file->weight = 0;
} else {
seen_attributes_flag |= kSeenWeight;
}
continue;
}
break;
case 5:
if (strncmp("style", name, 5) == 0) {
if (strncmp("italic", value, 6) == 0) {
file->style = FontFileInfo::kItalic_FontStyle;
seen_attributes_flag |= kSeenStyle;
continue;
} else if (strncmp("normal", value, 6) == 0) {
file->style = FontFileInfo::kNormal_FontStyle;
seen_attributes_flag |= kSeenStyle;
continue;
} else {
NOTREACHED() << "Unsupported style [" << value << "]";
}
}
break;
default:
break;
}
NOTREACHED() << "Unsupported attribute [" << name << "]";
}
DCHECK_EQ(seen_attributes_flag, kSeenFontFullName | kSeenFontPostscriptName |
kSeenWeight | kSeenStyle);
DCHECK(!file->full_font_name.isEmpty());
DCHECK(!file->postcript_name.isEmpty());
}
FontFamily* FindFamily(FamilyData* family_data, const char* family_name) {
size_t name_len = strlen(family_name);
for (int i = 0; i < family_data->families->count(); i++) {
FontFamily* candidate = (*family_data->families)[i];
for (int j = 0; j < candidate->names.count(); j++) {
if (!strncmp(candidate->names[j].c_str(), family_name, name_len) &&
name_len == strlen(candidate->names[j].c_str())) {
return candidate;
}
}
}
return NULL;
}
void AliasElementHandler(FamilyData* family_data, const char** attributes) {
// An <alias> must have name and to attributes.
// It may have weight (integer).
// If it *does not* have a weight, it is a variant name for a <family>.
// If it *does* have a weight, it names the <font>(s) of a specific weight
// from a <family>.
SkString alias_name;
SkString to;
for (size_t i = 0; attributes[i] != NULL && attributes[i + 1] != NULL;
i += 2) {
const char* name = attributes[i];
const char* value = attributes[i + 1];
size_t name_len = strlen(name);
if (name_len == 4 && strncmp("name", name, name_len) == 0) {
SkAutoAsciiToLC to_lowercase(value);
alias_name.set(to_lowercase.lc());
} else if (name_len == 2 && strncmp("to", name, name_len) == 0) {
to.set(value);
}
}
// Assumes that the named family is already declared
FontFamily* target_family = FindFamily(family_data, to.c_str());
if (!target_family) {
SkDebugf("---- Font alias target %s (NOT FOUND)", to.c_str());
return;
} else if (alias_name.size() == 0) {
SkDebugf("---- Font alias name for %s (NOT SET)", to.c_str());
return;
}
target_family->names.push_back().set(alias_name);
}
bool FindWeight400(FontFamily* family) {
for (int i = 0; i < family->fonts.count(); i++) {
if (family->fonts[i].weight == 400) {
return true;
}
}
return false;
}
bool DesiredWeight(int weight) { return (weight == 400 || weight == 700); }
int CountDesiredWeight(FontFamily* family) {
int count = 0;
for (int i = 0; i < family->fonts.count(); i++) {
if (DesiredWeight(family->fonts[i].weight)) {
count++;
}
}
return count;
}
// To meet Skia's expectations, any family that contains weight=400
// fonts should *only* contain {400,700}
void PurgeUndesiredWeights(FontFamily* family) {
int count = CountDesiredWeight(family);
for (int i = 1, j = 0; i < family->fonts.count(); i++) {
if (DesiredWeight(family->fonts[j].weight)) {
j++;
}
if ((i != j) && DesiredWeight(family->fonts[i].weight)) {
family->fonts[j] = family->fonts[i];
}
}
family->fonts.resize_back(count);
}
void FamilySetElementEndHandler(FamilyData* familyData) {
for (int i = 0; i < familyData->families->count(); i++) {
if (FindWeight400((*familyData->families)[i])) {
PurgeUndesiredWeights((*familyData->families)[i]);
}
}
}
void StartElement(void* data, const xmlChar* xml_tag,
const xmlChar** xml_attribute_pairs) {
FamilyData* family_data = reinterpret_cast<FamilyData*>(data);
const char* tag = reinterpret_cast<const char*>(xml_tag);
const char** attribute_pairs =
reinterpret_cast<const char**>(xml_attribute_pairs);
size_t tag_len = strlen(tag);
if (tag_len == 6 && strncmp("family", tag, tag_len) == 0) {
family_data->element_stack.push(kFamilyElementType);
family_data->current_family = make_scoped_ptr(new FontFamily());
FamilyElementHandler(family_data->current_family.get(), attribute_pairs);
} else if (tag_len == 4 && strncmp("font", tag, tag_len) == 0) {
family_data->element_stack.push(kFontElementType);
FontFileInfo* file = &family_data->current_family->fonts.push_back();
family_data->current_font_info = file;
FontElementHandler(file, attribute_pairs);
} else if (tag_len == 5 && strncmp("alias", tag, tag_len) == 0) {
family_data->element_stack.push(kAliasElementType);
AliasElementHandler(family_data, attribute_pairs);
} else {
family_data->element_stack.push(kOtherElementType);
}
}
void EndElement(void* data, const xmlChar* xml_tag) {
FamilyData* family_data = reinterpret_cast<FamilyData*>(data);
const char* tag = reinterpret_cast<const char*>(xml_tag);
size_t tag_len = strlen(tag);
if (tag_len == 9 && strncmp("familyset", tag, tag_len) == 0) {
FamilySetElementEndHandler(family_data);
} else if (tag_len == 6 && strncmp("family", tag, tag_len) == 0) {
if (family_data->current_family != NULL) {
*family_data->families->append() = family_data->current_family.release();
} else {
SkDebugf("---- Encountered end family tag with no current family");
}
}
family_data->element_stack.pop();
}
void Characters(void* data, const xmlChar* xml_characters, int len) {
FamilyData* family_data = reinterpret_cast<FamilyData*>(data);
const char* characters = reinterpret_cast<const char*>(xml_characters);
if (family_data->element_stack.size() > 0 &&
family_data->element_stack.top() == kFontElementType) {
family_data->current_font_info->file_name.set(characters, len);
}
}
void ParserWarning(void* context, const char* message, ...) {
va_list arguments;
va_start(arguments, message);
SkDebugf("---- Parsing warning: %s",
StringPrintVAndTrim(message, arguments).c_str());
}
void ParserError(void* context, const char* message, ...) {
va_list arguments;
va_start(arguments, message);
SkDebugf("---- Parsing error: %s",
StringPrintVAndTrim(message, arguments).c_str());
}
void ParserFatal(void* context, const char* message, ...) {
va_list arguments;
va_start(arguments, message);
SkDebugf("---- Parsing fatal error: %s",
StringPrintVAndTrim(message, arguments).c_str());
}
// This function parses the given filename and stores the results in the given
// families array.
void ParseConfigFile(const char* directory, const char* filename,
SkTDArray<FontFamily*>* families) {
SkString file_path = SkOSPath::Join(directory, filename);
FILE* file = fopen(file_path.c_str(), "r");
if (NULL == file) {
SkDebugf("---- Failed to open %s", file_path.c_str());
return;
}
FamilyData family_data(families);
xmlParserCtxtPtr xml_parser_context =
xmlCreatePushParserCtxt(&xml_sax_handler, &family_data, NULL, 0, NULL);
if (!xml_parser_context) {
SkDebugf("---- Unable to create parsing context!");
return;
}
char buffer[512];
bool done = false;
while (!done) {
fgets(buffer, sizeof(buffer), file);
size_t len = strlen(buffer);
if (feof(file) != 0) {
done = true;
}
xmlParseChunk(xml_parser_context, buffer, static_cast<int>(len),
0 /*do not terminate*/);
}
xmlParseChunk(xml_parser_context, NULL, 0, 1 /*terminate*/);
xmlFreeParserCtxt(xml_parser_context);
fclose(file);
}
void GetSystemFontFamilies(const char* directory,
SkTDArray<FontFamily*>* font_families) {
ParseConfigFile(directory, kSystemFontsFile, font_families);
}
} // namespace
namespace SkFontConfigParser {
// Loads data on font families from the configuration file. The resulting data
// is returned in the given fontFamilies array.
void GetFontFamilies(const char* directory,
SkTDArray<FontFamily*>* font_families) {
GetSystemFontFamilies(directory, font_families);
}
} // namespace SkFontConfigParser