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#include "markdown.h"
#include <yql/essentials/utils/yql_panic.h>
#include <contrib/libs/re2/re2/re2.h>
#include <util/generic/yexception.h>
#include <util/charset/utf8.h>
namespace NYql::NDocs {
class TMarkdownParser {
private:
static constexpr TStringBuf HeaderRegex = R"re(([^#]+)(\s+{#([a-z0-9\-_]+)})?)re";
public:
explicit TMarkdownParser(size_t headerDepth)
: HeaderDepth_(headerDepth)
, SectionHeaderRegex_(" *" + TString(HeaderDepth_, '#') + " " + HeaderRegex)
, IsSkipping_(true)
{
}
void Parse(IInputStream& markdown, TMarkdownCallback&& onSection) {
for (TString line; markdown.ReadLine(line) != 0;) {
size_t depth = HeaderDepth(line);
if (IsSkipping_) {
if (HeaderDepth_ == depth) {
ResetSection(std::move(line));
IsSkipping_ = false;
} else {
// Skip
}
} else {
if (HeaderDepth_ == depth) {
onSection(std::move(Section_));
ResetSection(std::move(line));
} else if (depth == 0 || HeaderDepth_ < depth) {
line.append('\n');
Section_.Body.append(std::move(line));
} else {
onSection(std::move(Section_));
IsSkipping_ = true;
}
}
}
if (!IsSkipping_) {
onSection(std::move(Section_));
}
}
private:
void ResetSection(TString&& line) {
Section_ = TMarkdownSection();
TString content;
std::optional<TString> dummy;
std::optional<TString> anchor;
if (!RE2::FullMatch(line, SectionHeaderRegex_, &content, &dummy, &anchor)) {
Section_.Header.Content = std::move(line);
return;
}
Section_.Header.Content = std::move(content);
if (anchor) {
Section_.Header.Anchor = std::move(*anchor);
}
}
size_t HeaderDepth(TStringBuf line) const {
while (line.StartsWith(' ') || line.StartsWith('\t')) {
line.Skip(1);
}
if (!line.StartsWith('#')) {
return 0;
}
size_t begin = line.find('#');
size_t end = line.find_first_not_of('#', begin);
return end != TStringBuf::npos ? (end - begin) : 0;
}
size_t HeaderDepth_;
RE2 SectionHeaderRegex_;
bool IsSkipping_;
TMarkdownSection Section_;
};
TMaybe<TString> Anchor(const TMarkdownHeader& header) {
static RE2 Regex(R"re([0-9a-z\-_]+)re");
if (header.Anchor) {
return header.Anchor;
}
TString content = ToLowerUTF8(header.Content);
SubstGlobal(content, ' ', '-');
if (RE2::FullMatch(content, Regex)) {
return content;
}
return Nothing();
}
TMarkdownPage ParseMarkdownPage(TString markdown) {
TMarkdownPage page;
const auto onSection = [&](TMarkdownSection&& section) {
if (TMaybe<TString> anchor = Anchor(section.Header)) {
section.Header.Anchor = anchor;
page.SectionsByAnchor[*anchor] = std::move(section);
}
};
{
TMarkdownParser parser(/*headerDepth=*/2);
TStringStream stream(markdown);
parser.Parse(stream, onSection);
}
{
TMarkdownParser parser(/*headerDepth=*/3);
TStringStream stream(markdown);
parser.Parse(stream, onSection);
}
page.Text = std::move(markdown);
return page;
}
} // namespace NYql::NDocs
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