lix/src/libcmd/markdown.cc
sternenseemann d0e34c85f8 libcmd/markdown: handle allocation errors in lowdown_term_rndr
We upgrade to lowdown 0.8.0 [1] which contains a fix/improvement to a
behavior mentioned in this issue thread [2] where a big part of
lowdown's API would just call exit(1) on allocation errors since that
is a satisfying behavior for the lowdown binary.

Now lowdown_term_rndr returns 0 if an allocation error occurred which we
check for in libcmd/markdown.cc.

Also the extern "C" { } wrapper around lowdown.h has been removed as it
is not necessary.

[1]: 6ca7c855a0/versions.xml (L987-L1006)
[2]: https://github.com/kristapsdz/lowdown/issues/45#issuecomment-756681153
2021-02-06 13:14:57 +01:00

51 lines
1.4 KiB
C++

#include "markdown.hh"
#include "util.hh"
#include "finally.hh"
#include <sys/queue.h>
#include <lowdown.h>
namespace nix {
std::string renderMarkdownToTerminal(std::string_view markdown)
{
struct lowdown_opts opts {
.type = LOWDOWN_TERM,
.maxdepth = 20,
.cols = std::min(getWindowSize().second, (unsigned short) 80),
.hmargin = 0,
.vmargin = 0,
.feat = LOWDOWN_COMMONMARK | LOWDOWN_FENCED | LOWDOWN_DEFLIST | LOWDOWN_TABLES,
.oflags = 0,
};
auto doc = lowdown_doc_new(&opts);
if (!doc)
throw Error("cannot allocate Markdown document");
Finally freeDoc([&]() { lowdown_doc_free(doc); });
size_t maxn = 0;
auto node = lowdown_doc_parse(doc, &maxn, markdown.data(), markdown.size());
if (!node)
throw Error("cannot parse Markdown document");
Finally freeNode([&]() { lowdown_node_free(node); });
auto renderer = lowdown_term_new(&opts);
if (!renderer)
throw Error("cannot allocate Markdown renderer");
Finally freeRenderer([&]() { lowdown_term_free(renderer); });
auto buf = lowdown_buf_new(16384);
if (!buf)
throw Error("cannot allocate Markdown output buffer");
Finally freeBuffer([&]() { lowdown_buf_free(buf); });
int rndr_res = lowdown_term_rndr(buf, nullptr, renderer, node);
if (!rndr_res)
throw Error("allocation error while rendering Markdown");
return std::string(buf->data, buf->size);
}
}