Py-gfm

* [API change] Added `CUSTOM_BLOCK` and `CUSTOM_INLINE` node types.
They are never generated by the parser, and do not correspond
to CommonMark elements. They are designed to be inserted by
filters that postprocess the AST. For example, a filter might
convert specially marked code blocks to svg diagrams in HTML
and tikz diagrams in LaTeX, passing these through to the renderer
as a `CUSTOM_BLOCK`. These nodes can have children, but they
also have literal text to be printed by the renderer "on enter"
and "on exit." Added `cmark_node_get_on_enter`,
`cmark_node_set_on_enter`, `cmark_node_get_on_exit`,
`cmark_node_set_on_exit` to API.
* [API change] Rename `NODE_HTML` -> `NODE_HTML_BLOCK`,
`NODE_INLINE_HTML` -> `NODE_HTML_INLINE`. Define aliases
so the old names still work, for backwards compatibility.
* [API change] Rename `CMARK_NODE_HEADER` -> `CMARK_NODE_HEADING`.
Note that for backwards compatibility, we have defined aliases:
`CMARK_NODE_HEADER` = `CMARK_NODE_HEADING`,
`cmark_node_get_header_level` = `cmark_node_get_heading_level`, and
`cmark_node_set_header_level` = `cmark_node_set_heading_level`.
* [API change] Rename `CMARK_NODE_HRULE` -> `CMARK_NODE_THEMATIC_BREAK`.
Defined the former as the latter for backwards compatibility.
* Don't allow space between link text and link label in a reference link
(spec change).
* Separate parsing and rendering opts in `cmark.h` (88).
This change also changes some of these constants' numerical values,
but nothing should change in the API if you use the constants
themselves. It should now be clear in the man page which
options affect parsing and which affect rendering.
* xml renderer - Added xmlns attribute to document node (jgm/CommonMark87).
* Commonmark renderer: ensure html blocks surrounded by blanks.
Otherwise we get failures of roundtrip tests.
* Commonmark renderer: ensure that literal characters get escaped
when they're at the beginning of a block, e.g. `> \- foo`.
* LaTeX renderer - better handling of internal links.
Now we render `[foo](bar)` as `\protect\hyperlink{bar}{foo}`.
* Check for NULL pointer in _scan_at (81).
* `Makefile.nmake`: be more robust when cmake is missing. Previously,
when cmake was missing, the build dir would be created anyway, and
subsequent attempts (even with cmake) would fail, because cmake would
not be run. Depending on `build/CMakeFiles` is more robust -- this won't
be created unless cmake is run. Partially addresses 85.
* Fixed DOCTYPE in xml output.
* commonmark.c: fix `size_t` to `int`. This fixes an MSVC warning
"conversion from 'size_t' to 'int', possible loss of data" (Kevin Wojniak).
* Correct string length in `cmark_parse_document` example (Lee Jeffery).
* Fix non-ASCII end-of-line character check (andyuhnak).
* Fix "declaration shadows a local variable" (Kevin Wojniak).
* Install static library (jgm/CommonMark381).
* Fix warnings about dropping const qualifier (Kevin Wojniak).
* Use full (unabbreviated) versions of constants (`CMARK_...`).
* Removed outdated targets from Makefile.
* Removed need for sudo in `make bench`.
* Improved benchmark. Use longer test, since `time` has limited resolution.
* Removed `bench.h` and timing calls in `main.c`.
* Updated API docs; getters return empty strings if not set
rather than NULL, as previously documented.
* Added api_tests for custom nodes.
* Made roundtrip test part of the test suite run by cmake.
* Regenerate `scanners.c` using re2c 0.15.3.
* Adjusted scanner for link url. This fixes a heap buffer overflow (82).
* Added version number (1.0) to XML namespace. We don't guarantee
stability in this until 1.0 is actually released, however.
* Removed obsolete `TIMER` macro.
* Make `LIB_INSTALL_DIR` configurable (Mathieu Bridon, 79).
* Removed out-of-date luajit wrapper.
* Use `input`, not `parser->curline` to determine last line length.
* Small optimizations in `_scan_at`.
* Replaced hard-coded 4 with `TAB_STOP`.
* Have `make format` reformat api tests as well.
* Added api tests for man, latex, commonmark, and xml renderers (51).
* render.c: added `begin_content` field. This is like `begin_line` except
that it doesn't trigger production of the prefix. So it can be set
after an initial prefix (say `> `) is printed by the renderer, and
consulted in determining whether to escape content that has a special
meaning at the beginning of a line. Used in the commonmark renderer.
* Python 3.5 compatibility: don't require HTMLParseError (Zhiming Wang).
HTMLParseError was removed in Python 3.5. Since it could never be thrown
in Python 3.5+, we simply define a placeholder when HTMLParseError
cannot be imported.
* Set `convert_charrefs=False` in `normalize.py` (83). This defeats the
new default as of python 3.5, and allows the script to work with python
3.5.

* Removed `pre` from blocktags scanner. `pre` is handled separately
in rule 1 and needn't be handled in rule 6.
* Added `iframe` to list of blocktags, as per spec change.
* Fixed bug with `HRULE` after blank line. This previously caused cmark
to break out of a list, thinking it had two consecutive blanks.
* Check for empty string before trying to look at line ending.
* Make sure every line fed to `S_process_line` ends with `\n` (72).
So `S_process_line` sees only unix style line endings. Ultimately we
probably want a better solution, allowing the line ending style of
the input file to be preserved. This solution forces output with newlines.
* Improved `cmark_strbuf_normalize_whitespace` (73). Now all characters
that satisfy `cmark_isspace` are recognized as whitespace. Previously
`\r` and `\t` (and others) weren't included.
* Treat line ending with EOF as ending with newline (71).
* Fixed `--hardbreaks` with `\r\n` line breaks (68).
* Disallow list item starting with multiple blank lines (jgm/CommonMark332).
* Allow tabs before closing ``s in ATX header
* Removed `cmark_strbuf_printf` and `cmark_strbuf_vprintf`.
These are no longer needed, and cause complications for MSVC.
Also removed `HAVE_VA_COPY` and `HAVE_C99_SNPRINTF` feature tests.
* Added option to disable tests (Kevin Wojniak).
* Added `CMARK_INLINE` macro.
* Removed need to disable MSVC warnings 4267, 4244, 4800
(Kevin Wojniak).
* Fixed MSVC inline errors when cmark is included in sources that
don't have the same set of disabled warnings (Kevin Wojniak).
* Fix `FileNotFoundError` errors on tests when cmark is built from
another project via `add_subdirectory()` (Kevin Wojniak).
* Prefix `utf8proc` functions to avoid conflict with existing library
(Kevin Wojniak).
* Avoid name clash between Windows `.pdb` files (Nick Wellnhofer).
* Improved `smart_punct.txt` (see jgm/commonmark.js61).
* Set `POSITION_INDEPENDENT_CODE` `ON` for static library (see 39).
* `make bench`: allow overriding `BENCHFILE`. Previously if you did
this, it would clopper `BENCHFILE` with the default bench file.
* `make bench`: Use -10 priority with renice.
* Improved `make_autolink`. Ensures that title is chunk with empty
string rather than NULL, as with other links.
* Added `clang-check` target.
* Travis: split `roundtrip_test` and `leakcheck` (OGINO Masanori).
* Use clang-format, llvm style, for formatting. Reformatted all source files.
Added `format` target to Makefile. Removed `astyle` target.
Updated `.editorconfig`.

* Updated to version 0.21 of spec.
* Added latex renderer (31). New exported function in API:
`cmark_render_latex`. New source file: `src/latex.hs`.
* Updates for new HTML block spec. Removed old `html_block_tag` scanner.
Added new `html_block_start` and `html_block_start_7`, as well
as `html_block_end_n` for n = 1-5. Rewrote block parser for new HTML
block spec.
* We no longer preprocess tabs to spaces before parsing.
Instead, we keep track of both the byte offset and
the (virtual) column as we parse block starts.
This allows us to handle tabs without converting
to spaces first. Tabs are left as tabs in the output, as
per the revised spec.
* Removed utf8 validation by default. We now replace null characters
in the line splitting code.
* Added `CMARK_OPT_VALIDATE_UTF8` option and command-line option
`--validate-utf8`. This option causes cmark to check for valid
UTF-8, replacing invalid sequences with the replacement
character, U+FFFD. Previously this was done by default in
connection with tab expansion, but we no longer do it by
default with the new tab treatment. (Many applications will
know that the input is valid UTF-8, so validation will not
be necessary.)
* Added `CMARK_OPT_SAFE` option and `--safe` command-line flag.
+ Added `CMARK_OPT_SAFE`. This option disables rendering of raw HTML
and potentially dangerous links.
+ Added `--safe` option in command-line program.
+ Updated `cmark.3` man page.
+ Added `scan_dangerous_url` to scanners.
+ In HTML, suppress rendering of raw HTML and potentially dangerous
links if `CMARK_OPT_SAFE`. Dangerous URLs are those that begin
with `javascript:`, `vbscript:`, `file:`, or `data:` (except for
`image/png`, `image/gif`, `image/jpeg`, or `image/webp` mime types).
+ Added `api_test` for `OPT_CMARK_SAFE`.
+ Rewrote `README.md` on security.
* Limit ordered list start to 9 digits, per spec.
* Added width parameter to `render_man` (API change).
* Extracted common renderer code from latex, man, and commonmark
renderers into a separate module, `renderer.[ch]` (63). To write a
renderer now, you only need to write a character escaping function
and a node rendering function. You pass these to `cmark_render`
and it handles all the plumbing (including line wrapping) for you.
So far this is an internal module, but we might consider adding
it to the API in the future.
* commonmark writer: correctly handle email autolinks.
* commonmark writer: escape `!`.
* Fixed soft breaks in commonmark renderer.
* Fixed scanner for link url. re2c returns the longest match, so we
were getting bad results with `[link](foo\(and\(bar\)\))`
which it would parse as containing a bare `\` followed by
an in-parens chunk ending with the final paren.
* Allow non-initial hyphens in html tag names. This allows for
custom tags, see jgm/CommonMark239.
* Updated `test/smart_punct.txt`.
* Implemented new treatment of hyphens with `--smart`, converting
sequences of hyphens to sequences of em and en dashes that contain no
hyphens.
* HTML renderer: properly split info on first space char (see
jgm/commonmark.js54).
* Changed version variables to functions (60, Andrius Bentkus).
This is easier to access using ffi, since some languages, like C
like to use only function interfaces for accessing library
functionality.
* `process_emphasis`: Fixed setting lower bound to potential openers.
Renamed `potential_openers` -> `openers_bottom`.
Renamed `start_delim` -> `stack_bottom`.
* Added case for 59 to `pathological_test.py`.
* Fixed emphasis/link parsing bug (59).
* Fixed off-by-one error in line splitting routine.
This caused certain NULLs not to be replaced.
* Don't rtrim in `subject_from_buffer`. This gives bad results in
parsing reference links, where we might have trailing blanks
(`finalize` removes the bytes parsed as a reference definition;
before this change, some blank bytes might remain on the line).
+ Added `column` and `first_nonspace_column` fields to `parser`.
+ Added utility function to advance the offset, computing
the virtual column too. Note that we don't need to deal with
UTF-8 here at all. Only ASCII occurs in block starts.
+ Significant performance improvement due to the fact that
we're not doing UTF-8 validation.
* Fixed entity lookup table. The old one had many errors.
The new one is derived from the list in the npm entities package.
Since the sequences can now be longer (multi-code-point), we
have bumped the length limit from 4 to 8, which also affects
`houdini_html_u.c`. An example of the kind of error that was fixed:
`≧̸` should be rendered as "≧̸" (U+02267 U+00338), but it was
being rendered as "≧" (which is the same as `≧`).
* Replace gperf-based entity lookup with binary tree lookup.
The primary advantage is a big reduction in the size of
the compiled library and executable (> 100K).
There should be no measurable performance difference in
normal documents. I detected only a slight performance
hit in a file containing 1,000,000 entities.
+ Removed `src/html_unescape.gperf` and `src/html_unescape.h`.
+ Added `src/entities.h` (generated by `tools/make_entities_h.py`).
+ Added binary tree lookup functions to `houdini_html_u.c`, and
use the data in `src/entities.h`.
* Renamed `entities.h` -> `entities.inc`, and
`tools/make_entities_h.py` -> `tools/make_entitis_inc.py`.
* Fixed cases like

[ref]: url
"title" ok

Here we should parse the first line as a reference.
* `inlines.c`: Added utility functions to skip spaces and line endings.
* Fixed backslashes in link destinations that are not part of escapes
(jgm/commonmark45).
* `process_line`: Removed "add newline if line doesn't have one."
This isn't actually needed.
* Small logic fixes and a simplification in `process_emphasis`.
* Added more pathological tests:
+ Many link closers with no openers.
+ Many link openers with no closers.
+ Many emph openers with no closers.
+ Many closers with no openers.
+ `"*a_ " * 20000`.
* Fixed `process_emphasis` to handle new pathological cases.
Now we have an array of pointers (`potential_openers`),
keyed to the delim char. When we've failed to match a potential opener
prior to point X in the delimiter stack, we reset `potential_openers`
for that opener type to X, and thus avoid having to look again through
all the openers we've already rejected.
* `process_inlines`: remove closers from delim stack when possible.
When they have no matching openers and cannot be openers themselves,
we can safely remove them. This helps with a performance case:
`"a_ " * 20000` (jgm/commonmark.js43).
* Roll utf8proc_charlen into utf8proc_valid (Nick Wellnhofer).
Speeds up "make bench" by another percent.
* `spec_tests.py`: allow `→` for tab in HTML examples.
* `normalize.py`: don't collapse whitespace in pre contexts.
* Use utf-8 aware re2c.
* Makefile afl target: removed `-m none`, added `CMARK_OPTS`.
* README: added `make afl` instructions.
* Limit generated generated `cmark.3` to 72 character line width.
* Travis: switched to containerized build system.
* Removed `debug.h`. (It uses GNU extensions, and we don't need it anyway.)
* Removed sundown from benchmarks, because the reading was anomalous.
sundown had an arbitrary 16MB limit on buffers, and the benchmark
input exceeded that. So who knows what we were actually testing?
Added hoedown, sundown's successor, which is a better comparison.

* Fixed bug in list item parsing when items indented >= 4 spaces (52).
* Don't allow link labels with no non-whitespace characters
(jgm/CommonMark322).
* Fixed multiple issues with numeric entities (33, Nick Wellnhofer).
* Support CR and CRLF line endings (Ben Trask).
* Added test for different line endings to `api_test`.
* Allow NULL value in string setters (Nick Wellnhofer). (NULL
produces a 0-length string value.) Internally, URL and
title are now stored as `cmark_chunk` rather than `char *`.
* Fixed memory leak in `cmark_consolidate_text_nodes` (32).
* Fixed `is_autolink` in the CommonMark renderer (50). Previously *any*
link with an absolute URL was treated as an autolink.
* Cope with broken `snprintf` on Windows (Nick Wellnhofer). On Windows,
`snprintf` returns -1 if the output was truncated. Fall back to
Windows-specific `_scprintf`.
* Switched length parameter on `cmark_markdown_to_html`,
`cmark_parser_feed`, and `cmark_parse_document` from `int`
to `size_t` (53, Nick Wellnhofer).
* Use a custom type `bufsize_t` for all string sizes and indices.
This allows to switch to 64-bit string buffers by changing a single
typedef and a macro definition (Nick Wellnhofer).
* Hardened the `strbuf` code, checking for integer overflows and
adding range checks (Nick Wellnhofer).
* Removed unused function `cmark_strbuf_attach` (Nick Wellnhofer).
* Fixed all implicit 64-bit to 32-bit conversions that
`-Wshorten-64-to-32` warns about (Nick Wellnhofer).
* Added helper function `cmark_strbuf_safe_strlen` that converts
from `size_t` to `bufsize_t` and throws an error in case of
an overflow (Nick Wellnhofer).
* Abort on `strbuf` out of memory errors (Nick Wellnhofer).
Previously such errors were not being trapped. This involves
some internal changes to the `buffer` library that do not affect
the API.
* Factored out `S_find_first_nonspace` in `S_proces_line`.
Added fields `offset`, `first_nonspace`, `indent`, and `blank`
to `cmark_parser` struct. This just removes some repetition.
* Added Racket Racket (5.3+) wrapper (Eli Barzilay).
* Removed `-pg` from Debug build flags (47).
* Added Ubsan build target, to check for undefined behavior.
* Improved `make leakcheck`. We now return an error status if anything
in the loop fails. We now check `--smart` and `--normalize` options.
* Removed `wrapper3.py`, made `wrapper.py` work with python 2 and 3.
Also improved the wrapper to work with Windows, and to use smart
punctuation (as an example).
* In `wrapper.rb`, added argument for options.
* Revised luajit wrapper.
* Added build status badges to README.md.
* Added links to go, perl, ruby, R, and Haskell bindings to README.md.

* Fixed `_` emphasis parsing to conform to spec (jgm/CommonMark317).
* Updated `spec.txt`.
* Compile static library with `-DCMARK_STATIC_DEFINE` (Nick Wellnhofer).
* Suppress warnings about Windows runtime library files (Nick Wellnhofer).
Visual Studio Express editions do not include the redistributable files.
Set `CMAKE_INSTALL_SYSTEM_RUNTIME_LIBS_NO_WARNINGS` to suppress warnings.
* Added appyeyor: Windows continuous integration (`appveyor.yml`).
* Use `os.path.join` in `test/cmark.py` for proper cross-platform paths.
* Fixed `Makefile.nmake`.
* Improved `make afl`: added `test/afl_dictionary`, increased timeout
for hangs.
* Improved README with a description of the library's strengths.
* Pass-through Unicode non-characters (Nick Wellnhofer).
Despite their name, Unicode non-characters are valid code points. They
should be passed through by a library like libcmark.
* Check return status of `utf8proc_iterate` (27).

* Include patch level in soname (Nick Wellnhofer). Minor version is
tied to spec version, so this allows breaking the ABI between spec
releases.
* Install compiler-provided system runtime libraries (Changjiang Yang).
* Use `strbuf_printf` instead of `snprintf`. `snprintf` is not
available on some platforms (Visual Studio 2013 and earlier).
* Fixed memory access bug: "invalid read of size 1" on input `[link](<>)`.