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diff --git a/vendor/github.com/russross/blackfriday/README.md b/vendor/github.com/russross/blackfriday/README.md new file mode 100644 index 00000000..a6c94b79 --- /dev/null +++ b/vendor/github.com/russross/blackfriday/README.md @@ -0,0 +1,363 @@ +Blackfriday +[![Build Status][BuildSVG]][BuildURL] +[![Godoc][GodocV2SVG]][GodocV2URL] +=========== + +Blackfriday is a [Markdown][1] processor implemented in [Go][2]. It +is paranoid about its input (so you can safely feed it user-supplied +data), it is fast, it supports common extensions (tables, smart +punctuation substitutions, etc.), and it is safe for all utf-8 +(unicode) input. + +HTML output is currently supported, along with Smartypants +extensions. + +It started as a translation from C of [Sundown][3]. + + +Installation +------------ + +Blackfriday is compatible with any modern Go release. With Go and git installed: + + go get -u gopkg.in/russross/blackfriday.v2 + +will download, compile, and install the package into your `$GOPATH` directory +hierarchy. + + +Versions +-------- + +Currently maintained and recommended version of Blackfriday is `v2`. It's being +developed on its own branch: https://github.com/russross/blackfriday/tree/v2 and the +documentation is available at +https://godoc.org/gopkg.in/russross/blackfriday.v2. + +It is `go get`-able via via [gopkg.in][6] at `gopkg.in/russross/blackfriday.v2`, +but we highly recommend using package management tool like [dep][7] or +[Glide][8] and make use of semantic versioning. With package management you +should import `github.com/russross/blackfriday` and specify that you're using +version 2.0.0. + +Version 2 offers a number of improvements over v1: + +* Cleaned up API +* A separate call to [`Parse`][4], which produces an abstract syntax tree for + the document +* Latest bug fixes +* Flexibility to easily add your own rendering extensions + +Potential drawbacks: + +* Our benchmarks show v2 to be slightly slower than v1. Currently in the + ballpark of around 15%. +* API breakage. If you can't afford modifying your code to adhere to the new API + and don't care too much about the new features, v2 is probably not for you. +* Several bug fixes are trailing behind and still need to be forward-ported to + v2. See issue [#348](https://github.com/russross/blackfriday/issues/348) for + tracking. + +If you are still interested in the legacy `v1`, you can import it from +`github.com/russross/blackfriday`. Documentation for the legacy v1 can be found +here: https://godoc.org/github.com/russross/blackfriday + +### Known issue with `dep` + +There is a known problem with using Blackfriday v1 _transitively_ and `dep`. +Currently `dep` prioritizes semver versions over anything else, and picks the +latest one, plus it does not apply a `[[constraint]]` specifier to transitively +pulled in packages. So if you're using something that uses Blackfriday v1, but +that something does not use `dep` yet, you will get Blackfriday v2 pulled in and +your first dependency will fail to build. + +There are couple of fixes for it, documented here: +https://github.com/golang/dep/blob/master/docs/FAQ.md#how-do-i-constrain-a-transitive-dependencys-version + +Meanwhile, `dep` team is working on a more general solution to the constraints +on transitive dependencies problem: https://github.com/golang/dep/issues/1124. + + +Usage +----- + +### v1 + +For basic usage, it is as simple as getting your input into a byte +slice and calling: + + output := blackfriday.MarkdownBasic(input) + +This renders it with no extensions enabled. To get a more useful +feature set, use this instead: + + output := blackfriday.MarkdownCommon(input) + +### v2 + +For the most sensible markdown processing, it is as simple as getting your input +into a byte slice and calling: + +```go +output := blackfriday.Run(input) +``` + +Your input will be parsed and the output rendered with a set of most popular +extensions enabled. If you want the most basic feature set, corresponding with +the bare Markdown specification, use: + +```go +output := blackfriday.Run(input, blackfriday.WithNoExtensions()) +``` + +### Sanitize untrusted content + +Blackfriday itself does nothing to protect against malicious content. If you are +dealing with user-supplied markdown, we recommend running Blackfriday's output +through HTML sanitizer such as [Bluemonday][5]. + +Here's an example of simple usage of Blackfriday together with Bluemonday: + +```go +import ( + "github.com/microcosm-cc/bluemonday" + "gopkg.in/russross/blackfriday.v2" +) + +// ... +unsafe := blackfriday.Run(input) +html := bluemonday.UGCPolicy().SanitizeBytes(unsafe) +``` + +### Custom options, v1 + +If you want to customize the set of options, first get a renderer +(currently only the HTML output engine), then use it to +call the more general `Markdown` function. For examples, see the +implementations of `MarkdownBasic` and `MarkdownCommon` in +`markdown.go`. + +### Custom options, v2 + +If you want to customize the set of options, use `blackfriday.WithExtensions`, +`blackfriday.WithRenderer` and `blackfriday.WithRefOverride`. + +### `blackfriday-tool` + +You can also check out `blackfriday-tool` for a more complete example +of how to use it. Download and install it using: + + go get github.com/russross/blackfriday-tool + +This is a simple command-line tool that allows you to process a +markdown file using a standalone program. You can also browse the +source directly on github if you are just looking for some example +code: + +* <http://github.com/russross/blackfriday-tool> + +Note that if you have not already done so, installing +`blackfriday-tool` will be sufficient to download and install +blackfriday in addition to the tool itself. The tool binary will be +installed in `$GOPATH/bin`. This is a statically-linked binary that +can be copied to wherever you need it without worrying about +dependencies and library versions. + +### Sanitized anchor names + +Blackfriday includes an algorithm for creating sanitized anchor names +corresponding to a given input text. This algorithm is used to create +anchors for headings when `EXTENSION_AUTO_HEADER_IDS` is enabled. The +algorithm has a specification, so that other packages can create +compatible anchor names and links to those anchors. + +The specification is located at https://godoc.org/github.com/russross/blackfriday#hdr-Sanitized_Anchor_Names. + +[`SanitizedAnchorName`](https://godoc.org/github.com/russross/blackfriday#SanitizedAnchorName) exposes this functionality, and can be used to +create compatible links to the anchor names generated by blackfriday. +This algorithm is also implemented in a small standalone package at +[`github.com/shurcooL/sanitized_anchor_name`](https://godoc.org/github.com/shurcooL/sanitized_anchor_name). It can be useful for clients +that want a small package and don't need full functionality of blackfriday. + + +Features +-------- + +All features of Sundown are supported, including: + +* **Compatibility**. The Markdown v1.0.3 test suite passes with + the `--tidy` option. Without `--tidy`, the differences are + mostly in whitespace and entity escaping, where blackfriday is + more consistent and cleaner. + +* **Common extensions**, including table support, fenced code + blocks, autolinks, strikethroughs, non-strict emphasis, etc. + +* **Safety**. Blackfriday is paranoid when parsing, making it safe + to feed untrusted user input without fear of bad things + happening. The test suite stress tests this and there are no + known inputs that make it crash. If you find one, please let me + know and send me the input that does it. + + NOTE: "safety" in this context means *runtime safety only*. In order to + protect yourself against JavaScript injection in untrusted content, see + [this example](https://github.com/russross/blackfriday#sanitize-untrusted-content). + +* **Fast processing**. It is fast enough to render on-demand in + most web applications without having to cache the output. + +* **Thread safety**. You can run multiple parsers in different + goroutines without ill effect. There is no dependence on global + shared state. + +* **Minimal dependencies**. Blackfriday only depends on standard + library packages in Go. The source code is pretty + self-contained, so it is easy to add to any project, including + Google App Engine projects. + +* **Standards compliant**. Output successfully validates using the + W3C validation tool for HTML 4.01 and XHTML 1.0 Transitional. + + +Extensions +---------- + +In addition to the standard markdown syntax, this package +implements the following extensions: + +* **Intra-word emphasis supression**. The `_` character is + commonly used inside words when discussing code, so having + markdown interpret it as an emphasis command is usually the + wrong thing. Blackfriday lets you treat all emphasis markers as + normal characters when they occur inside a word. + +* **Tables**. Tables can be created by drawing them in the input + using a simple syntax: + + ``` + Name | Age + --------|------ + Bob | 27 + Alice | 23 + ``` + +* **Fenced code blocks**. In addition to the normal 4-space + indentation to mark code blocks, you can explicitly mark them + and supply a language (to make syntax highlighting simple). Just + mark it like this: + + ``` go + func getTrue() bool { + return true + } + ``` + + You can use 3 or more backticks to mark the beginning of the + block, and the same number to mark the end of the block. + + To preserve classes of fenced code blocks while using the bluemonday + HTML sanitizer, use the following policy: + + ``` go + p := bluemonday.UGCPolicy() + p.AllowAttrs("class").Matching(regexp.MustCompile("^language-[a-zA-Z0-9]+$")).OnElements("code") + html := p.SanitizeBytes(unsafe) + ``` + +* **Definition lists**. A simple definition list is made of a single-line + term followed by a colon and the definition for that term. + + Cat + : Fluffy animal everyone likes + + Internet + : Vector of transmission for pictures of cats + + Terms must be separated from the previous definition by a blank line. + +* **Footnotes**. A marker in the text that will become a superscript number; + a footnote definition that will be placed in a list of footnotes at the + end of the document. A footnote looks like this: + + This is a footnote.[^1] + + [^1]: the footnote text. + +* **Autolinking**. Blackfriday can find URLs that have not been + explicitly marked as links and turn them into links. + +* **Strikethrough**. Use two tildes (`~~`) to mark text that + should be crossed out. + +* **Hard line breaks**. With this extension enabled (it is off by + default in the `MarkdownBasic` and `MarkdownCommon` convenience + functions), newlines in the input translate into line breaks in + the output. + +* **Smart quotes**. Smartypants-style punctuation substitution is + supported, turning normal double- and single-quote marks into + curly quotes, etc. + +* **LaTeX-style dash parsing** is an additional option, where `--` + is translated into `–`, and `---` is translated into + `—`. This differs from most smartypants processors, which + turn a single hyphen into an ndash and a double hyphen into an + mdash. + +* **Smart fractions**, where anything that looks like a fraction + is translated into suitable HTML (instead of just a few special + cases like most smartypant processors). For example, `4/5` + becomes `<sup>4</sup>⁄<sub>5</sub>`, which renders as + <sup>4</sup>⁄<sub>5</sub>. + + +Other renderers +--------------- + +Blackfriday is structured to allow alternative rendering engines. Here +are a few of note: + +* [github_flavored_markdown](https://godoc.org/github.com/shurcooL/github_flavored_markdown): + provides a GitHub Flavored Markdown renderer with fenced code block + highlighting, clickable heading anchor links. + + It's not customizable, and its goal is to produce HTML output + equivalent to the [GitHub Markdown API endpoint](https://developer.github.com/v3/markdown/#render-a-markdown-document-in-raw-mode), + except the rendering is performed locally. + +* [markdownfmt](https://github.com/shurcooL/markdownfmt): like gofmt, + but for markdown. + +* [LaTeX output](https://bitbucket.org/ambrevar/blackfriday-latex): + renders output as LaTeX. + + +TODO +---- + +* More unit testing +* Improve Unicode support. It does not understand all Unicode + rules (about what constitutes a letter, a punctuation symbol, + etc.), so it may fail to detect word boundaries correctly in + some instances. It is safe on all UTF-8 input. + + +License +------- + +[Blackfriday is distributed under the Simplified BSD License](LICENSE.txt) + + + [1]: https://daringfireball.net/projects/markdown/ "Markdown" + [2]: https://golang.org/ "Go Language" + [3]: https://github.com/vmg/sundown "Sundown" + [4]: https://godoc.org/gopkg.in/russross/blackfriday.v2#Parse "Parse func" + [5]: https://github.com/microcosm-cc/bluemonday "Bluemonday" + [6]: https://labix.org/gopkg.in "gopkg.in" + [7]: https://github.com/golang/dep/ "dep" + [8]: https://github.com/Masterminds/glide "Glide" + + [BuildSVG]: https://travis-ci.org/russross/blackfriday.svg?branch=master + [BuildURL]: https://travis-ci.org/russross/blackfriday + [GodocV2SVG]: https://godoc.org/gopkg.in/russross/blackfriday.v2?status.svg + [GodocV2URL]: https://godoc.org/gopkg.in/russross/blackfriday.v2 |