The Gitiles source browser
automatically renders *.md Markdown files into HTML for simplified
documentation.
[TOC]
Access controls for documentation is identical to source code.
Documentation stored with source files shares the same permissions. Documentation stored in a separate Git repository can use different access controls. If Gerrit Code Review is being used, branch level read permissions can be used to grant or restrict access to any documentation branches.
Files named README.md are automatically displayed below the file's
directory listing. For the top level directory this mirrors the
standard GitHub presentation.
*** promo README.md files are meant to provide orientation for developers browsing the repository, especially first-time users.
We recommend that Git repositories have an up-to-date top-level
README.md file.
Gitiles supports the core Markdown syntax described in Markdown Basics. Additional extensions are supported to more closely match GitHub Flavored Markdown and simplify documentation writing.
Paragraphs are one or more lines of consecutive text, followed by one or more blank lines. Line breaks within a paragraph are ignored by the parser, allowing authors to line-wrap text at any comfortable column width.
Documentation writing can be fun and profitable
by helping users to learn and solve problems.
After documentation is written, it needs to be published on the
web where it can be easily accessed for reading.
Headings can be indicated by starting the line with one or more #
marks. The number of # used determines the depth of the heading in
the document outline. Headings 1 through 6 (######) are supported.
# A level one (H1) heading
## A level two (H2) heading
### A level three (H3) heading
Headings can also use the less popular two line ====== and ------
forms to create H1 and H2 level headers:
A first level header
====================
A second level header
---------------------
This form is discouraged as maintaining the length of the === or
--- lines to match the preceding line can be tedious work that is
unnecessary with the # headers.
A bullet list:
* Fruit
* Orange
* Pear
* Cake
will render into HTML as:
- Fruit
- Orange
- Pear
- Cake
The second level items (above Orange, Pear) must be indented with more spaces than the item they are nested under. Above 2 spaces were used. Additionally, the entire list must be preceded and followed by a blank line.
A numbered list:
1. Fruit
1. Orange
2. Pear
5. Cake
will render into HTML as:
- Fruit
- Orange
- Pear
- Cake
List items will be renumbered sequentially by the browser, which is
why 5 above displays as 2. Even with this feature it is a good
idea to maintain list item numbers in the source Markdown to simplify
reading the source file.
Like bullet lists, numbered lists can be nested by using more leading space than the prior list item.
Paragraphs can be properly nested within lists by indenting with at least 2 leading spaces:
1. Fruit
In botany, a fruit is the seed-bearing structure in flowering
plants.
In common language usage, "fruit" normally means the fleshy
seed-associated structures of a plant that are sweet or sour, and
edible in the raw state, such as apples, bananas, grapes, lemons,
oranges, and strawberries.
2. Cake
The cake is a lie.
Requires markdown.tables to be true (default).
Simple tables are supported with column alignment. The first line is the header row and subsequent lines are data rows:
| Food | Calories | Tasty? |
|-------|---------:|:------:|
| Apple | 95 | Yes |
| Pear | 102 | Yes |
| Hay | 977 | |
will render as:
| Food | Calories | Tasty? |
|---|---|---|
| Apple | 95 | Yes |
| Pear | 102 | Yes |
| Hay | 977 |
Placing : in the separator line indicates how the column should be
aligned. A colon on the left side is a left-aligned column; a
colon on the right-most side is right-aligned; a colon on both
sides is center-aligned. If no alignment is specified, the column
is aligned with the default for HTML <td> tags (left-aligned by
default unless overridden by css).
Empty table cells are indicated by whitespace between the column
dividers (| |) while multiple column cells omit the whitespace.
Emphasize paragraph text with italic and bold styles. Either _
or * can be used for italic (1 character) and bold text (2
characters). This allows styles to be mixed within a statement:
Emphasize paragraph text with *italic* and **bold** text.
**It is _strongly_ encouraged to review documentation for typos.**
It is strongly encouraged to review documentation for typos.
Emphasis within_words_is_ignored which helps write technical
documentation. Literal *bold* can be forced by prefixing the
opening * with \ such as \*bold*.
Requires markdown.strikethrough to be true (default).
Text can be struck out within a paragraph:
Text can be ~~struck out~~ within a paragraph.
Note two tildes are required (~~) on either side of the struck out
section of text.
Blockquoted text can be used to stand off text obtained from another source:
Sir Winston Churchill once said:
> A lie gets halfway around the world before the truth has a
> chance to get its pants on.
renders as:
Sir Winston Churchill once said:
A lie gets halfway around the world before the truth has a chance to get its pants on.
Use backticks to markup inline code within a paragraph:
Use `backticks` to markup inline code within a paragraph.
Create a fenced code block using three backticks before and after a block of code, preceeded and followed by blank lines:
This is a simple hello world program in C:
``` c
#include <stdio.h>
int main() {
printf("Hello, World.\n");
return 0;
}
```
To compile it use `gcc hello.c`.
Text within a fenced code block is taken verbatim and is not processed for Markdown markup.
Syntax highlighting can optionally be enabled for common languages by adding the language name in lowercase on the opening line. Supported languages include:
|||---||| 2,2,2,2,4
- bash, sh
- lua
- perl
- python, py
- ruby
- tcl
- css
- dart
- html
- javascript, js
- json
- basic, vb
- c
- cpp (C++)
- go
- java
- pascal
- scala
- tex, latex
- wiki
- xml
- xquery
- xsl
- yaml
If markdown.ghthematicbreak is true, a horizontal rule can be
inserted using GitHub style -- surrounded by blank lines.
Alternatively repeating - or * and space on a line will also
create a horizontal rule:
---
- - - -
* * * *
Wrap text in [brackets] and the link destination in parens
(http://...) such as:
Visit [this site](http://example.com/) for more examples.
Links can also use references to obtain URLs from elsewhere in the same document. This style can be useful if the same URL needs to be mentioned multiple times, is too long to cleanly place within text, or the link is within a table cell:
Search for [markdown style][1] examples.
[1]: https://www.google.com/?gws_rd=ssl#q=markdown+style+guide
References can be simplified if the text alone is sufficient:
Visit [Google] to search the web.
[Google]: https://www.google.com/
Automatic hyperlinking can be used where the link text should obviously also be the URL:
Use https://www.google.com/ to search the web.
Well formed URLs beginning with https://, http://, and mailto:
are used as written for the link's destination. Malformed URLs may be
replaced with about:invalid#zSoyz to prevent browser evaluation of dangerous
content.
HTML escaping of URL characters such as & is handled internally by
the parser/formatter. Documentation writers should insert the URL
literally and allow the parser and formatter to make it HTML safe.
Relative links such as ../src/api.md are resolved relative to the
current markdown's file path within the Git repository. Absolute
links such as /src/api.md are resolved relative to the top of the
enclosing Git repository, but within the same branch or Git commit.
Links may point to any file in the repository. A link to a *.md
file will present the rendered markdown, while a link to a source file
will display the syntax highlighted source.
Explicit anchors can be inserted anywhere in the document using
<a name="tag"></a>, or {#tag} if markdown.namedanchor is true.
Implicit anchors are automatically created for each
heading. For example ## Section 1 will have
the anchor Section-1.
*** note Anchor generation
- letters and digits, after removing accents (á → a)
- spaces are replaced with hyphens (
-) - other characters are replaced with underscores (
_) - runs of hyphens and underscores are collapsed
If a document contains the same named subsection under different
parents the parent anchor will prefix the subsections to
disambiguate. For example the following document will have anchors
Running-Format and Coding-Format and Libraries as that subsection
is unique:
## Running
### Format
## Coding
### Format
### Libraries
When placed in a section header the explicit anchor will override
the automatic anchor. The following are identical and associate
the anchor live-examples with the section header instead of the
automaticly generated name Examples.
## Examples {#live-examples}
## Examples <a name="live-examples"></a>
Similar to links but begin with ! to denote an image reference:
For images the text in brackets will be included as the alt text for screen readers.
Well formed image URLs beginning with https:// and http:// will be
used as written for the <img src="..."> attribute. Malformed URLs
will be replaced with a broken data: reference to prevent browsers
from trying to load a bad destination.
Relative and absolute links to image files within the Git repository
(such as ../images/banner.png) are resolved during rendering by
inserting the base64 encoding of the image using a data: URI. Only
PNG (*.png), JPEG (*.jpg or *.jpeg) and GIF (*.gif) image
formats are supported when referenced from the Git repository.
Unsupported extensions or files larger than image size limit (default 256K) will display a broken image.
*** note Inline image caching
Gitiles allows browsers to locally cache rendered markdown pages.
Cache invalidation is triggered by the markdown file being modified
and having a different SHA-1 in Git. Inlined images may need a
documentation file update to be refreshed when viewed through unstable
URLs like /docs/+/master/index.md.
Most HTML tags are not supported. HTML will be dropped on the floor by the parser with no warnings, and no output from that section of the document.
If markdown.safehtml is true there are small exceptions for <br>,
<hr>, <a name> and <iframe> elements, see named anchor
and HTML IFrame.
Gitiles includes additional extensions to the Markdown language that make documentation writing for the web easier without using raw HTML.
Requires markdown.toc to be true.
Place [TOC] surrounded by blank lines to insert a generated
table of contents extracted from the H1, H2, and H3 headers
used within the document:
# Title
[TOC]
## Section 1
Blah blah...
## Section 2
Go on...
H1 headers are omitted from the table of contents if there is only one level one header present. This allows H1 to be used as the document title without creating an unnecessary entry in the table of contents.
Anchors are automatically extracted from the headers, see named anchors.
Requires markdown.blocknote to be true.
Similar to fenced code blocks these blocks start and end with ***,
are surrounded by blank lines, and include the type of block on the
opening line.
*** note
**Warning:** watch out for nested formatting.
***
*** note Warning: watch out for nested formatting.
*** aside
An aside can stand off less interesting text.
***
*** aside An aside can stand off less interesting text.
*** promo
Promotions can raise awareness of an important concept.
***
*** promo Promotions can raise awareness of an important concept.
Requires markdown.multicolumn to be true.
Gitiles markdown includes support for up to 12 columns of text across the width of the page. By default space is divided equally between the columns.
|||---|||
can save space.
the page layout.
*** promo
trendy.
|||---|||
A column layout is denoted by a block starting and ending with the
sequence |||---|||. Within the layout a new column is started for
each header or note/promo/aside block and all text and formatting flow
into that column until a new column is started.
|||---|||
#### Columns
can save space.
#### Prettify
the page layout.
*** promo
#### Can be
trendy.
***
|||---|||
Column spans can be specified on the first line as a comma separated list. In the example below the first column is 4 wide or 4/12ths of the page width, the second is 2 wide (or 2/12ths) and the final column is 6 wide (6/12ths or 50%) of the page.
|||---||| 4,2,6
An empty column can be inserted by prefixing its width with :,
for example shifting content onto the right by padding 6 columns
on the left:
|||---||| :6,3
#### Right
|||---|||
renders as:
|||---||| :6,3
|||---|||
Requires markdown.safehtml to be true (default).
Although HTML is stripped the parser has special support for a limited
subset of <iframe> elements:
<iframe src="https://example.com/embed" height="200px" width="400px"></iframe>
The parser allows whitespace including newlines between attributes, but strictly limits the supported attribute set to:
src
: An https:// or http:// URL of the page to embed inside of an
iframe at this position in the document. Malformed URLs will cause
the iframe to be silently dropped. (required)
height
: CSS pixel height such as 250px defining the amount of vertical
space to give to the embedded content. Only px units are supported;
a malformed dimension will drop the iframe. (required)
width
: CSS pixel width such as 250px or a precentage such as 80%
defining the amount of horizontal space to give to the embedded
content. Only px units or % are supported; a malformed dimension
will drop the iframe. (required)
frameborder
: By default a border is drawn around the iframe by the browser. The
border can be hidden by adding frameborder="0" to the iframe tag.
(optional)
Embedded source URLs must also be whitelisted by the Gitiles
markdown.allowiframe configuration
variable.
Gitiles includes additional support to create functional documentation sites served directly from Git repositories.
A top level navigation bar is automatically included on all pages if
there is a navbar.md file present in the top of the repository.
This file should be a simple bulleted list of links to include in the
navigation bar.
* [Home](/index.md)
* [Markdown](/docs/markdown.md)
* [Configuration](/docs/configuration.md)
Links are resolved relative to the current page, not navbar.md.
Links to other files within the repository should use absolute paths
to ensure they are resolved correctly from any Markdown file within
the repository.
A site-wide banner is displayed on all Markdown pages if navbar.md
includes an H1 header. The text of the header is displayed on the
left side of the banner.
# Gitiles
* [Home](/index.md)
An optional logo image is displayed in the banner to the left of the
site title if a [logo] reference exists in navbar.md. This image
should be no taller than 45 px.
# Gitiles
[logo]: /images/site_logo.png
See images above for acceptable URLs and how repository relative paths are handled by inline data URIs.
Both the site logo (if present) and site title are wrapped in a link
if the [home] reference is declared in navbar.md. This is
typically also used in the outline for the navigation bar:
# Gitiles
* [Home][home]
* [Markdown](/docs/markdown.md)
[home]: /index.md
Titles for pages are extracted from the first H1 heading appearing in the document. This is traditionally placed on the first line of the markdown file, e.g.:
# Markdown
The title is included in the HTML <title> element and also in the
right side of the banner if navbar.md defines a
site title.
The gitiles.config file supporting the site contains several
configuration options that impact markdown rendering. Refer to the
configuration documentation for details.