Before this change, the Rust `unstable-book` is 88MiB.
With this change, it becomes 15MiB. Other pages might not be
as extreme, but it's expected to help any book like this.
This change is so drastic because, if every chapter has a link to
every other chapter, the result is *O*(n<sup>2</sup>) text output.
Above mentioned function copies files (recursively) from a source to a
destination directory. For that, file/directory paths have to be created
repeatedly. This allocates as directory and file names are concatenated
into an owning path structure.
The number of allocations can be reduced by creating file/directory
paths only once and borrowing them instead of cloning/recreating them.
In bigger projects, this reduces execution time noticeably. Please note
that file system operations are dominant from performance POV.
on rust reference book this reduces total allocs from 490mb to 474mb:
==23272== Total: 490,538,699 bytes in 1,760,117 blocks
==23272== At t-gmax: 13,872,954 bytes in 4,655 blocks
==23272== At t-end: 488,516 bytes in 884 blocks
==23272== Reads: 830,509,060 bytes
==23272== Writes: 522,290,614 bytes
to
==40876== Total: 474,156,323 bytes in 1,521,025 blocks
==40876== At t-gmax: 13,872,954 bytes in 4,655 blocks
==40876== At t-end: 488,516 bytes in 884 blocks
==40876== Reads: 820,933,434 bytes
==40876== Writes: 514,838,350 bytes
Currently, the output from `rustdoc --test` is not colored because
`rustdoc`'s stdout is not a tty. The output of a failed `rustdoc` run is
sent to `mdbook`'s stderr via the `error!()` macro. This commit checks
if stderr is a tty using the standard `.is_terminal()` and if so, passes
`--color always` to `rustdoc`.
The test output from `rustdoc` includes the full path that `rustdoc` was
called with. This obscures the path of the file with the error. E.g.,
```
---- /var/folders/9v/90bm7kb10fx3_bprxltb3t1r0000gn/T/mdbook-tnGJxp/lab0/index.md - Lab_0__Getting_Started (line 3) stdout ----
error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `code`
--> /var/folders/9v/90bm7kb10fx3_bprxltb3t1r0000gn/T/mdbook-tnGJxp/lab0/index.md:4:6
|
3 | this code has a bug
| ^^^^ expected one of 8 possible tokens
error: aborting due to previous error
```
This commit runs `rustdoc` in the temp directory and replaces any
relative library paths with absolute library paths. This leads to
simpler error messages. The one above becomes
```
---- lab0/index.md - Lab_0__Getting_Started (line 3) stdout ----
error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `code`
--> lab0/index.md:4:6
|
3 | this code has a bug
| ^^^^ expected one of 8 possible tokens
error: aborting due to previous error
```
(with colors, of course).
Nim is a systems programming language (included in the highlight.js
`system` group), and we're quite happily using `mdBook` in several of
our documentation projects starting with our [style
guide](https://status-im.github.io/nim-style-guide/).
While we can maintain our own highlight.js, including `Nim` in the
default distribution would allow us to promote more mdBook usage in the
Nim community at the cost of a ~2kb increase in the `highlight.js` size.
