This avoids having to execute these expensive operations for sites not using these values.
This commit sums up a set of wordcounting and autosummary related performance improvements.
The effect of these kind of depends on what features your site use, but a benchmark from 4 Hugo sites in the wild shows promise:
```
benchmark old ns/op new ns/op delta
BenchmarkHugo-4 21293005843 20032857342 -5.92%
benchmark old allocs new allocs delta
BenchmarkHugo-4 65290922 65186032 -0.16%
benchmark old bytes new bytes delta
BenchmarkHugo-4 9771213416 9681866464 -0.91%
```
Closes#2378
It is obviously more efficient when we do not care about the actual words.
```
BenchmarkTotalWords-4 100000 18795 ns/op 0 B/op 0 allocs/op
BenchmarkTotalWordsOld-4 30000 46751 ns/op 6400 B/op 1 allocs/op
```
For people using autogenerated summaries, this is one of the hot spots in the memory department.
We don't need to split al the content into words to do proper summary truncation.
This is obviously more effective:
```
BenchmarkTestTruncateWordsToWholeSentence-4 300000 4720 ns/op 0 B/op 0 allocs/op
BenchmarkTestTruncateWordsToWholeSentenceOld-4 100000 17699 ns/op 3072 B/op 3 allocs/op
```
Hugo 0.16 announced support for symbolic links for the root folders, /content, /static etc., but this got broken pretty fast.
The main problem this commit tries to solve is the matching of file change events to "what changed".
An example:
ContentDir: /mysites/site/content where /mysites/site/content is a symlink to /mycontent
/mycontent:
/mypost1.md
/post/mypost2.md
* A change to mypost1.md (on OS X) will trigger a file change event with name "/mycontent/mypost1.md"
* A change to mypost2.md gives event with name "/mysites/site/content/mypost2.md"
The first change will not trigger a correct update of Hugo before this commit. This commit fixes this by doing a two-step check:
1. Check if "/mysites/site/content/mypost2.md" is within /mysites/site/content
2. Check if "/mysites/site/content/mypost2.md" is within the real path that /mysites/site/content points to
Fixes#2265Closes#2273
Mitchell Cohen