Suggestion: let hexo support incremental build.

[ahuigo]

Environment Info

Node version(node -v):

hexo-cli: 1.1.0
os: Darwin 15.6.0 darwin x64
node: 10.0.0

Your site _config.yml (Optional):
https://github.com/ahuigo/hexo-theme-next/blob/master/_config.yml

Your theme _config.yml (Optional):
https://github.com/ahuigo/hexo-conf/blob/master/_config.yml

Hexo and Plugin version(npm ls --depth 0):

├─┬ UNMET DEPENDENCY hexo@3.7.1
│ ├── abbrev@1.1.1
│ ├── archy@1.0.0
│ ├── bluebird@3.5.2
│ ├── chalk@2.4.1
│ ├── cheerio@0.22.0
│ ├── hexo-cli@1.1.0
│ ├── hexo-front-matter@0.2.3
│ ├── hexo-fs@0.2.3
│ ├── hexo-i18n@0.2.1
│ ├── hexo-log@0.2.0
│ ├── hexo-util@0.6.3
│ ├── js-yaml@3.12.0
│ ├── lodash@4.17.11
│ ├── minimatch@3.0.4
│ ├── moment@2.22.2
│ ├── moment-timezone@0.5.21
│ ├── nunjucks@3.1.3
│ ├── pretty-hrtime@1.0.3
│ ├── resolve@1.8.1
│ ├── strip-ansi@4.0.0
│ ├── strip-indent@2.0.0
│ ├── swig-extras@0.0.1
│ ├── swig-templates@2.0.3
│ ├── text-table@0.2.0
│ ├── tildify@1.2.0
│ ├── titlecase@1.1.2
│ └── warehouse@2.2.0
├── UNMET DEPENDENCY hexo-deployer-git@^0.3.1
├── UNMET DEPENDENCY hexo-directory-category@^1.0.5
├─┬ UNMET DEPENDENCY hexo-generator-archive@0.1.5
│ ├── hexo-pagination@0.0.2
│ └── object-assign@2.1.1
├─┬ UNMET DEPENDENCY hexo-generator-baidu-sitemap@0.1.5
│ ├── ejs@2.6.1
│ ├── hexo@3.7.1
│ └── utils-merge@1.0.1
├─┬ UNMET DEPENDENCY hexo-generator-category@0.1.3
│ ├── hexo-pagination@0.0.2
│ └── object-assign@2.1.1
├─┬ UNMET DEPENDENCY hexo-generator-feed@1.2.2
│ ├── nunjucks@3.1.3
│ └── object-assign@4.1.1
├─┬ UNMET DEPENDENCY hexo-generator-index@0.2.1
│ ├── hexo-pagination@0.0.2
│ └── object-assign@4.1.1
├─┬ UNMET DEPENDENCY hexo-generator-tag@0.2.0
│ ├── hexo-pagination@0.0.2
│ └── object-assign@4.1.1
├─┬ UNMET DEPENDENCY hexo-renderer-ejs@0.3.1
│ ├── ejs@2.6.1
│ └── object-assign@4.1.1
├─┬ UNMET DEPENDENCY hexo-renderer-markdown-it-plus@1.0.3
│ ├── @iktakahiro/markdown-it-katex@3.0.4
│ ├── clone@2.1.2
│ ├── highlight.js@9.12.0
│ ├── markdown-it@8.4.2
│ ├── markdown-it-abbr@1.0.4
│ ├── markdown-it-deflist@2.0.3
│ ├── markdown-it-emoji@1.4.0
│ ├── markdown-it-footnote@3.0.1
│ ├── markdown-it-ins@2.0.0
│ ├── markdown-it-mark@2.0.0
│ ├── markdown-it-sub@1.0.0
│ ├── markdown-it-sup@1.0.0
│ ├── markdown-it-toc@1.1.0
│ └── uslug@1.0.4
├─┬ UNMET DEPENDENCY hexo-renderer-stylus@0.3.3
│ ├── nib@1.1.2
│ └── stylus@0.54.5
└─┬ UNMET DEPENDENCY hexo-server@0.3.3
  ├── bluebird@3.5.2
  ├── chalk@1.1.3
  ├── compression@1.7.3
  ├── connect@3.6.6
  ├── mime@1.6.0
  ├── morgan@1.9.1
  ├── object-assign@4.1.1
  ├── opn@5.4.0
  └── serve-static@1.13.2

For Bug

Hexo does not support Incremental Build.

I found that hexo will still render files even there is no file modified.
It eventually caused the slow hexo build.

➜ blog2$ git:(master) ✗hexo g
INFO  Start processing
INFO  Files loaded in 3.29 s
INFO  0 files generated in 1.38 min

$ hexo --debug g
......
07:39:30.641 DEBUG Rendering post: c/ops-systemd-log/index.html
07:39:30.907 DEBUG Rendering post: c/ops-fabric/index.html
07:39:31.140 DEBUG Rendering post: c/ops-dd/index.html

For feature request

Let hexo support incremental build.