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+# cquery
+
+cquery is a low-latency language server for C++. It is extremely scalable and
+has been designed for and tested on large code bases like
+[Chromium](https://chromium.googlesource.com/chromium/src/). It's primary goal
+is to make working on large code bases much faster by providing accurate and
+fast semantic analysis.
+
+![](images/demo.png)
+
+There are rough edges (especially when editing), but it is already possible to
+be productive with cquery. Here's a list of implemented features:
+  * code completion
+  * references
+  * type hierarchy
+  * calls to functions, calls to base and derived functions
+  * rename
+  * goto definition, goto base method
+  * document symbol search
+  * global symbol search
+
+# Setup
+
+## Building
+
+Eventually, cquery will be published in the vscode extension marketplace and you
+will be able to install and run it without any additional steps. To use cquery
+you need to clone this repository, build it, and then open vscode in this
+folder.
+
+```bash
+# Build cquery
+$ git clone https://github.com/jacobdufault/cquery --recursive
+$ cd cquery
+$ pushd third_party/sparsehash # This step will eventually be eliminated
+$ ./configure # This step will eventually be eliminated
+# sparsehash is header-only; building it is not required
+$ popd # This step will eventually be eliminated
+$ ./waf configure
+$ ./waf build
+
+# Build extension
+$ cd vscode-client
+$ npm install
+$ code .
+```
+
+After VSCode is running, you can hit `F5` to launch the extension locally. Make
+sure to open up settings and look over the configuration options. You will
+probably want to increase the number of indexers that run from 7 to 40 or 50,
+depending on how many cores are on your CPUs.
+
+## Project setup
+
+### compile_commands.json (Best)
+
+To get the most accurate index possible, you can give cquery a compilation
+database emitted from your build system of choice. For example, here's how to
+generate one in ninja. When you sync your code you should regenerate this file.
+
+```bash
+$ ninja -t compdb cxx cc > compile_commands.json
+```
+
+The `compile_commands.json` file should be in the top-level workspace directory.
+
+### cquery.extraClangArguments
+
+If for whatever reason you cannot generate a `compile_commands.json` file, you
+can add the flags to the `cquery.extraClangArguments` configuration option.
+
+### clang_args
+
+If for whatever reason you cannot generate a `compile_commands.json` file, you
+can add the flags to a file called `clang_args` located in the top-level
+workspace directory.
+
+Each argument in that file is separated by a newline. Lines starting with `#`
+are skipped. Here's an example:
+
+```
+# Language
+-xc++
+-std=c++11
+
+# Includes
+-I/work/cquery/third_party
+```
+
+# Limitations
+
+cquery is able to respond to queries quickly because it caches a huge amount of
+information. When a request comes in, cquery just looks it up in the cache
+without running many computations. As a result, there's a large memory overhead.
+For example, a full index of Chrome will take about 10gb of memory. If you
+exclude v8, webkit, and blink, it goes down to about 6.5gb.
+
+# License
+
+MIT