# vcpkg_from_gitlab

Download and extract a project from Gitlab instances. Enables support for `install --head`.

## Usage:
```cmake
vcpkg_from_gitlab(
    GITLAB_URL <https://gitlab.com>
    OUT_SOURCE_PATH <SOURCE_PATH>
    REPO <gitlab-org/gitlab-ce>
    [REF <v10.7.3>]
    [SHA512 <45d0d7f8cc350...>]
    [HEAD_REF <master>]
    [PATCHES <patch1.patch> <patch2.patch>...]
)
```

## Parameters:

### GITLAB_URL
The URL of the Gitlab instance to use.

### OUT_SOURCE_PATH
Specifies the out-variable that will contain the extracted location.

This should be set to `SOURCE_PATH` by convention.

### REPO
The organization or user plus the repository name on the Gitlab instance.

### REF
A stable git commit-ish (ideally a tag) that will not change contents. **This should not be a branch.**

For repositories without official releases, this can be set to the full commit id of the current latest master.

If `REF` is specified, `SHA512` must also be specified.

### SHA512
The SHA512 hash that should match the archive (${GITLAB_URL}/${REPO}/-/archive/${REF}/${REPO_NAME}-${REF}.tar.gz).
The REPO_NAME variable is parsed from the value of REPO.

This is most easily determined by first setting it to `1`, then trying to build the port. The error message will contain the full hash, which can be copied back into the portfile.

### HEAD_REF
The unstable git commit-ish (ideally a branch) to pull for `--head` builds.

For most projects, this should be `master`. The chosen branch should be one that is expected to be always buildable on all supported platforms.

### PATCHES
A list of patches to be applied to the extracted sources.

Relative paths are based on the port directory.

## Notes:
At least one of `REF` and `HEAD_REF` must be specified, however it is preferable for both to be present.

This exports the `VCPKG_HEAD_VERSION` variable during head builds.

## Examples:
* [curl][https://github.com/Microsoft/vcpkg/blob/master/ports/curl/portfile.cmake#L75]
* [folly](https://github.com/Microsoft/vcpkg/blob/master/ports/folly/portfile.cmake#L15)
* [z3](https://github.com/Microsoft/vcpkg/blob/master/ports/z3/portfile.cmake#L13)


## Source
[scripts/cmake/vcpkg_from_gitlab.cmake](https://github.com/Microsoft/vcpkg/blob/master/scripts/cmake/vcpkg_from_gitlab.cmake)