# MacOS Deployment

The `macdeployqtplus` script should not be run manually. Instead, after building as usual:

```bash
cmake --build build --target deploy
```

When complete, it will have produced `Gridcoin.dmg`.

## SDK Extraction

### Step 1: Obtaining `Xcode.app`

Our current macOS SDK can be extracted from
[Xcode_15.xip](https://download.developer.apple.com/Developer_Tools/Xcode_15/Xcode_15.xip).
An Apple ID is needed to download this.

The `sha256sum` of the downloaded XIP archive should be `4daaed2ef2253c9661779fa40bfff50655dc7ec45801aba5a39653e7bcdde48e`.

To extract the `.xip` on Linux:

```bash
# Install/clone tools needed for extracting Xcode.app
apt install cpio
git clone https://github.com/bitcoin-core/apple-sdk-tools.git

# Unpack the xip and place the resulting Xcode.app in your current
# working directory
python3 apple-sdk-tools/extract_xcode.py -f Xcode_15.xip | cpio -d -i
```

On macOS:

```bash
xip -x Xcode_15.xip
```

### Step 2: Generating the SDK tarball from `Xcode.app`

To generate the SDK, run the script [`gen-sdk`](./gen-sdk) with the
path to `Xcode.app` (extracted in the previous stage) as the first argument.

```bash
./contrib/macdeploy/gen-sdk '/path/to/Xcode.app'
```

The generated archive should be: `Xcode-15.0-15A240d-extracted-SDK-with-libcxx-headers.tar.gz`.
The `sha256sum` should be `c0c2e7bb92c1fee0c4e9f3a485e4530786732d6c6dd9e9f418c282aa6892f55d`.

## Cross Platform Building

Download and extract the SDK to depends/SDKs. Then build the dependencies from
the depends directory and deploy the .dmg:

```bash
cd depends
make HOST=x86_64-apple-darwin
cd ..
cmake -B build --toolchain depends/x86_64-apple-darwin/toolchain.cmake
cmake --build build -j$(nproc)
cmake --build build --target deploy
```

## NOTE: the below deterministic macOS DMG notes below are retained for historical purposes.
Since gitian has been removed, we are deciding the best path forward for deterministic builds.
Bitcoin is heading in the direction of Guix. Gridcoin may do the same, but this has not been
decided yet by the Gridcoin development team and community.

## Deterministic macOS DMG Notes
Working macOS DMGs are created in Linux by combining a recent `clang`, the Apple
`binutils` (`ld`, `ar`, etc) and DMG authoring tools.

Apple uses `clang` extensively for development and has upstreamed the necessary
functionality so that a vanilla clang can take advantage. It supports the use of `-F`,
`-target`, `-mmacosx-version-min`, and `-isysroot`, which are all necessary when
building for macOS.

Apple's version of `binutils` (called `cctools`) contains lots of functionality missing in the
FSF's `binutils`. In addition to extra linker options for frameworks and sysroots, several
other tools are needed as well such as `install_name_tool`, `lipo`, and `nmedit`. These
do not build under Linux, so they have been patched to do so. The work here was used as
a starting point: [mingwandroid/toolchain4](https://github.com/mingwandroid/toolchain4).

In order to build a working toolchain, the following source packages are needed from
Apple: `cctools`, `dyld`, and `ld64`.

These tools inject timestamps by default, which produce non-deterministic binaries. The
`ZERO_AR_DATE` environment variable is used to disable that.

This version of `cctools` has been patched to use the current version of `clang`'s headers
and its `libLTO.so` rather than those from `llvmgcc`, as it was originally done in `toolchain4`.

To complicate things further, all builds must target an Apple SDK. These SDKs are free to
download, but not redistributable. See the SDK Extraction notes above for how to obtain it.

The Gitian descriptors build 2 sets of files: Linux tools, then Apple binaries which are
created using these tools. The build process has been designed to avoid including the
SDK's files in Gitian's outputs. All interim tarballs are fully deterministic and may be freely
redistributed.

[`xorrisofs`](https://www.gnu.org/software/xorriso/) is used to create the DMG.

`xorrisofs` cannot compress DMGs, so afterwards, the DMG tool from the
`libdmg-hfsplus` project is used to compress it. There are several bugs in this
tool and its maintainer has seemingly abandoned the project.

The DMG tool has the ability to create DMGs from scratch as well, but this functionality is
broken. Only the compression feature is currently used. Ideally, the creation could be fixed
and `xorrisofs` would no longer be necessary.

Background images and other features can be added to DMG files by inserting a
`.DS_Store` during creation.

As of OS X 10.9 Mavericks, using an Apple-blessed key to sign binaries is a requirement in
order to satisfy the new Gatekeeper requirements. Because this private key cannot be
shared, we'll have to be a bit creative in order for the build process to remain somewhat
deterministic. Here's how it works for Bitcoin—Gridcoin does not follow this process yet:

- Builders use Gitian to create an unsigned release. This outputs an unsigned DMG which
  users may choose to bless and run. It also outputs an unsigned app structure in the form
  of a tarball, which also contains all of the tools that have been previously (deterministically)
  built in order to create a final DMG.
- The Apple keyholder uses this unsigned app to create a detached signature, using the
  script that is also included there. Detached signatures are available from this [repository](https://github.com/bitcoin-core/bitcoin-detached-sigs).
- Builders feed the unsigned app + detached signature back into Gitian. It uses the
  pre-built tools to recombine the pieces into a deterministic DMG.
