Implement libr crate for dynamic runtime symbol resolution (#205)

* POC of `libr` crate for dynamic runtime symbol resolution

* Temp support for globals

* Better initialization routine

* Use `libr::has::` module

* Add mutable global support

* Pull default up into attribute

* Try a Windows specific function

* Expose individual initialization functions

* Update unix startup code to use libr

* Get tests working again with libr setup

* Remove hard coded shared library path

* Add windows specific types file for `Rstart`

* Fix up cfg passthrough

* Expose `Rgraphapp` as a 2nd order export

* Fix thinkos

* Needlessly complicating things

* Rename

* Remove remaining `extern "C" {` usages

* Start `extern "C" {` removal from shim

* Move all globals over

* Start chipping away at list of libR-sys imports

* Another chunk of function exports

* `R_CStackLimit` is a mutable global

* More functions

* Power through last easy functions

* Move over `SEXPTYPE`s

* Move over `Rboolean`

* Move over `R_xlen_t`

* Move over `Rbyte`

* Move over `Rcomplex`

* Move over `SEXP`

* Account for awkward variadic function signatures

* Remove windows usage of `libR_shim`

* Move types to their own file

* Expose graphics device types and functions

Using an opaque pointer trick

* Tweak import for windows

* Rip out `libR-sys` and `libR-shim`

* Remove `-undefined dynamic_lookup`, yay safety!

* No longer need `post-install.sh`

* Remove `install_name_tool` usage in CI

* Remove unsetting of `DYLD_INSERT_LIBRARIES`

We don't actually set this particular env var anyways, so this didn't do anything, but we definitely don't need it now!

* Remove comment about testing ark

* Add note about how CI works

* No longer need R or `dll2lib.R` in build steps

* No longer need `dll2lib.R`

* Don't need this panic import

* Use `libr::*` in the most annoying places

* Fiddle with test imports

* Preemptively open and leak the 4 R DLLs on Windows

So other R packages like stats can find and use them without needing the DLL folder on the PATH

* Add `RLibraries` struct to reduce duplication

* Tweak unused library field names

* Use `get()` and `set()` for mutable globals

* Allow unused imports on unix, where we don't use this file yet

* Open on unix with `RTLD_GLOBAL`

* Source `ldpaths` to set appropriate library path env var

* Simpler approach with `bash -c`

* Use `sh` and `printf` for simplicity and portability

.cargo/config.toml

@@ -1,16 +1,3 @@
-
-[target.x86_64-apple-darwin]
-rustflags = [
-  "-C", "link-arg=-undefined",
-  "-C", "link-arg=dynamic_lookup",
-]
-
-[target.aarch64-apple-darwin]
-rustflags = [
-  "-C", "link-arg=-undefined",
-  "-C", "link-arg=dynamic_lookup",
-]
-
 # Increase stack space on Windows to 8m
 # See https://github.com/posit-dev/positron/issues/1975
 

.github/workflows/amalthea-ci.yml

@@ -27,6 +27,9 @@ jobs:
         run: |
             cargo build --verbose
 
+      # Ubuntu runners already have a version of R installed.
+      # Unit tests "automatically" find and set `R_HOME` if it isn't set by
+      # calling `R RHOME`. See the testing version of `start_r()` for this.
       - name: Run Unit Tests
         id: amalthea-test
         run: |

.github/workflows/release.yml

@@ -123,29 +123,12 @@ jobs:
               run: |
                   echo "~/${{matrix.homebrew_folder}}/bin" >> $GITHUB_PATH
 
-            # Determine R_HOME (for building ark)
-            - name: Find Homebrew R installation
-              id: r_installation
-              run: |
-                  # Path to the Homebrew build of R, e.g. /Users/user229818/homebrew/Cellar/r
-                  R_FOLDER=~/${{matrix.homebrew_folder}}/Cellar/r
-                  # Get the first (and generally) only installed version, e.g. 4.2.2
-                  R_VERSION=$(ls ${R_FOLDER} | head -1)
-                  # Form the path to the R binary, e.g. /Users/user229818/homebrew/Cellar/r/4.2.2/bin/R
-                  R_EXECUTABLE="${R_FOLDER}/${R_VERSION}/bin/R"
-                  # Invoke the R binary to determine its RHOME directory (usually lib/R)
-                  R_HOME=$(${R_EXECUTABLE} RHOME)
-                  # Output the result for consumption in later steps
-                  echo "Using R at ${R_HOME}"
-                  echo "r_home=${R_HOME}" >> $GITHUB_OUTPUT
-
             # Compile
             - name: Compile ARK (${{ matrix.arch }})
               env:
                   npm_config_arch: ${{ matrix.arch }}
                   ARK_BUILD_TYPE: ${{ matrix.flavor }}
                   RUST_TARGET: ${{ matrix.rust_target_prefix }}-apple-darwin
-                  R_HOME: ${{ steps.r_installation.outputs.r_home }}
                   CARGO_FLAGS:
                   PKG_CONFIG_ALLOW_CROSS: 1
               run: |
@@ -158,22 +141,10 @@ jobs:
                   # Enter the build directory
                   pushd target/${{ matrix.rust_target_prefix }}-apple-darwin/${{ matrix.flavor }}
 
-                  # On macOS, we use install_name_tool to fix up the link to libR.dylib.
-                  #
-                  # Note that we still try to link with '-undefined dynamic_lookup', just to ensure that
-                  # linking succeeds when we compile against a version of R compiled for a different
-                  # architecture. This is mostly relevant when producing x86_64 builds of ark on an arm64
-                  # machine.
-                  #
-                  # However, because using libR-sys still implies that the path to the R library ends up in
-                  # the library load list, we have to modify that after the fact anyhow.
-                  OLD_LIBR_PATH=$(otool -L ark | grep libR.dylib | cut -c2- | cut -d ' ' -f1)
-                  echo "Fixing path to shared R library at ${OLD_LIBR_PATH}..."
-                  install_name_tool -change "${OLD_LIBR_PATH}" "@rpath/libR.dylib" ark
-
                   # Compress the kernel to an archive
                   ARCHIVE="$GITHUB_WORKSPACE/ark-${{ needs.get_version.outputs.ARK_VERSION }}-${{ matrix.flavor }}-darwin-${{ matrix.arch }}.zip"
                   zip -Xry $ARCHIVE ark
+
                   popd
 
             # Create build artifact
@@ -204,33 +175,10 @@ jobs:
             - name: Checkout sources
               uses: actions/checkout@v4
 
-            - name: Setup R
-              uses: r-lib/actions/setup-r@v2
-              with:
-                  r-version: '4.3.2'
-
-            - name: Find R installation
-              id: r_installation
-              shell: bash
-              run: |
-                  R_HOME="C:\R"
-                  R_SCRIPT="${R_HOME}\bin\x64\Rscript.exe"
-                  echo "Using R at ${R_HOME}"
-                  echo "Using Rscript at ${R_SCRIPT}"
-                  # Output the result for consumption in later steps
-                  echo "r_home=${R_HOME}" >> $GITHUB_OUTPUT
-                  echo "r_script=${R_SCRIPT}" >> $GITHUB_OUTPUT
-
-            - name: Generate LIB from DLL
-              shell: cmd
-              run: |
-                  ${{ steps.r_installation.outputs.r_script }} "scripts\windows\dll2lib.R"
-
             - name: Compile ARK
               env:
                   ARK_BUILD_TYPE: ${{ matrix.flavor }}
                   RUST_TARGET: ${{ matrix.rust_target_prefix }}-pc-windows-msvc
-                  R_HOME: ${{ steps.r_installation.outputs.r_home }}
               shell: cmd
               run: |
                   cargo clean

.vscode/tasks.json

@@ -3,18 +3,7 @@
     "tasks": [
         {
             "type": "shell",
-            "osx": {
-                "command": "cargo build && scripts/post-install.sh"
-            },
-            "windows": {
-                // Note that the environment variable, R_HOME, must be set prior to `cargo build`
-                // in order to build the ark dependency libR-sys. Once libR-sys is built,
-                // R_HOME is not required for subsequent runs of `cargo build`.
-                // Prior to running `cargo build`, execute something like this:
-                // PowerShell:    $env:R_HOME = "C:\\Program Files\\R\\R-4.3.2"
-                // bash:          export R_HOME="C:\\Program Files\\R\\R-4.3.2"
-                "command": "cargo build"
-            },
+            "command": "cargo build",
             "problemMatcher": [
                 "$rustc"
             ],