Use the Conan package manager (XRPLF#4367)

Introduces a conanfile.py (and a Conan recipe for RocksDB) to enable building the package with Conan, choosing more recent default versions of dependencies. It removes almost all of the CMake build files related to dependencies, and the configurations for Travis CI and GitLab CI. A new set of cross-platform build instructions are written in BUILD.md.

Includes example GitHub Actions workflow for each of Linux, macOS, Windows.

* Test on macos-12

We use the <concepts> library which was not added to Apple Clang until
version 13.1.6. The default Clang on macos-11 (the sometimes current
version of macos-latest) is 13.0.0, and the default Clang on macos-12 is
14.0.0.

Closes XRPLF#4223.

.github/workflows/nix.yml

@@ -0,0 +1,95 @@
+name: nix
+on: [push, pull_request]
+
+jobs:
+
+  test:
+    strategy:
+      matrix:
+        platform:
+          - ubuntu-latest
+          - macos-12
+        generator:
+          - Ninja
+        configuration:
+          - Release
+    runs-on: ${{ matrix.platform }}
+    env:
+      build_dir: .build
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+      - name: install Ninja on Linux
+        if: matrix.generator == 'Ninja' && runner.os == 'Linux'
+        run: sudo apt install ninja-build
+      - name: install Ninja on OSX
+        if: matrix.generator == 'Ninja' && runner.os == 'macOS'
+        run: brew install ninja
+      - name: install nproc on OSX
+        if: runner.os == 'macOS'
+        run: brew install coreutils
+      - name: choose Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: 3.9
+      - name: learn Python cache directory
+        id: pip-cache
+        run: |
+          sudo pip install --upgrade pip
+          echo "::set-output name=dir::$(pip cache dir)"
+      - name: restore Python cache directory
+        uses: actions/cache@v2
+        with:
+            path: ${{ steps.pip-cache.outputs.dir }}
+            key: ${{ runner.os }}-${{ hashFiles('.github/workflows/nix.yml') }}
+      - name: install Conan
+        run: pip install wheel 'conan>=1.52.0'
+      - name: check environment
+        run: |
+          echo ${PATH} | tr ':' '\n'
+          python --version
+          conan --version
+          cmake --version
+          env
+      - name: configure Conan
+        run: |
+          conan profile new default --detect
+          conan profile update settings.compiler.cppstd=20 default
+      - name: configure Conan on Linux
+        if: runner.os == 'Linux'
+        run: |
+          conan profile update settings.compiler.libcxx=libstdc++11 default
+      - name: learn Conan cache directory
+        id: conan-cache
+        run: |
+          echo "::set-output name=dir::$(conan config get storage.path)"
+      - name: restore Conan cache directory
+        uses: actions/cache@v2
+        with:
+            path: ${{ steps.conan-cache.outputs.dir }}
+            key: ${{ hashFiles('~/.conan/profiles/default', 'conanfile.py', 'external/rocksdb/*', '.github/workflows/nix.yml') }}
+      - name: export RocksDB
+        run: conan export external/rocksdb
+      - name: install dependencies
+        run: |
+          mkdir ${build_dir}
+          cd ${build_dir}
+          conan install .. --build missing --settings build_type=${{ matrix.configuration }} --profile:build default --profile:host default
+      - name: configure
+        run: |
+          cd ${build_dir}
+          cmake \
+            -G ${{ matrix.generator }} \
+            -DCMAKE_TOOLCHAIN_FILE:FILEPATH=build/generators/conan_toolchain.cmake \
+            -DCMAKE_BUILD_TYPE=${{ matrix.configuration }} \
+            -Dassert=ON \
+            -Dcoverage=OFF \
+            -Dreporting=OFF \
+            -Dunity=OFF \
+            ..
+      - name: build
+        run: |
+          cmake --build ${build_dir} --target rippled --parallel $(nproc)
+      - name: test
+        run: |
+          ${build_dir}/rippled --unittest --unittest-jobs $(nproc)

.github/workflows/windows.yml

@@ -0,0 +1,89 @@
+name: windows
+# We have disabled this workflow because it fails in our CI Windows
+# environment, but we cannot replicate the failure in our personal Windows
+# test environments, nor have we gone through the trouble of setting up an
+# interactive CI Windows environment.
+# We welcome contributions to diagnose or debug the problems on Windows. Until
+# then, we leave this tombstone as a reminder that we have tried (but failed)
+# to write a reliable test for Windows.
+# on: [push, pull_request]
+
+jobs:
+
+  test:
+    strategy:
+      matrix:
+        generator:
+          - Visual Studio 16 2019
+        configuration:
+          - Release
+    runs-on: windows-2019
+    env:
+      build_dir: .build
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+      - name: choose Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: 3.9
+      - name: learn Python cache directory
+        id: pip-cache
+        run: |
+          pip install --upgrade pip
+          echo "::set-output name=dir::$(pip cache dir)"
+      - name: restore Python cache directory
+        uses: actions/cache@v2
+        with:
+            path: ${{ steps.pip-cache.outputs.dir }}
+            key: ${{ runner.os }}-${{ hashFiles('.github/workflows/windows.yml') }}
+      - name: install Conan
+        run: pip install wheel 'conan>=1.52.0'
+      - name: check environment
+        run: |
+          $env:PATH -split ';'
+          python --version
+          conan --version
+          cmake --version
+          dir env:
+      - name: configure Conan
+        run: |
+          conan profile new default --detect
+          conan profile update settings.compiler.cppstd=20 default
+          conan profile update settings.compiler.runtime=MT default
+          conan profile update settings.compiler.toolset=v141 default
+      - name: learn Conan cache directory
+        id: conan-cache
+        run: |
+          echo "::set-output name=dir::$(conan config get storage.path)"
+      - name: restore Conan cache directory
+        uses: actions/cache@v2
+        with:
+            path: ${{ steps.conan-cache.outputs.dir }}
+            key: ${{ hashFiles('~/.conan/profiles/default', 'conanfile.py', 'external/rocksdb/*', '.github/workflows/windows.yml') }}
+      - name: export RocksDB
+        run: conan export external/rocksdb
+      - name: install dependencies
+        run: |
+          mkdir $env:build_dir
+          cd $env:build_dir
+          conan install .. --build missing --settings build_type=${{ matrix.configuration }}
+      - name: configure
+        run: |
+          $env:build_dir
+          cd $env:build_dir
+          pwd
+          ls
+          cmake `
+            -G "${{ matrix.generator }}" `
+            -DCMAKE_TOOLCHAIN_FILE:FILEPATH=build/generators/conan_toolchain.cmake `
+            -Dassert=ON `
+            -Dreporting=OFF `
+            -Dunity=OFF `
+            ..
+      - name: build
+        run: |
+          cmake --build $env:build_dir --target rippled --config ${{ matrix.configuration }} --parallel $env:NUMBER_OF_PROCESSORS
+      - name: test
+        run: |
+          & "$env:build_dir\${{ matrix.configuration }}\rippled.exe" --unittest