add cpp api reference (#618)

Summary:

Adding cpp docs and updating the build system for the docs to support doxygen and breath (connects sphinx and doxygen).

Reviewed By: svekars, cccclai

Differential Revision: D49924199

Author: JacobSzwejbka

.ci/docker/build.sh

@@ -36,6 +36,8 @@ TORCH_VERSION=$(cat ci_commit_pins/pytorch.txt)
 TORCHAUDIO_VERSION=$(cat ci_commit_pins/audio.txt)
 TORCHVISION_VERSION=$(cat ci_commit_pins/vision.txt)
 
+BUILD_DOCS=1
+
 # Copy requirements-lintrunner.txt from root to here
 cp ../../requirements-lintrunner.txt ./
 
@@ -51,6 +53,7 @@ docker build \
   --build-arg "TORCHVISION_VERSION=${TORCHVISION_VERSION}.${NIGHTLY}" \
   --build-arg "BUCK2_VERSION=${BUCK2_VERSION}" \
   --build-arg "LINTRUNNER=${LINTRUNNER}" \
+  --build-arg "BUILD_DOCS=${BUILD_DOCS}" \
   -f "${OS}"/Dockerfile \
   "$@" \
   .

.ci/docker/common/install_docs_reqs.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+set -ex
+
+if [ -n "$BUILD_DOCS" ]; then
+  apt-get update
+  # Ignore error if gpg-agent doesn't exist (for Ubuntu 16.04)
+  apt-get install -y gpg-agent || :
+
+  curl --retry 3 -sL https://deb.nodesource.com/setup_16.x | sudo -E bash -
+  sudo apt-get install -y nodejs
+
+  curl --retry 3 -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+  echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+
+  apt-get update
+  apt-get install -y --no-install-recommends yarn
+  yarn global add katex --prefix /usr/local
+
+  sudo apt-get -y install doxygen
+
+  apt-get autoclean && apt-get clean
+  rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+fi

.ci/docker/requirements-ci.txt

@@ -15,8 +15,11 @@ hypothesis==6.84.2
 parameterized==0.9.0
 
 # Doc build requirements
-sphinx==5.0.0
+sphinx==4.5.0
 sphinx-gallery
+breathe==4.35.0
+exhale==0.3.6
+docutils==0.16
 matplotlib
 # PyTorch Theme
 -e git+https://github.com/pytorch/pytorch_sphinx_theme.git#egg=pytorch_sphinx_theme

.ci/docker/ubuntu/Dockerfile

@@ -24,6 +24,11 @@ RUN bash ./install_buck.sh && rm install_buck.sh
 COPY ./common/install_user.sh install_user.sh
 RUN bash ./install_user.sh && rm install_user.sh
 
+# Install docs
+ARG BUILD_DOCS
+COPY ./common/install_docs_reqs.sh install_docs_reqs.sh
+RUN bash ./install_docs_reqs.sh && rm install_docs_reqs.sh
+
 # Install conda and other dependencies
 ARG MINICONDA_VERSION
 ARG PYTHON_VERSION

.github/workflows/doc-build.yml

@@ -46,6 +46,7 @@ jobs:
 
         # Build docset:
         cd docs
+        doxygen source/Doxyfile
         make html
         cd ..
 

docs/Makefile

@@ -2,7 +2,7 @@
 #
 
 # You can set these variables from the command line.
-SPHINXOPTS    = -WT --keep-going
+# SPHINXOPTS    = -WT --keep-going TODO(T165752164) fix sphinx warnings around preprocess macros in cpp like __ET_DEPRECATED
 SPHINXBUILD   = sphinx-build
 SPHINXPROJ    = ExecuTorch
 SOURCEDIR     = source