[build] Check documentation coverage on CI

Add a CI target that checks documentation coverage and reports back to
github. While at it, change the output of doxy-coverage to a json file
so it is easy to consume.

4 files changed, 108 insertions, 9 deletions

diff --git a/circle.yml b/circle.yml
index 4a54e06931..477556797e 100644
--- a/circle.yml
+++ b/circle.yml
@@ -39,6 +39,7 @@ workflows:
       - linux-gcc49-debug:
           name: linux-gcc4.9-debug
       - linux-gcc5-debug-coverage
+      - linux-doxygen
       - ios-debug
       - ios-release-template:
           name: ios-release
@@ -865,6 +866,31 @@ jobs:
             ./codecov -c
 
 # ------------------------------------------------------------------------------
+  linux-doxygen:
+    docker:
+      - image: mbgl/linux-gcc-5:54f59e3ac5
+    resource_class: large
+    working_directory: /src
+    environment:
+      LIBSYSCONFCPUS: 2
+      JOBS: 2
+      BUILDTYPE: Debug
+      WITH_EGL: 1
+      WITH_COVERAGE: 1
+    steps:
+      - install-dependencies
+      - run:
+          name: Install doxygen
+          command: apt update && apt install -y doxygen
+      - build-linux
+      - save-dependencies
+      - run:
+          name: Check documentation coverage
+          command: |
+              platform/linux/ninja -C "build/linux-$(uname -m)/Debug" doxygen_coverage
+              scripts/publish_doxygen_coverage.js "build/linux-$(uname -m)/Debug/doxygen-coverage.json"
+
+# ------------------------------------------------------------------------------
   ios-debug:
     macos:
       xcode: "10.1.0"
diff --git a/cmake/doxygen.cmake b/cmake/doxygen.cmake
index c7e2fab3c4..b61e878f88 100644
--- a/cmake/doxygen.cmake
+++ b/cmake/doxygen.cmake
@@ -11,7 +11,7 @@ if(DOXYGEN_FOUND)
     )
 
     add_custom_target(doxygen_coverage
-        COMMAND ${CMAKE_SOURCE_DIR}/scripts/doxy-coverage.py --noerror "${CMAKE_BINARY_DIR}/docs/xml"
+        COMMAND ${CMAKE_SOURCE_DIR}/scripts/doxy-coverage.py --quiet --noerror --json="${CMAKE_BINARY_DIR}/doxygen-coverage.json" "${CMAKE_BINARY_DIR}/docs/xml"
         COMMENT "Checking documentation coverage"
         DEPENDS generate_xml_doxygen
     )
diff --git a/scripts/doxy-coverage.py b/scripts/doxy-coverage.py
index 9c39b349aa..b721d57a7d 100755
--- a/scripts/doxy-coverage.py
+++ b/scripts/doxy-coverage.py
@@ -158,18 +158,25 @@ def report (files, exclude_dirs):
 		total_yes += doc_yes
 		total_no  += doc_no
 
-		print ('%3d%% - %s - (%d of %d)'%(doc_per, f, doc_yes, (doc_yes + doc_no)))
+		if not ns.quiet:
+			print ('%3d%% - %s - (%d of %d)'%(doc_per, f, doc_yes, (doc_yes + doc_no)))
 
-		defs_sorted = defs.keys()
-		defs_sorted.sort()
-		for d in defs_sorted:
-			if not defs[d]:
-				print ("\t", d)
+			defs_sorted = defs.keys()
+			defs_sorted.sort()
+			for d in defs_sorted:
+				if not defs[d]:
+					print ("\t", d)
 
 	total_all = total_yes + total_no
 	total_per = total_yes * 100 / total_all
-	print()
-	print("%d%% API documentation coverage" %(total_per))
+	if not ns.quiet:
+		print()
+		print("%d%% API documentation coverage (%d out of %d)" %(total_per, total_yes, total_all))
+
+	if ns.json:
+		with open(ns.json, "w") as f:
+			f.write('{"documented": %d, "total": %d}\n' % (total_yes, total_all))
+
 	return (ns.threshold - total_per, 0)[total_per > ns.threshold]
 
 
@@ -179,6 +186,8 @@ def main():
 	parser.add_argument ("dir",         action="store",      help="Path to Doxygen's XML doc directory")
 	parser.add_argument ("--noerror",   action="store_true", help="Do not return error code after execution")
 	parser.add_argument ("--threshold", action="store",      help="Min acceptable coverage percentage (Default: %s)"%(ACCEPTABLE_COVERAGE), default=ACCEPTABLE_COVERAGE, type=int)
+	parser.add_argument ("--quiet",     action="store_true", help="Don't output report to standard output")
+	parser.add_argument ("--json",      action="store",      help="Output json coverage report to specified json file")
 	parser.add_argument("--excludedirs", nargs='+', help="List of directories to be excluded from coverage analysis", type=str, default=[])
 
 
diff --git a/scripts/publish_doxygen_coverage.js b/scripts/publish_doxygen_coverage.js
new file mode 100755
index 0000000000..e3e564a3e1
--- /dev/null
+++ b/scripts/publish_doxygen_coverage.js
@@ -0,0 +1,64 @@
+#!/usr/bin/env node
+
+const jwt = require('jsonwebtoken');
+const github = require('@octokit/rest')();
+const fs = require('fs');
+
+const SIZE_CHECK_APP_ID = 14028;
+const SIZE_CHECK_APP_INSTALLATION_ID = 229425;
+
+var coverage;
+
+try {
+    coverage = JSON.parse(fs.readFileSync(process.argv[2]));
+    if (typeof coverage.documented !== 'number' || typeof coverage.total !== 'number' ||
+        coverage.documented > coverage.total) {
+        throw new Error('Invalid coverage.json file');
+    }
+} catch (error) {
+    console.log('Failed to parse json file with coverage data: ', error);
+    process.exit(1);
+}
+
+process.on('unhandledRejection', error => {
+    console.log(error);
+    process.exit(1);
+});
+
+const pk = process.env['SIZE_CHECK_APP_PRIVATE_KEY'];
+if (!pk) {
+    console.log('Fork PR; not publishing size.');
+    process.exit(0);
+}
+
+const key = Buffer.from(pk, 'base64').toString('binary');
+const payload = {
+    exp: Math.floor(Date.now() / 1000) + 60,
+    iat: Math.floor(Date.now() / 1000),
+    iss: SIZE_CHECK_APP_ID
+};
+
+const token = jwt.sign(payload, key, {algorithm: 'RS256'});
+github.authenticate({type: 'app', token});
+
+github.apps.createInstallationToken({installation_id: SIZE_CHECK_APP_INSTALLATION_ID})
+    .then(({data}) => {
+        github.authenticate({type: 'token', token: data.token});
+        const percentage = coverage.documented * 100 / coverage.total;
+        const title = `${percentage.toFixed(2)}%`;
+
+        return github.checks.create({
+            owner: 'mapbox',
+            repo: 'mapbox-gl-native',
+            name: 'Doxygen coverage',
+            head_branch: process.env['CIRCLE_BRANCH'],
+            head_sha: process.env['CIRCLE_SHA1'],
+            status: 'completed',
+            conclusion: 'success',
+            completed_at: new Date().toISOString(),
+            output: {
+                title,
+                summary: `There is doxygen documentation for ${percentage}% of the public symbols (${coverage.documented} out of ${coverage.total})`
+            }
+        });
+    });