[offline] Add option to pass geojson input file

2 files changed, 77 insertions, 14 deletions

diff --git a/bin/offline.cpp b/bin/offline.cpp
index 603f0b848a..2da47a4476 100644
--- a/bin/offline.cpp
+++ b/bin/offline.cpp
@@ -1,6 +1,7 @@
 #include <mbgl/util/default_styles.hpp>
 #include <mbgl/util/run_loop.hpp>
 #include <mbgl/util/string.hpp>
+#include <mbgl/util/geojson.hpp>
 
 #include <mbgl/storage/default_file_source.hpp>
 
@@ -11,9 +12,47 @@
 #include <csignal>
 #include <atomic>
 #include <sstream>
+#include <fstream>
 
 using namespace std::literals::chrono_literals;
 
+std::string readFile(const std::string& fileName) {
+    std::ifstream stream(fileName.c_str());
+    if (!stream.good()) {
+        throw std::runtime_error("Cannot read file: " + fileName);
+    }
+    
+    std::stringstream buffer;
+    buffer << stream.rdbuf();
+    stream.close();
+    
+    return buffer.str();
+}
+
+mapbox::geometry::geometry<double> parseGeometry(const std::string& json) {
+    using namespace mapbox::geojson;
+    auto geojson = parse(json);
+    return geojson.match(
+        [](const geometry& geom) {
+            return geom;
+        },
+        [](const feature& feature) {
+            return feature.geometry;
+        },
+        [](const feature_collection& featureCollection) {
+            if (featureCollection.size() < 1) {
+                throw std::runtime_error("No features in feature collection");
+            }
+            geometry_collection geometries;
+            
+            for (auto feature : featureCollection) {
+                geometries.push_back(feature.geometry);
+            }
+            
+            return geometries;
+        });
+}
+
 int main(int argc, char *argv[]) {
     args::ArgumentParser argumentParser("Mapbox GL offline tool");
     args::HelpFlag helpFlag(argumentParser, "help", "Display this help menu", {'h', "help"});
@@ -22,11 +61,19 @@ int main(int argc, char *argv[]) {
     args::ValueFlag<std::string> styleValue(argumentParser, "URL", "Map stylesheet", {'s', "style"});
     args::ValueFlag<std::string> outputValue(argumentParser, "file", "Output database file name", {'o', "output"});
     args::ValueFlag<std::string> apiBaseValue(argumentParser, "URL", "API Base URL", {'a', "apiBaseURL"});
-
-    args::ValueFlag<double> northValue(argumentParser, "degrees", "North latitude", {"north"});
-    args::ValueFlag<double> westValue(argumentParser, "degrees", "West longitude", {"west"});
-    args::ValueFlag<double> southValue(argumentParser, "degrees", "South latitude", {"south"});
-    args::ValueFlag<double> eastValue(argumentParser, "degrees", "East longitude", {"east"});
+    
+    // LatLngBounds
+    args::Group latLngBoundsGroup(argumentParser, "LatLng bounds:", args::Group::Validators::AllOrNone);
+    args::ValueFlag<double> northValue(latLngBoundsGroup, "degrees", "North latitude", {"north"});
+    args::ValueFlag<double> westValue(latLngBoundsGroup, "degrees", "West longitude", {"west"});
+    args::ValueFlag<double> southValue(latLngBoundsGroup, "degrees", "South latitude", {"south"});
+    args::ValueFlag<double> eastValue(latLngBoundsGroup, "degrees", "East longitude", {"east"});
+    
+    // Geometry
+    args::Group geoJSONGroup(argumentParser, "GeoJson geometry:", args::Group::Validators::AllOrNone);
+    args::ValueFlag<std::string> geometryValue(geoJSONGroup, "file", "GeoJSON file containing the region geometry", {"geojson"});
+    
+    
     args::ValueFlag<double> minZoomValue(argumentParser, "number", "Min zoom level", {"minZoom"});
     args::ValueFlag<double> maxZoomValue(argumentParser, "number", "Max zoom level", {"maxZoom"});
     args::ValueFlag<double> pixelRatioValue(argumentParser, "number", "Pixel ratio", {"pixelRatio"});
@@ -48,23 +95,39 @@ int main(int argc, char *argv[]) {
 
     std::string style = styleValue ? args::get(styleValue) : mbgl::util::default_styles::streets.url;
 
-    // Bay area
-    const double north = northValue ? args::get(northValue) : 37.2;
-    const double west = westValue ? args::get(westValue) : -122.8;
-    const double south = southValue ? args::get(southValue) : 38.1;
-    const double east = eastValue ? args::get(eastValue) : -121.7;
-
     const double minZoom = minZoomValue ? args::get(minZoomValue) : 0.0;
     const double maxZoom = maxZoomValue ? args::get(maxZoomValue) : 15.0;
     const double pixelRatio = pixelRatioValue ? args::get(pixelRatioValue) : 1.0;
     const std::string output = outputValue ? args::get(outputValue) : "offline.db";
+    
+    using namespace mbgl;
+    
+    OfflineRegionDefinition definition = [&]() {
+        if (geometryValue) {
+            try {
+                std::string json = readFile(geometryValue.Get());
+                auto geometry = parseGeometry(json);
+                return OfflineRegionDefinition{ OfflineGeometryRegionDefinition(style, geometry, minZoom, maxZoom, pixelRatio) };
+            } catch(std::runtime_error e) {
+                std::cerr << "Could not parse geojson file " << geometryValue.Get() << ": " << e.what() << std::endl;
+                exit(1);
+            }
+        } else {
+            // Bay area
+            const double north = northValue ? args::get(northValue) : 37.2;
+            const double west = westValue ? args::get(westValue) : -122.8;
+            const double south = southValue ? args::get(southValue) : 38.1;
+            const double east = eastValue ? args::get(eastValue) : -121.7;
+            LatLngBounds boundingBox = LatLngBounds::hull(LatLng(north, west), LatLng(south, east));
+            return OfflineRegionDefinition{ OfflineTilePyramidRegionDefinition(style, boundingBox, minZoom, maxZoom, pixelRatio) };
+        }
+    }();
 
     const char* tokenEnv = getenv("MAPBOX_ACCESS_TOKEN");
     const std::string token = tokenValue ? args::get(tokenValue) : (tokenEnv ? tokenEnv : std::string());
     
     const std::string apiBaseURL = apiBaseValue ? args::get(apiBaseValue) : mbgl::util::API_BASE_URL;
 
-    using namespace mbgl;
 
     util::RunLoop loop;
     DefaultFileSource fileSource(output, ".");
@@ -73,8 +136,7 @@ int main(int argc, char *argv[]) {
     fileSource.setAccessToken(token);
     fileSource.setAPIBaseURL(apiBaseURL);
 
-    LatLngBounds boundingBox = LatLngBounds::hull(LatLng(north, west), LatLng(south, east));
-    OfflineTilePyramidRegionDefinition definition(style, boundingBox, minZoom, maxZoom, pixelRatio);
+
     OfflineRegionMetadata metadata;
 
     class Observer : public OfflineRegionObserver {
diff --git a/platform/linux/config.cmake b/platform/linux/config.cmake
index c1eb4bfe12..b55cedcacb 100644
--- a/platform/linux/config.cmake
+++ b/platform/linux/config.cmake
@@ -81,6 +81,7 @@ macro(mbgl_platform_core)
     target_add_mason_package(mbgl-core PUBLIC libjpeg-turbo)
     target_add_mason_package(mbgl-core PUBLIC webp)
     target_add_mason_package(mbgl-core PRIVATE icu)
+    target_add_mason_package(mbgl-core PUBLIC geojson)
 
     target_link_libraries(mbgl-core
         PRIVATE nunicode