[build] don't rewrite style code for every build

revert of 93166aef482ea5835d87231f88d369449398ccdf

On Android, we always rewrote the style code files, which lead to gratuitous recompiles

2 files changed, 46 insertions, 17 deletions

diff --git a/scripts/generate-style-code.js b/scripts/generate-style-code.js
index dcb527e8c9..005bc022df 100644
--- a/scripts/generate-style-code.js
+++ b/scripts/generate-style-code.js
@@ -5,6 +5,8 @@ const ejs = require('ejs');
 const spec = require('mapbox-gl-style-spec').latest;
 var colorParser = require('csscolorparser');
 
+require('./style-code');
+
 function parseCSSColor(str) {
   var color = colorParser.parseCSSColor(str);
   return [
@@ -12,18 +14,6 @@ function parseCSSColor(str) {
   ];
 }
 
-global.camelize = function (str) {
-  return str.replace(/(?:^|-)(.)/g, function (_, x) {
-    return x.toUpperCase();
-  });
-}
-
-global.camelizeWithLeadingLowercase = function (str) {
-  return str.replace(/-(.)/g, function (_, x) {
-    return x.toUpperCase();
-  });
-}
-
 global.propertyType = function (property) {
   if (/-translate-anchor$/.test(property.name)) {
     return 'TranslateAnchorType';
@@ -121,16 +111,19 @@ const layers = Object.keys(spec.layer.type.values).map((type) => {
     type: type,
     layoutProperties: layoutProperties,
     paintProperties: paintProperties,
+    doc: spec.layer.type.values[type].doc,
+    layoutPropertiesByName: spec[`layout_${type}`],
+    paintPropertiesByName: spec[`paint_${type}`],
   };
 });
 
 for (const layer of layers) {
-  fs.writeFileSync(`include/mbgl/style/layers/${layer.type}_layer.hpp`, layerHpp(layer));
-  fs.writeFileSync(`src/mbgl/style/layers/${layer.type}_layer.cpp`, layerCpp(layer));
+  writeIfModified(`include/mbgl/style/layers/${layer.type}_layer.hpp`, layerHpp(layer));
+  writeIfModified(`src/mbgl/style/layers/${layer.type}_layer.cpp`, layerCpp(layer));
 
-  fs.writeFileSync(`src/mbgl/style/layers/${layer.type}_layer_properties.hpp`, propertiesHpp(layer));
-  fs.writeFileSync(`src/mbgl/style/layers/${layer.type}_layer_properties.cpp`, propertiesCpp(layer));
+  writeIfModified(`src/mbgl/style/layers/${layer.type}_layer_properties.hpp`, propertiesHpp(layer));
+  writeIfModified(`src/mbgl/style/layers/${layer.type}_layer_properties.cpp`, propertiesCpp(layer));
 }
 
 const propertySettersHpp = ejs.compile(fs.readFileSync('include/mbgl/style/conversion/make_property_setters.hpp.ejs', 'utf8'), {strict: true});
-fs.writeFileSync('include/mbgl/style/conversion/make_property_setters.hpp', propertySettersHpp({layers: layers}));
+writeIfModified('include/mbgl/style/conversion/make_property_setters.hpp', propertySettersHpp({layers: layers}));
diff --git a/scripts/style-code.js b/scripts/style-code.js
new file mode 100644
index 0000000000..156934a240
--- /dev/null
+++ b/scripts/style-code.js
@@ -0,0 +1,36 @@
+// Global functions //
+
+const fs = require('fs');
+
+global.iff = function (condition, val) {
+  return condition() ? val : "";
+};
+
+global.camelize = function (str) {
+  return str.replace(/(?:^|-)(.)/g, function (_, x) {
+    return x.toUpperCase();
+  });
+};
+
+global.camelizeWithLeadingLowercase = function (str) {
+  return str.replace(/-(.)/g, function (_, x) {
+    return x.toUpperCase();
+  });
+};
+
+global.snakeCaseUpper = function snakeCaseUpper(str) {
+  return str.replace(/-/g, "_").toUpperCase();
+};
+
+global.writeIfModified = function(filename, newContent) {
+  try {
+    const oldContent = fs.readFileSync(filename, 'utf8');
+    if (oldContent == newContent) {
+      console.warn(`* Skipping current file '${filename}'`);
+      return;
+    }
+  } catch(err) {
+  }
+  fs.writeFileSync(filename, newContent);
+  console.warn(`* Updating outdated file '${filename}'`);
+};