[ion] Makefile linux: simplify build system by generating a header

ion/src/simulator/linux/Makefile

@@ -29,14 +29,19 @@ LDFLAGS += -ljpeg
 
 $(eval $(call rule_for, \
   LINUX_ASSETS, \
-  ion/src/simulator/linux/assets.s ion/src/simulator/linux/images.h, \
+  ion/src/simulator/linux/assets.s, \
   $(assets_paths), \
-  $$(PYTHON) ion/src/simulator/linux/assets.py --files $(assets) --header $$@ --implementation $$@, \
+  $$(PYTHON) ion/src/simulator/linux/assets.py --files $(assets) --implementation $$@, \
   global \
 ))
 
-assets_address_ranges_declaration = $(foreach i,$(assets),extern unsigned char _ion_simulator_$(basename $(i))_start;)
-assets_address_ranges_declaration += $(foreach i,$(assets),extern unsigned char _ion_simulator_$(basename $(i))_end;)
-assets_address_ranges_definition = $(foreach i,$(assets), {"$(i)", &_ion_simulator_$(basename $(i))_start, &_ion_simulator_$(basename $(i))_end},)
+# The header is refered to as <ion/src/simulator/linux/images.h> so make sure it's findable this way
+SFLAGS += -I$(BUILD_DIR)
 
-$(call object_for,ion/src/simulator/linux/images.cpp): CXXFLAGS += -DASSETS_ADDRESS_RANGES_DECLARATION='$(assets_address_ranges_declaration)' -DASSETS_ADDRESS_RANGES_DEFINITION='$(assets_address_ranges_definition)'
+$(eval $(call rule_for, \
+  LINUX_ASSETS, \
+  ion/src/simulator/linux/images.h, \
+  $(assets_paths), \
+  $$(PYTHON) ion/src/simulator/linux/assets.py --files $(assets) --header $$@, \
+  global \
+))

ion/src/simulator/linux/assets.py

@@ -1,5 +1,6 @@
-# This script generates a .s file representing assets in order to access
-# them from C code
+# This script generates:
+# - .s file representing assets in order to access them from C code
+# - .h representing the mapping between symbols and assets
 
 import sys
 import re
@@ -10,6 +11,7 @@ import os
 parser = argparse.ArgumentParser(description="Process some asset files.")
 parser.add_argument('--files', nargs='+', help='a list of file names')
 parser.add_argument('--implementation', help='the .s file to generate')
+parser.add_argument('--header', help='the .h file to generate')
 args = parser.parse_args()
 
 def print_asset(f, asset):
@@ -20,12 +22,39 @@ def print_asset(f, asset):
     f.write("    .incbin \"ion/src/simulator/assets/" + asset + "\"\n")
     f.write("_ion_simulator_" + asset_basename + "_end:\n\n")
 
-def print(files, path):
+def print_assembly(files, path):
     f = open(path, "w")
     for asset in files:
         print_asset(f, asset)
-
+        identifier += 1
     f.close()
 
-print(args.files, args.implementation)
+def print_declaration(f, asset):
+    asset_basename = os.path.splitext(asset)[0]
+    f.write("extern unsigned char _ion_simulator_" + asset_basename + "_start;\n")
+    f.write("extern unsigned char _ion_simulator_" + asset_basename + "_end;\n")
 
+def print_mapping(f, asset):
+    f.write('"' + asset + '", &_ion_simulator_' + asset_basename +'_start, &_ion_simulator_' + asset_basename '_end},\n')
+
+def print_header(files, path):
+    f = open(path, "w")
+    f.write("#ifndef ION_SIMULATOR_LINUX_IMAGES_H\n")
+    f.write("#define ION_SIMULATOR_LINUX_IMAGES_H\n\n")
+    f.write("// This file is auto-generated by assets.py\n\n")
+
+    for asset in files:
+        print_declaration(f, asset)
+
+    f.write("\nstatic struct { const char * identifier; unsigned char * start; unsigned char * end; } resources_addresses[] = {\n")
+    for asset in files:
+        print_mapping(f, asset)
+
+    f.write("};\n\n")
+    f.write("#endif\n")
+    f.close()
+
+if (args.implementation):
+    print_assembly(args.files, args.implementation)
+if (args.header):
+    print_header(args.files, args.implementation)

ion/src/simulator/linux/images.cpp

@@ -5,18 +5,7 @@
 #include <png.h>
 #include <assert.h>
 
-#ifndef ASSETS_ADDRESS_RANGES_DECLARATION
-#error Missing assets adress range declarations
-#endif
-
-ASSETS_ADDRESS_RANGES_DECLARATION
-static struct {
-  const char * identifier;
-  unsigned char * start;
-  unsigned char * end;
-} resources_addresses[] = {
-  ASSETS_ADDRESS_RANGES_DEFINITION
-};
+#include <ion/src/simulator/linux/images.h>
 
 enum class AssetFormat {
   JPG,