Add support for building the JS wrappers to the Makefile

Now that we have C and C++, we need to split the compile and link steps
(because we need different flags for the C and C++ files), so this is
easier with a Makefile.

Makefile

@@ -3,19 +3,38 @@
 BUILD_DIR := build
 OPTIMIZE_FLAGS ?= -g -O3
 TEST_OPTIMIZE_FLAGS ?= -g -O0
+JS_OPTIMIZE_FLAGS ?= -O3
 CC = gcc
+EMCC = emcc
 TARGET := $(BUILD_DIR)/libolm.so
+JS_TARGET := javascript/olm.js
+
+JS_EXPORTED_FUNCTIONS := javascript/exported_functions.json
+
+PUBLIC_HEADERS := include/olm/olm.hh
 
 SOURCES := $(wildcard src/*.cpp) $(wildcard src/*.c)
 OBJECTS := $(patsubst src/%,$(BUILD_DIR)/%,$(patsubst %.c,%.o,$(patsubst %.cpp,%.o,$(SOURCES))))
 TEST_SOURCES := $(wildcard tests/test_*.cpp) $(wildcard tests/test_*.c)
 TEST_BINARIES := $(patsubst tests/%,$(BUILD_DIR)/%,$(patsubst %.c,%,$(patsubst %.cpp,%,$(TEST_SOURCES))))
+JS_OBJECTS := $(patsubst %.o,%.js.bc,$(OBJECTS))
+JS_PRE := $(wildcard javascript/*pre.js)
+JS_POST := $(wildcard javascript/*post.js)
 
 CPPFLAGS += -Iinclude -Ilib
 CFLAGS += -Wall --std=c89 -fPIC
 CXXFLAGS += -Wall --std=c++11 -fPIC
 LDFLAGS += -Wall
 
+EMCCFLAGS = --closure 1 --memory-init-file 0 -s NO_FILESYSTEM=1 -s INVOKE_RUN=0
+# NO_BROWSER is kept for compatibility with emscripten 1.35.24, but is no
+# longer needed.
+EMCCFLAGS += -s NO_BROWSER=1
+
+EMCC.c = $(EMCC) $(CFLAGS) $(CPPFLAGS) -c
+EMCC.cc = $(EMCC) $(CXXFLAGS) $(CPPFLAGS) -c
+EMCC_LINK = $(EMCC) $(LDFLAGS) $(EMCCFLAGS)
+
 # generate .d files when compiling
 CPPFLAGS += -MMD
 
@@ -29,14 +48,29 @@ $(TEST_BINARIES): CPPFLAGS += -Itests/include
 $(TEST_BINARIES): LDLIBS += -lolm
 $(TEST_BINARIES): LDFLAGS += $(TEST_OPTIMIZE_FLAGS) -L$(BUILD_DIR)
 
+$(JS_OBJECTS): CFLAGS += $(JS_OPTIMIZE_FLAGS)
+$(JS_OBJECTS): CXXFLAGS += $(JS_OPTIMIZE_FLAGS)
+$(JS_TARGET): LDFLAGS += $(JS_OPTIMIZE_FLAGS)
+
 ### top-level targets
 
 $(TARGET): $(OBJECTS)
 	$(CXX) $(LDFLAGS) --shared -fPIC $^ $(OUTPUT_OPTION)
 
+js: $(JS_TARGET)
+.PHONY: js
+
+$(JS_TARGET): $(JS_OBJECTS) $(JS_PRE) $(JS_POST) $(JS_EXPORTED_FUNCTIONS)
+	$(EMCC_LINK) \
+	       --pre-js $(JS_PRE) --post-js $(JS_POST) \
+	       -s "EXPORTED_FUNCTIONS=@$(JS_EXPORTED_FUNCTIONS)" \
+               $(JS_OBJECTS) -o $@
+
 clean:;
 	rm -rf $(OBJECTS) $(OBJECTS:.o=.d) \
                $(TEST_BINARIES) $(TEST_BINARIES:=.d) \
+               $(JS_OBJECTS) $(JS_TARGET) \
+               $(JS_EXPORTED_FUNCTIONS) \
                $(TARGET)
 
 build_tests: $(TEST_BINARIES)
@@ -47,6 +81,10 @@ test: build_tests
 	    LD_LIBRARY_PATH=$(BUILD_DIR) $$i || exit $$?; \
 	done
 
+$(JS_EXPORTED_FUNCTIONS): $(PUBLIC_HEADERS)
+	perl -MJSON -ne '/(olm_[^( ]*)\(/ && push @f, "_$$1"; END { print encode_json \@f }' $^ > $@.tmp
+	mv $@.tmp $@
+
 ### rules for building objects
 $(BUILD_DIR)/%.o: src/%.c
 	$(COMPILE.c) $(OUTPUT_OPTION) $<
@@ -54,6 +92,12 @@ $(BUILD_DIR)/%.o: src/%.c
 $(BUILD_DIR)/%.o: src/%.cpp
 	$(COMPILE.cc) $(OUTPUT_OPTION) $<
 
+$(BUILD_DIR)/%.js.bc: src/%.c
+	$(EMCC.c) $(OUTPUT_OPTION) $<
+
+$(BUILD_DIR)/%.js.bc: src/%.cpp
+	$(EMCC.cc) $(OUTPUT_OPTION) $<
+
 $(BUILD_DIR)/%: tests/%.c
 	$(LINK.c) $< $(LOADLIBES) $(LDLIBS) -o $@
 
@@ -66,4 +110,5 @@ $(BUILD_DIR)/%: tests/%.cpp
 $(TEST_BINARIES): $(TARGET)
 
 -include $(OBJECTS:.o=.d)
+-include $(JS_OBJECTS:.bc=.d)
 -include $(TEST_BINARIES:=.d)

README.rst

@@ -26,7 +26,7 @@ To build the javascript bindings, install emscripten from http://kripken.github.
 
 .. code:: bash
 
-    javascript/build.py  # builds javascript/olm.js
+    make js
     npm pack javascript  # packages olm.js into olm-x.y.z.tgz
 
 Remember to make a tag after releasing a tarball:

javascript/build.py

@@ -1,74 +0,0 @@
-#! /usr/bin/env python
-# Copyright 2015 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-import subprocess
-import glob
-import os
-import sys
-import re
-import json
-
-
-os.chdir(os.path.dirname(os.path.dirname(os.path.realpath(__file__))))
-source_files = glob.glob("src/*.cpp")
-pre_js, = glob.glob("javascript/*pre.js")
-post_js, = glob.glob("javascript/*post.js")
-
-functions = set()
-RE_FUNCTION=re.compile("(olm_[^( ]*)\\(")
-with open("include/olm/olm.hh") as header:
-    for line in header:
-        match = RE_FUNCTION.search(line)
-        if match:
-            functions.add(match.groups()[0])
-
-
-exported_functions = os.path.abspath("javascript/exported_functions.json")
-with open(exported_functions, "w") as json_file:
-    json.dump(["_" + function for function in functions], json_file)
-
-
-emcc = os.environ.get("EMCC", "emcc")
-optimize_opts = os.environ.get("OPTIMIZE_FLAGS", "-O3")
-
-compile_args = [emcc]
-compile_args += optimize_opts.split()
-compile_args += ["-Wall"]
-compile_args += """
-    -Iinclude
-    -Ilib
-    -std=c++11
-    --closure 1
-    --memory-init-file 0
-    -s NO_FILESYSTEM=1
-    -s INVOKE_RUN=0
-""".split()
-# NO_BROWSER is kept for compatibility with emscripten 1.35.24, but is no
-# longer needed.
-compile_args += ("-s","NO_BROWSER=1")
-compile_args += source_files
-compile_args += ("--pre-js", pre_js)
-compile_args += ("--post-js", post_js)
-compile_args += ("-s", "EXPORTED_FUNCTIONS=@" + exported_functions)
-compile_args += sys.argv[1:]
-
-library = "javascript/olm.js"
-
-def run(args):
-    print args
-    print " ".join(args)
-    subprocess.check_call(args)
-
-run(compile_args + ["-o", library])

javascript/package.json

@@ -8,7 +8,7 @@
     "README.md"
   ],
   "scripts": {
-    "build": "./build.py",
+    "build": "make -C .. js",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "repository": {