Better Java integration

Makefile

@@ -1,5 +1,4 @@
 OPENCL_LIB ?= /usr/local/cuda-9.1/lib64
-OPENJDK_PATH ?= $(shell readlink -f /usr/bin/javac | sed "s:bin/javac::")
 SRC ?= ./src
 OUT ?= ./build
 DISABLE_GPU ?= 1
@@ -24,18 +23,7 @@ PYFLAGS += 0
 endif
 
 ifneq ("$(DISABLE_JNI)","1")
-UNAME_S := $(shell uname -s)
-ifeq ($(UNAME_S),Darwin)
-JAVA_HOME := $(shell /usr/libexec/java_home)
-CFLAGS_JNI = \
-	-I$(JAVA_HOME)/include \
-	-I$(JAVA_HOME)/include/darwin
-else
-# Default to Linux
-CFLAGS_JNI = \
-	-I$(OPENJDK_PATH)/include \
-	-I$(OPENJDK_PATH)/include/linux
-endif
+include mk/java.mk
 endif
 
 TESTS = \
@@ -54,6 +42,7 @@ LIBS = libdcurl.so
 LIBS := $(addprefix $(OUT)/, $(LIBS))
 
 all: $(TESTS) $(LIBS)
+.DEFAULT_GOAL := all
 
 OBJS = \
 	hash/curl.o \
@@ -87,10 +76,6 @@ $(OUT)/test_%.o: test/test_%.c
 	$(VECHO) "  CC\t$@\n"
 	$(Q)$(CC) -o $@ $(CFLAGS) -c -MMD -MF $@.d $<
 
-$(OUT)/jni/%.o: jni/%.c
-	$(VECHO) "  CC\t$@\n"
-	$(Q)$(CC) -o $@ $(CFLAGS) $(CFLAGS_JNI) -c -MMD -MF $@.d $<
-
 $(OUT)/trinary/%.o: $(SRC)/trinary/%.c
 $(OUT)/hash/%.o: $(SRC)/hash/%.c
 $(OUT)/%.o: $(SRC)/%.c

README.md

@@ -8,7 +8,8 @@ Reference Implementation (IRI).
 
 # Warning
 * You need to configure OpenCL platform and device by yourself in ```src/clcontext.c```
-* You also need to configure path of OpenCL Library and OpenJDK in ```Makefile```
+* You need to configure paths and flags of OpenCL installation in ```Makefile```
+* Check JDK installation and set JAVA_HOME if you wish to specify.
 * Only one GPU can be facilitated with dcurl at the moment.
 
 # Build

mk/java.mk

@@ -0,0 +1,61 @@
+UNAME_S := $(shell uname -s)
+
+# if JAVA_HOME is not set, guess it according to system configurations
+ifndef JAVA_HOME
+ifeq ($(UNAME_S),Darwin)
+    # macOS
+    JAVA_HOME := $(shell /usr/libexec/java_home)
+else
+# Default to Linux
+    JAVAC := $(shell which javac)
+    ifndef JAVAC
+    $(error "javac is not available. Please check JDK installation")
+    endif
+    JAVA_HOME := $(shell readlink -f $(JAVAC) | sed "s:bin/javac::")
+endif
+endif # JAVA_HOME
+
+JAVAH = javah
+ifdef JAVA_HOME
+JAVAH = $(JAVA_HOME)/bin/javah
+endif
+JAVAH := $(shell which $(JAVAH))
+ifndef JAVAH
+$(error "javah is not available. Please check JDK installation")
+endif
+
+CURL := $(shell which curl)
+ifndef CURL
+$(error "curl is not available.")
+endif
+
+SHELL_HACK := $(shell mkdir -p $(OUT)/com/iota/iri/hash)
+
+GITHUB_REPO ?= chenwei-tw/iri/feat/new_pow_interface
+PearlDriverSRC := src/main/java/com/iota/iri/hash/PearlDiver.java
+
+$(OUT)/com/iota/iri/hash/PearlDiver.java: $(OUT)/com/iota/iri/hash
+	$(VECHO) "  CURL\t$@\n"
+	$(Q)$(CURL) -s -o $@ \
+	"https://github.com/raw/$(GITHUB_REPO)/$(PearlDriverSRC)"
+
+$(OUT)/jni/iri-pearldiver-exlib.h: $(OUT)/com/iota/iri/hash/PearlDiver.java
+	$(VECHO) "  JAVAH\t$@\n"
+	$(Q)$(JAVAH) -classpath $(OUT) -o $@ com.iota.iri.hash.PearlDiver
+
+ifeq ($(UNAME_S),Darwin)
+    # macOS
+    CFLAGS_JNI := -I$(JAVA_HOME)/include/darwin
+else
+    # Default to Linux
+    CFLAGS_JNI := -I$(JAVA_HOME)/include/linux
+endif
+
+CFLAGS_JNI += -I$(JAVA_HOME)/include
+CFLAGS_JNI += -I$(OUT)/jni
+
+jni/iri-pearldiver-exlib.c: $(OUT)/jni/iri-pearldiver-exlib.h
+
+$(OUT)/jni/%.o: jni/%.c
+	$(VECHO) "  CC\t$@\n"
+	$(Q)$(CC) -o $@ $(CFLAGS) $(CFLAGS_JNI) -c -MMD -MF $@.d $<