From f55e7834ba8b89cdca452ca8cb83299c7a890149 Mon Sep 17 00:00:00 2001
From: Robert Xiao <brx@cs.ubc.ca>
Date: Thu, 6 Jul 2023 20:12:36 -0700
Subject: [PATCH] Replace javah by javac -h, only write new constant files if
 something changes.

The const_generator changes help to ensure that e.g. Java rebuilds don't keep
rebuilding everything.
---
 bindings/const_generator.py | 18 ++++++++++++++++--
 bindings/java/.gitignore    |  1 -
 bindings/java/Makefile      |  8 ++------
 bindings/java/pom.xml       |  6 ++++++
 4 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/bindings/const_generator.py b/bindings/const_generator.py
index 40e02048..982b48f4 100644
--- a/bindings/const_generator.py
+++ b/bindings/const_generator.py
@@ -159,8 +159,9 @@ def gen(lang):
     templ = template[lang]
     for target in include:
         prefix = templ[target]
-        outfile = open(templ['out_file'] %(prefix), 'wb')   # open as binary prevents windows newlines
-        outfile.write((templ['header'] % (prefix)).encode("utf-8"))
+        outfn = templ['out_file'] % prefix
+        outfile = open(outfn + ".tmp", 'wb')   # open as binary prevents windows newlines
+        outfile.write((templ['header'] % prefix).encode("utf-8"))
         if target == 'unicorn.h':
             prefix = ''
         with open(os.path.join(INCL_DIR, target)) as f:
@@ -278,6 +279,19 @@ def gen(lang):
         outfile.write((templ['footer']).encode("utf-8"))
         outfile.close()
 
+        if os.path.isfile(outfn):
+            with open(outfn, "rb") as infile:
+                cur_data = infile.read()
+            with open(outfn + ".tmp", "rb") as infile:
+                new_data = infile.read()
+            if cur_data == new_data:
+                os.unlink(outfn + ".tmp")
+            else:
+                os.unlink(outfn)
+                os.rename(outfn + ".tmp", outfn)
+        else:
+            os.rename(outfn + ".tmp", outfn)
+
 def main():
     lang = sys.argv[1]
     if lang == "all":
diff --git a/bindings/java/.gitignore b/bindings/java/.gitignore
index b2a1df87..2f7896d1 100644
--- a/bindings/java/.gitignore
+++ b/bindings/java/.gitignore
@@ -1,2 +1 @@
 target/
-unicorn_Unicorn.h
diff --git a/bindings/java/Makefile b/bindings/java/Makefile
index 9dae6098..aa3fe7d1 100644
--- a/bindings/java/Makefile
+++ b/bindings/java/Makefile
@@ -26,14 +26,11 @@ CFLAGS=-fPIC
 LDFLAGS=-shared -fPIC
 # May also use -lunicorn to dynamically link against the installed unicorn
 LIBS=../../build/libunicorn.a
-INCS=-I$(JAVA_INC) -I$(JAVA_PLATFORM_INC) -I$(UNICORN_INC)
+INCS=-I target/headers -I$(JAVA_INC) -I$(JAVA_PLATFORM_INC) -I$(UNICORN_INC)
 
 OBJS=unicorn_Unicorn.o
 
-unicorn_Unicorn.h: src/main/java/unicorn/Unicorn.java
-	javah -cp src/main/java -o $@ unicorn.Unicorn
-
-unicorn_Unicorn.o: unicorn_Unicorn.c unicorn_Unicorn.h
+unicorn_Unicorn.o: unicorn_Unicorn.c target/headers/unicorn_Unicorn.h
 	$(CC) -O2 -Wall -Wextra -Wno-unused-parameter -c $(CFLAGS) $(INCS) $< -o $@
 
 libunicorn_java$(LIB_EXT): $(OBJS)
@@ -41,7 +38,6 @@ libunicorn_java$(LIB_EXT): $(OBJS)
 
 clean:
 	rm -f libunicorn_java$(LIB_EXT)
-	rm -f unicorn_Unicorn.h
 	rm -f $(OBJS)
 
 .PHONY: all clean
diff --git a/bindings/java/pom.xml b/bindings/java/pom.xml
index fa5da8f2..686f7b66 100644
--- a/bindings/java/pom.xml
+++ b/bindings/java/pom.xml
@@ -33,6 +33,12 @@
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-compiler-plugin</artifactId>
           <version>3.11.0</version>
+          <configuration>
+            <compilerArgs>
+              <arg>-h</arg>
+              <arg>target/headers</arg>
+             </compilerArgs>
+          </configuration>
         </plugin>
       </plugins>
     </pluginManagement>