Add "-q" flag for quiet operation

[cernekee]

It is very common to invoke assemblers or compilers from a scripted build (e.g. Makefile), and in that case it is desirable to avoid unnecessary console output so that warnings or errors are more apparent to the user. This patch adds a "-q" option to all three utilities for this purpose. Sample usage:

    OBJS := com/example/class_a.class \
            com/example/class_b.class \
            com/example/class_c.class

    $(OBJS): %.class: %.j
            @echo "  ASM    $@"
            @python assemble.py -q $<

    new.jar: $(OBJS)
            @echo "  JAR    $@"
            @jar cf $@ $^

This yields:

    $ make new.jar
      ASM    com/example/class_a.class
      ASM    com/example/class_b.class
      ASM    com/example/class_c.class
      JAR    new.jar
    $

[Storyyeller]

Can't you just redirect the output if you don't want it printed to the console?

[cernekee]

If I redirect all output, I won't see the warnings or errors.

If I am modifying the *.j source files by hand, it is likely that I'll introduce syntax errors at some point.

[Storyyeller]

Good point. I'll look at it later.

[Storyyeller]

Do you think this is only necessary for the assembler part? I can't imagine anyone invoking a decompiler from a makefile.

[cernekee]

Personally I'm only using it for the assembler right now. It might be useful for the disassembler if your workflow looks like:

• Disassemble a jar
• Patch/manipulate/deobfuscate the .j files
• Reassemble it back into a new jar

I believe there are a couple of Android APK/ROM auto-patchers that work this way (but they operate on smali, not Java bytecode).

It does seem unlikely that anyone would use the decompiler non-interactively.

[Storyyeller]

If you're editing bytecode by script, wouldn't you use a library instead? Text manipulation is pretty much the worst way to do it.

[cernekee]

Probably depends on the extent of the modification, and how much variation you expect in the input. There might also be situations where distributing/posting a patch is feasible, but distributing the jar file isn't.

In general I agree that using a library is preferable.

[Storyyeller]

I have added a -q option to the assembler in commit ba4acf6d7a05a381f83b2018af6b14553e31ad14.