debugger: Use libreadline for the prompt (#11)

* debugger: Use libreadline for the prompt

This fixes the issue where ^D would put the debugger into an infinite
loop, and adds support for persistent history, with familiar
keybindings.

I originally tried to make this new dependency optional, but your
usage of make doesn’t really tend itself to this, feel free to tell me
if you prefer another option.

Co-authored-by: Yannik Marchand <ymarchand@me.com>

Makefile

@@ -11,12 +11,12 @@ SRC += $(shell find src/ -type f -name "*.c")
 OBJS = $(patsubst src/%,build/%.o,$(SRC))
 
 main: $(OBJS)
-	$(CXX) -o $@ $(LDFLAGS) $(OBJS) -lcrypto
+	$(CXX) -o $@ $(LDFLAGS) $(OBJS) -lreadline -lhistory -lcrypto
 
 build/%.o: src/%
-	mkdir -p $(dir $@)
+	@mkdir -p $(dir $@)
 	$(CXX) $(SRCFLAGS) -c -o $@ $<
-	
+
 clean:
 	rm -rf build
 	rm -f main

src/debugger/debugger.cpp

@@ -3,10 +3,12 @@
 #include "debugger/expression.h"
 #include "debugger/common.h"
 #include "emulator.h"
+#include "history.h"
 
 #include "common/sys.h"
 #include "common/buffer.h"
 
+#include <readline/readline.h>
 #include <algorithm>
 
 
@@ -159,14 +161,21 @@ void Debugger::show(int core) {
 		DebugInterface *debugger = getInterface();
 		
 		std::string format = StringUtils::format("%%s:%s> ", debugger->format());
-		Sys::out->write(format, debugger->name(), debugger->pc());
+		std::string prompt = StringUtils::format(format, debugger->name(), debugger->pc());
 		
-		std::string line = Sys::in->readline();
-
 		std::vector<std::string> args;
 		
+		char *line = readline(prompt.c_str());
+		if (!line) {
+			ArgParser parser(debugger->getContext(), args);
+			quit(&parser);
+			return;
+		}
+		
+		History::append(line);
+		
 		std::string current;
-		for (char c : line) {
+		for (char c : std::string(line)) {
 			if (c == ' ') {
 				if (!current.empty()) {
 					args.push_back(current);

src/history.cpp

@@ -0,0 +1,33 @@
+
+#include "history.h"
+
+#include <readline/history.h>
+#include <sys/stat.h>
+#include <cstdlib>
+
+
+namespace History {
+	std::string filename;
+
+	void init() {
+		using_history();
+		
+		char *home = getenv("HOME");
+		char *xdg_data = getenv("XDG_DATA_HOME");
+		
+		std::string directory;
+		if (xdg_data && xdg_data[0] == '/')
+			directory = std::string(xdg_data) + "/wiiu-firmware-emulator";
+		else
+			directory = std::string(home) + "/.local/share/wiiu-firmware-emulator";
+	
+		mkdir(directory.c_str(), 0755);
+		filename = directory + "/history";
+		read_history(filename.c_str());
+	}
+
+	void append(char *line) {
+		add_history(line);
+		write_history(filename.c_str());
+	}
+}

src/history.h

@@ -0,0 +1,9 @@
+
+#pragma once
+
+#include <string>
+
+namespace History {
+	void init();
+	void append(char *line);
+}

src/main.cpp

@@ -1,10 +1,12 @@
 
 #include "emulator.h"
+#include "history.h"
 #include "common/logger.h"
 
 int main(int argc, const char *argv[]) {
 	Logger::init(Logger::DEBUG);
-	
+	History::init();
+
 	Emulator *emulator = new Emulator();
 	emulator->run();
 	delete emulator;