From 643af145d355e6e30a32d3e529dc0f19e0082d40 Mon Sep 17 00:00:00 2001
From: James Roseborough <james.roseborough@luaj.org>
Date: Tue, 24 Mar 2009 22:44:07 +0000
Subject: [PATCH] Add debug hook functions to LuaState

---
 src/core/org/luaj/lib/DebugLib.java |  82 +++++++-------
 src/core/org/luaj/vm/Lua.java       |   1 -
 src/core/org/luaj/vm/LuaState.java  | 161 ++++++++++++++++++++++++++--
 src/test/res/debuglib.lua           |  40 +++++++
 version.properties                  |   2 +-
 5 files changed, 238 insertions(+), 48 deletions(-)
 create mode 100644 src/test/res/debuglib.lua

diff --git a/src/core/org/luaj/lib/DebugLib.java b/src/core/org/luaj/lib/DebugLib.java
index ca916a9c..ca945683 100644
--- a/src/core/org/luaj/lib/DebugLib.java
+++ b/src/core/org/luaj/lib/DebugLib.java
@@ -56,25 +56,23 @@ public class DebugLib extends LFunction {
 	private static final int DEBUG        	= 1;
 	private static final int GETFENV        = 2;
 	private static final int GETHOOK        = 3;
-	private static final int GETHOOKCOUNT   = 4;
-	private static final int GETHOOKMASK    = 5;
-	private static final int GETINFO        = 6;
-	private static final int GETLOCAL       = 7;
-	private static final int GETMETATABLE 	= 8;
-	private static final int GETREGISTRY    = 9;
-	private static final int GETUPVALUE    	= 10;
-	private static final int SETFENV        = 11;
-	private static final int SETHOOK        = 12;
-	private static final int SETLOCAL 		= 13;
-	private static final int SETMETATABLE   = 14;
-	private static final int SETUPVALUE    	= 15;
-	private static final int TRACEBACK    	= 16;
+	private static final int GETINFO        = 4;
+	private static final int GETLOCAL       = 5;
+	private static final int GETMETATABLE 	= 6;
+	private static final int GETREGISTRY    = 7;
+	private static final int GETUPVALUE    	= 8;
+	private static final int SETFENV        = 9;
+	private static final int SETHOOK        = 10;
+	private static final int SETLOCAL 		= 11;
+	private static final int SETMETATABLE   = 12;
+	private static final int SETUPVALUE    	= 13;
+	private static final int TRACEBACK    	= 14;
 	
-	public static void install( LTable globals ) {
+	public static void install( LuaState vm ) {
 		LTable debug = new LTable();
 		for (int i = 0; i < NAMES.length; i++)
 			debug.put(NAMES[i], new DebugLib(i + 1));
-		globals.put("debug", debug);
+		vm._G.put("debug", debug);
 		PackageLib.setIsLoaded("debug", debug);
 	}
 
@@ -91,7 +89,7 @@ public class DebugLib extends LFunction {
 	public boolean luaStackCall( LuaState vm ) {
 		switch ( id ) {
 		case INSTALL:
-			install(vm._G);
+			install(vm);
 			break;
 		case DEBUG: 
 			debug(vm);
@@ -102,12 +100,6 @@ public class DebugLib extends LFunction {
 		case GETHOOK: 
 			gethook(vm);
 			break;
-		case GETHOOKCOUNT: 
-			gethookcount(vm);
-			break;
-		case GETHOOKMASK: 
-			gethookmask(vm);
-			break;
 		case GETINFO: 
 			getinfo(vm);
 			break;
@@ -148,29 +140,37 @@ public class DebugLib extends LFunction {
 	}
 
 	private void debug(LuaState vm) {
-		// TODO Auto-generated method stub
+		// TODO: interactive console impl
 		vm.resettop();
 	}
 	
 	private void gethook(LuaState vm) {
-		// TODO Auto-generated method stub
+		LuaState threadVm = vm;
+		if ( vm.gettop() >= 2 )
+			threadVm = vm.checkthread(2).vm;
 		vm.resettop();
-	}
-
-	private void gethookcount(LuaState vm) {
-		// TODO Auto-generated method stub
-		vm.resettop();
-		vm.pushinteger(0);
-	}
-
-	private void gethookmask(LuaState vm) {
-		// TODO Auto-generated method stub
-		vm.resettop();
-		vm.pushinteger(0);
+		vm.pushlvalue(threadVm.gethook());
+		vm.pushinteger(threadVm.gethookmask());
+		vm.pushinteger(threadVm.gethookcount());
 	}
 
 	private void sethook(LuaState vm) {
-		// TODO Auto-generated method stub
+		LuaState threadVm = vm;
+		if ( vm.gettop() >= 4 ) {
+			threadVm = vm.checkthread(2).vm;
+			vm.remove(2);
+		}
+		LFunction func = vm.checkfunction(2);
+		LString str    = vm.checklstring(3);
+		int count      = vm.optint(4,0);
+		int mask       = 0;
+		for ( int i=0; i<str.m_length; i++ )
+			switch ( str.m_bytes[str.m_offset+i] ) {
+				case 'c': mask |= LuaState.LUA_MASKCALL; break;
+				case 'l': mask |= LuaState.LUA_MASKLINE; break;
+				case 'r': mask |= LuaState.LUA_MASKRET; break;
+			}
+		threadVm.sethook(func, mask, count);
 		vm.resettop();
 	}
 
@@ -213,7 +213,8 @@ public class DebugLib extends LFunction {
 		for (int i = 0, n = what.length(); i < n; i++) {
 			switch (what.charAt(i)) {
 				case 'S': {
-					info.put("source", (closure!=null? closure.p.source: new LString("?")));
+					info.put("source", (closure!=null? closure.p.source: new LString("@?")));
+					info.put("short_src", (closure!=null? closure.p.source.substring(1, closure.p.source.m_length-1): new LString("?")));
 					info.put("linedefined", (closure!=null? closure.p.linedefined: 0));
 					info.put("lastlinedefined", (closure!=null? closure.p.lastlinedefined: 0));
 					info.put("what", new LString(what));
@@ -235,12 +236,13 @@ public class DebugLib extends LFunction {
 					break;
 				}
 				case 'f': {
-					vm.pushlvalue( func!=null? func: LNil.NIL );
+					if ( func != null )
+						info.put( "func", func );
 					break;
 				}
 				case 'L': {
 					LTable lines = new LTable();
-					vm.pushlvalue(lines);
+					info.put("activelines", lines);
 					if ( closure != null )
 						for ( int j=0, k=1; j<closure.p.lineinfo.length; j++, k++ )
 							lines.put(k, LInteger.valueOf(closure.p.lineinfo[j]));
diff --git a/src/core/org/luaj/vm/Lua.java b/src/core/org/luaj/vm/Lua.java
index bed44326..40b906ef 100644
--- a/src/core/org/luaj/vm/Lua.java
+++ b/src/core/org/luaj/vm/Lua.java
@@ -356,6 +356,5 @@ public class Lua {
 		"thread",
 		"value",
 	};
-
 	
 }
diff --git a/src/core/org/luaj/vm/LuaState.java b/src/core/org/luaj/vm/LuaState.java
index e934eaa6..5c2bd86b 100644
--- a/src/core/org/luaj/vm/LuaState.java
+++ b/src/core/org/luaj/vm/LuaState.java
@@ -69,6 +69,7 @@ import org.luaj.lib.TableLib;
  * 
  */
 public class LuaState extends Lua {
+	
     /* thread status; 0 is OK */
     public static final int LUA_YIELD  = 1;
     public static final int LUA_ERRRUN = 2;
@@ -80,6 +81,16 @@ public class LuaState extends Lua {
     private static final int LUA_MINCALLS = 10;    
     private static final int MAXTAGLOOP	= 100;
 
+	// hook function values 
+	private static final int LUA_HOOKCALL = 0;
+	private static final int LUA_HOOKRET = 1;
+	private static final int LUA_HOOKLINE = 2;
+	private static final int LUA_HOOKCOUNT = 3;
+	private static final int LUA_HOOKTAILRET = 4;
+	public static final int LUA_MASKCALL = (1 << LUA_HOOKCALL);
+	public static final int LUA_MASKRET = (1 << LUA_HOOKRET);
+	public static final int LUA_MASKLINE = (1 << LUA_HOOKLINE);
+    
     public int base = 0;
     public int top = 0;
     protected int nresults = -1;
@@ -92,12 +103,16 @@ public class LuaState extends Lua {
 	static LuaState mainState;
     public LTable _G;
 
-    // main debug hook, overridden by DebugStackState
-    protected void debugHooks(int pc) {
-    }
-    protected void debugAssert(boolean b) {
-    }
+    // debug hooks - these MUST NOT be initialized, 
+	// so that a later obfuscation step can decide to remove them.
+	private boolean hooksenabled;
+    private int hookmask;
+    private int hookcount;
+    private LFunction hookfunc;
+    private int hookincr;
+    private int hookline;
     
+    protected void debugAssert(boolean b) {}
     
     // ------------------- constructors ---------------------
 	/**
@@ -525,7 +540,9 @@ public class LuaState extends Lua {
             ci.top = top;
         	
             // allow debug hooks a chance to operate
-            debugHooks( ci.pc );
+            if ( hooksenabled ) {
+            	debugBytecodeHooks( ci.pc );
+            }
             
             // advance program counter
             i = code[ci.pc++];
@@ -695,6 +712,11 @@ public class LuaState extends Lua {
                 // number of return values we need
                 c = LuaState.GETARG_C(i);
 
+                // call hook
+                if ( hooksenabled ) {
+                	debugCallHooks( ci.pc-1 );
+                }
+                
                 // make or set up the call
                 this.nresults = c - 1;
                 if (this.stack[base].luaStackCall(this))
@@ -713,6 +735,12 @@ public class LuaState extends Lua {
             }
             
             case LuaState.OP_TAILCALL: {
+                // return hook
+                if ( hooksenabled ) {
+                	debugTailReturnHooks( ci.pc-1 );
+                }
+
+                // close up values
                 closeUpVals(base);
 
                 // copy down the frame before calling!
@@ -755,6 +783,12 @@ public class LuaState extends Lua {
             }
 
             case LuaState.OP_RETURN: {
+                // return hook
+                if ( hooksenabled ) {
+                	debugReturnHooks( ci.pc-1 );
+                }
+
+                // close up values
                 closeUpVals( base ); 
 
                 // number of return vals to return
@@ -2326,4 +2360,119 @@ public class LuaState extends Lua {
         	top = oldtop;
         }
 	}
+
+	
+	// ===========================================================================
+	// Debug hooks.  
+	// These should be obfuscated out when sethook is never called 
+	// cannot be called from the application.
+	// 
+
+	/**
+	 * Set the hook function.    
+	 *   
+	 * @param func LFunction to call on the hook event
+	 * @param mask combination of LuaState.LUA_MASKLINE, LuaState.LUA_MASKCALL, and LuaState.LUA_MASKRET
+	 * @param count 0, or number of bytecodes between count events.
+	 */
+	public void sethook( LFunction func, int mask, int count ) {
+		hooksenabled = (mask != 0);
+		hookfunc = func;
+		hookmask = mask;
+		hookcount = count;
+	}
+	
+	/**
+	 *  Get the current hook function, if any. 
+	 * 
+	 * @return LFunction that is set as the current hook function, or null if not set.
+	 */
+	public LFunction gethook() {
+		return hookfunc;
+	}
+	
+	/**
+	 *  Get the current hook count. 
+	 * 
+	 * @return current count, which is # of bytecodes between "count" hook calls 
+	 */
+	public int gethookcount() {
+		return hookcount;
+	}
+	
+	/**
+	 *  Get the current hook mask. 
+	 * 
+	 * @return current mask as a combination of 
+	 * LuaState.LUA_MASKLINE, LuaState.LUA_MASKCALL, and LuaState.LUA_MASKRET
+	 */
+	public int gethookmask() {
+		return hookmask;
+	}
+	
+    // line number and count hooks
+    private void debugBytecodeHooks(int pc) {
+    	if ( hookfunc != null && (hookmask & LUA_MASKLINE) != 0 ) {
+        	int line = debugGetLineNumber(calls[cc]);
+        	if ( line != hookline ) {
+        		hookline = line;
+        		debugCallHook(LUA_HOOKLINE, line);
+        	}
+			if (hookcount != 0) {
+				if ( --hookincr <= 0 ) {
+					hookincr = hookcount;
+					debugCallHook(LUA_HOOKCOUNT, -1);
+				}
+			}
+		}
+    }
+    
+    private void debugCallHooks(int pc) {
+    	if ( hookfunc != null && ((hookmask & LUA_MASKCALL) != 0) ) {
+    		debugCallHook(LUA_HOOKCALL, debugGetLineNumber(calls[cc]));
+    		hookline = -1;
+    	}
+    }
+    
+    private void debugReturnHooks(int pc) {
+    	if ( hookfunc != null && ((hookmask & LUA_MASKRET) != 0) ) {
+    		debugCallHook(LUA_HOOKRET, debugGetLineNumber(calls[cc]));
+    		hookline = -1;
+    	}
+    }
+    
+    private void debugTailReturnHooks(int pc) {
+    	if ( hookfunc != null && ((hookmask & LUA_MASKRET) != 0) ) {
+    		debugCallHook(LUA_HOOKTAILRET, debugGetLineNumber(calls[cc]));
+    		hookline = -1;
+    	}
+    }
+    
+    private int debugGetLineNumber(CallInfo ci) {
+        int[] lineNumbers = ci.closure.p.lineinfo;
+        int pc = getCurrentPc(ci);
+        int line = (lineNumbers != null && lineNumbers.length > pc ? 
+                    lineNumbers[pc] :
+                    -1);
+        return line;
+    }
+		
+    private void debugCallHook(int mask, int newline) {
+    	int prevmask = hookmask;
+    	try {
+	    	hookmask = 0;
+	    	this.pushfunction(hookfunc);
+	    	switch ( mask ) {
+	    	default:              this.pushstring("line"); break;
+	    	case LUA_HOOKCOUNT:   this.pushstring("count"); break;
+	    	case LUA_HOOKCALL:    this.pushstring("call"); break;
+	    	case LUA_HOOKRET:     this.pushstring("return"); break;
+	    	case LUA_HOOKTAILRET: this.pushstring("tail return"); break;
+	    	}
+	    	this.pushinteger(newline);
+	    	this.pcall(2, 0, 0);
+    	} finally {
+    		hookmask = prevmask;
+    	}
+	}
 }
diff --git a/src/test/res/debuglib.lua b/src/test/res/debuglib.lua
new file mode 100644
index 00000000..da7727d3
--- /dev/null
+++ b/src/test/res/debuglib.lua
@@ -0,0 +1,40 @@
+
+local print = print
+print( 'has debug', debug~=nil )
+
+local printinfo = function(...)
+	for i,a in ipairs(arg) do
+		if type(a) == 'table' then
+			print( '   source: '..tostring(a.source) )
+			print( '   short_src: '..tostring(a.short_src) )
+			print( '   what: '..tostring(a.what) )
+			print( '   currentline: '..tostring(a.currentline) )
+			print( '   linedefined: '..tostring(a.linedefined) )
+			print( '   lastlinedefined: '..tostring(a.lastlinedefined) )
+		else
+			print( tostring(a) )
+		end
+	end
+end
+
+function test()
+	local x = 5
+	function f()
+		x = x + 1
+		return x
+	end
+	function g()
+		x = x - 1
+		return x
+	end
+	print(f())
+	print(g())
+	return f, g
+end
+
+local e,f,g = pcall( test )
+print( 'e,f,g', e, type(f), type(g) )
+
+printinfo( 'debug.getinfo(f,"Sl")', pcall(debug.getinfo, f, "Sl") ) 
+printinfo( 'debug.getinfo(g,"Sl")', pcall(debug.getinfo, g, "Sl") ) 
+printinfo( 'debug.getinfo(test,"Sl")', pcall(debug.getinfo, test, "Sl") )
diff --git a/version.properties b/version.properties
index 6715c53a..17ade615 100644
--- a/version.properties
+++ b/version.properties
@@ -1 +1 @@
-version: 0.92
+version: 0.93