add dumpops.lua as a sample scraper that just dumps the arguments

src/utils/SkLuaCanvas.cpp

Index: src/utils/SkLuaCanvas.cpp
diff --git a/src/utils/SkLuaCanvas.cpp b/src/utils/SkLuaCanvas.cpp
index e13073aea9fb30b2deccd9b6aa46ba415014e2f3..be6cb6624a751ff3ae60f6111b68b74a927395dc 100644
--- a/src/utils/SkLuaCanvas.cpp
+++ b/src/utils/SkLuaCanvas.cpp
@@ -6,117 +6,16 @@
  */
 
 #include "SkLuaCanvas.h"
-#include "SkRRect.h"
+#include "SkLua.h"
 
 extern "C" {
     #include "lua.h"
     #include "lauxlib.h"
 }
 
-static void setfield_string(lua_State* L, const char key[], const char value[]) {
-    lua_pushstring(L, value);
-    lua_setfield(L, -2, key);
-}
-
-static void setfield_number(lua_State* L, const char key[], double value) {
-    lua_pushnumber(L, value);
-    lua_setfield(L, -2, key);
-}
-
-static void setfield_bool(lua_State* L, const char key[], bool value) {
-    lua_pushboolean(L, value);
-    lua_setfield(L, -2, key);
-}
-
-// sets [1]...[count] in the table on the top of the stack
-static void setfield_arrayf(lua_State* L, const SkScalar array[], int count) {
-    for (int i = 0; i < count; ++i) {
-        lua_pushnumber(L, SkScalarToDouble(i + 1));     // key
-        lua_pushnumber(L, SkScalarToDouble(array[i]));  // value
-        lua_settable(L, -3);
-    }
-}
-
-static void push_rect(lua_State* L, const SkRect& r) {
-    lua_newtable(L);
-    setfield_number(L, "left", r.fLeft);
-    setfield_number(L, "top", r.fTop);
-    setfield_number(L, "right", r.fRight);
-    setfield_number(L, "bottom", r.fBottom);
-}
-
-static void setfield_rect(lua_State* L, const char key[], const SkRect& r) {
-    push_rect(L, r);
-    lua_setfield(L, -2, key);
-}
-
-static const char* rrect_type(const SkRRect& rr) {
-    switch (rr.getType()) {
-        case SkRRect::kUnknown_Type: return "unknown";
-        case SkRRect::kEmpty_Type: return "empty";
-        case SkRRect::kRect_Type: return "rect";
-        case SkRRect::kOval_Type: return "oval";
-        case SkRRect::kSimple_Type: return "simple";
-        case SkRRect::kComplex_Type: return "complex";
-    }
-    SkASSERT(!"never get here");
-    return "";
-}
-
-static void setfield_rrect(lua_State* L, const char key[], const SkRRect& rr) {
-    lua_newtable(L);
-    setfield_rect(L, "rect", rr.getBounds());
-    setfield_string(L, "type", rrect_type(rr));
-
-    SkVector rad[4] = {
-        rr.radii(SkRRect::kUpperLeft_Corner),
-        rr.radii(SkRRect::kUpperRight_Corner),
-        rr.radii(SkRRect::kLowerRight_Corner),
-        rr.radii(SkRRect::kLowerLeft_Corner),
-    };
-    setfield_arrayf(L, &rad[0].fX, 8);
-    lua_setfield(L, -2, key);
-}
-
-static void push_matrix(lua_State* L, const SkMatrix& mat) {
-    SkScalar m[9];
-    for (int i = 0; i < 9; ++i) {
-        m[i] = mat[i];
-    }
-    lua_newtable(L);
-    setfield_arrayf(L, m, 9);
-}
-
-enum PaintUsage {
-    kText_PaintUsage,
-    kImage_PaintUsage,
-    kGeometry_PaintUsage
-};
-
-static const char* color2string(SkColor c, SkString* str) {
-    str->printf("0x%08X", c);
-    return str->c_str();
-}
-
-static void setfield_paint(lua_State* L, const SkPaint& p,
-                           PaintUsage pu = kGeometry_PaintUsage) {
-    SkString str;
-
-    lua_newtable(L);
-    setfield_bool(L, "aa", p.isAntiAlias());
-    setfield_string(L, "color", color2string(p.getColor(), &str));
-
-    if (kGeometry_PaintUsage == pu) {
-        if (SkPaint::kFill_Style != p.getStyle()) {
-            setfield_number(L, "stroke-width", p.getStrokeWidth());
-        }
-    }
-    lua_setfield(L, -2, "paint");
-}
-
-class AutoCallLua {
+class AutoCallLua : public SkLua {
 public:
-    AutoCallLua(lua_State* L, const char func[], const char verb[]) : fL(L) {
+    AutoCallLua(lua_State* L, const char func[], const char verb[]) : INHERITED(L) {
         lua_getglobal(L, func);
         if (!lua_isfunction(L, -1)) {
             int t = lua_type(L, -1);
@@ -124,177 +23,27 @@ public:
         }
 
         lua_newtable(L);
-        setfield_string(L, "verb", verb);
+        this->pushString(verb, "verb");
     }
 
     ~AutoCallLua() {
-        if (lua_pcall(fL, 1, 0, 0) != LUA_OK) {
-            SkDebugf("lua err: %s\n", lua_tostring(fL, -1));
+        lua_State* L = this->getL();
+        if (lua_pcall(L, 1, 0, 0) != LUA_OK) {
+            SkDebugf("lua err: %s\n", lua_tostring(L, -1));
         }
-        lua_settop(fL, -1);
+        lua_settop(L, -1);
     }
 
 private:
-    lua_State* fL;
-};
-
-#define AUTO_LUA(verb)  AutoCallLua acl(fL, fFunc.c_str(), verb)
-
-///////////////////////////////////////////////////////////////////////////////
-
-static const char gCanvasMetaTableName[] = "SkCanvas_MetaTable";
-
-static int lcanvas_getSaveCount(lua_State* L) {
-    SkCanvas* c = *(SkCanvas**)luaL_checkudata(L, 1, gCanvasMetaTableName);
-    lua_pushnumber(L, (double)c->getSaveCount());
-    return 1;
-}
-
-static int lcanvas_getTotalMatrix(lua_State* L) {
-    SkCanvas* c = *(SkCanvas**)luaL_checkudata(L, 1, gCanvasMetaTableName);
-    push_matrix(L, c->getTotalMatrix());
-    return 1;
-}
-
-static int lcanvas_gc(lua_State* L) {
-    SkCanvas** cptr = (SkCanvas**)luaL_checkudata(L, 1, gCanvasMetaTableName);
-    SkSafeUnref(*cptr);
-    *cptr = NULL;
-    return 0;
-}
-
-static const struct luaL_Reg gLuaCanvasMethods[] = {
-    { "getSaveCount", lcanvas_getSaveCount },
-    { "getTotalMatrix", lcanvas_getTotalMatrix },
-    { "__gc", lcanvas_gc },
-    { NULL, NULL }
-};
-
-static void ensure_canvas_metatable(lua_State* L) {
-    static bool gOnce;
-    if (gOnce) {
-        return;
-    }
-    gOnce = true;
-
-    luaL_newmetatable(L, gCanvasMetaTableName);
-    lua_pushvalue(L, -1);
-    lua_setfield(L, -2, "__index");
-
-    luaL_setfuncs(L, gLuaCanvasMethods, 0);
-    lua_settop(L, -2);  // pop off the meta-table
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-static const char gPathMetaTableName[] = "SkPath_MetaTable";
-
-static int lpath_getBounds(lua_State* L) {
-    SkPath* p = (SkPath*)luaL_checkudata(L, 1, gPathMetaTableName);
-    push_rect(L, p->getBounds());
-    return 1;
-}
-
-static int lpath_isEmpty(lua_State* L) {
-    SkPath* p = (SkPath*)luaL_checkudata(L, 1, gPathMetaTableName);
-    lua_pushboolean(L, p->isEmpty());
-    return 1;
-}
-
-static int lpath_isRect(lua_State* L) {
-    SkPath* p = (SkPath*)luaL_checkudata(L, 1, gPathMetaTableName);
-    SkRect r;
-    bool pred = p->isRect(&r);
-    int ret_count = 1;
-    lua_pushboolean(L, pred);
-    if (pred) {
-        push_rect(L, r);
-        ret_count += 1;
-    }
-    return ret_count;
-}
-
-static const char* dir2string(SkPath::Direction dir) {
-    static const char* gStr[] = {
-        "unknown", "cw", "ccw"
-    };
-    SkASSERT((unsigned)dir < SK_ARRAY_COUNT(gStr));
-    return gStr[dir];
-}
-
-static int lpath_isNestedRects(lua_State* L) {
-    SkPath* p = (SkPath*)luaL_checkudata(L, 1, gPathMetaTableName);
-    SkRect rects[2];
-    SkPath::Direction dirs[2];
-    bool pred = p->isNestedRects(rects, dirs);
-    int ret_count = 1;
-    lua_pushboolean(L, pred);
-    if (pred) {
-        push_rect(L, rects[0]);
-        push_rect(L, rects[1]);
-        lua_pushstring(L, dir2string(dirs[0]));
-        lua_pushstring(L, dir2string(dirs[0]));
-        ret_count += 4;
-    }
-    return ret_count;
-}
-
-static int lpath_gc(lua_State* L) {
-    SkPath* p = (SkPath*)luaL_checkudata(L, 1, gPathMetaTableName);
-    p->~SkPath();
-    return 0;
-}
-
-static const struct luaL_Reg gLuaPathMethods[] = {
-    { "getBounds", lpath_getBounds },
-    { "isEmpty", lpath_isEmpty },
-    { "isRect", lpath_isRect },
-    { "isNestedRects", lpath_isNestedRects },
-    { "__gc", lpath_gc },
-    { NULL, NULL }
+    typedef SkLua INHERITED;
 };
 
-static void ensure_path_metatable(lua_State* L) {
-    static bool gOnce;
-    if (gOnce) {
-        return;
-    }
-    gOnce = true;
-
-    luaL_newmetatable(L, gPathMetaTableName);
-    lua_pushvalue(L, -1);
-    lua_setfield(L, -2, "__index");
-
-    luaL_setfuncs(L, gLuaPathMethods, 0);
-    lua_settop(L, -2);  // pop off the meta-table
-}
-
-static void push_path(lua_State* L, const SkPath& src) {
-    ensure_path_metatable(L);
-
-    SkPath* path = (SkPath*)lua_newuserdata(L, sizeof(SkPath));
-    new (path) SkPath(src);
-
-    luaL_getmetatable(L, gPathMetaTableName);
-    lua_setmetatable(L, -2);
-}
-
-static void setfield_path(lua_State* L, const char key[], const SkPath& path) {
-    push_path(L, path);
-    lua_setfield(L, -2, key);
-}
+#define AUTO_LUA(verb)  AutoCallLua lua(fL, fFunc.c_str(), verb)
 
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkLuaCanvas::pushThis() {
-    ensure_canvas_metatable(fL);
-
-    SkCanvas** canvasPtr = (SkCanvas**)lua_newuserdata(fL, sizeof(SkCanvas*));
-    luaL_getmetatable(fL, gCanvasMetaTableName);
-    lua_setmetatable(fL, -2);
-
-    this->ref();
-    *canvasPtr = this;
+    SkLua(fL).pushCanvas(this);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -322,10 +71,10 @@ int SkLuaCanvas::saveLayer(const SkRect* bounds, const SkPaint* paint,
                              SaveFlags flags) {
     AUTO_LUA("saveLayer");
     if (bounds) {
-        setfield_rect(fL, "bounds", *bounds);
+        lua.pushRect(*bounds, "bounds");
     }
     if (paint) {
-        setfield_paint(fL, *paint);
+        lua.pushPaint(*paint, "paint");
     }
     return this->INHERITED::save(flags);
 }
@@ -337,29 +86,29 @@ void SkLuaCanvas::restore() {
 
 bool SkLuaCanvas::translate(SkScalar dx, SkScalar dy) {
     AUTO_LUA("translate");
-    setfield_number(fL, "dx", dx);
-    setfield_number(fL, "dy", dy);
+    lua.pushScalar(dx, "dx");
+    lua.pushScalar(dy, "dy");
     return this->INHERITED::translate(dx, dy);
 }
 
 bool SkLuaCanvas::scale(SkScalar sx, SkScalar sy) {
     AUTO_LUA("scale");
-    setfield_number(fL, "sx", sx);
-    setfield_number(fL, "sy", sy);
+    lua.pushScalar(sx, "sx");
+    lua.pushScalar(sy, "sy");
     return this->INHERITED::scale(sx, sy);
 }
 
 bool SkLuaCanvas::rotate(SkScalar degrees) {
     AUTO_LUA("rotate");
-    setfield_number(fL, "degrees", degrees);
+    lua.pushScalar(degrees, "degrees");
     return this->INHERITED::rotate(degrees);
 }
 
-bool SkLuaCanvas::skew(SkScalar sx, SkScalar sy) {
+bool SkLuaCanvas::skew(SkScalar kx, SkScalar ky) {
     AUTO_LUA("skew");
-    setfield_number(fL, "sx", sx);
-    setfield_number(fL, "sy", sy);
-    return this->INHERITED::skew(sx, sy);
+    lua.pushScalar(kx, "kx");
+    lua.pushScalar(ky, "ky");
+    return this->INHERITED::skew(kx, ky);
 }
 
 bool SkLuaCanvas::concat(const SkMatrix& matrix) {
@@ -373,22 +122,22 @@ void SkLuaCanvas::setMatrix(const SkMatrix& matrix) {
 
 bool SkLuaCanvas::clipRect(const SkRect& r, SkRegion::Op op, bool doAA) {
     AUTO_LUA("clipRect");
-    setfield_rect(fL, "rect", r);
-    setfield_bool(fL, "aa", doAA);
+    lua.pushRect(r, "rect");
+    lua.pushBool(doAA, "aa");
     return this->INHERITED::clipRect(r, op, doAA);
 }
 
 bool SkLuaCanvas::clipRRect(const SkRRect& rrect, SkRegion::Op op, bool doAA) {
     AUTO_LUA("clipRRect");
-    setfield_rrect(fL, "rrect", rrect);
-    setfield_bool(fL, "aa", doAA);
+    lua.pushRRect(rrect, "rrect");
+    lua.pushBool(doAA, "aa");
     return this->INHERITED::clipRRect(rrect, op, doAA);
 }
 
 bool SkLuaCanvas::clipPath(const SkPath& path, SkRegion::Op op, bool doAA) {
     AUTO_LUA("clipPath");
-    setfield_path(fL, "path", path);
-    setfield_bool(fL, "aa", doAA);
+    lua.pushPath(path, "path");
+    lua.pushBool(doAA, "aa");
     return this->INHERITED::clipPath(path, op, doAA);
 }
 
@@ -399,44 +148,44 @@ bool SkLuaCanvas::clipRegion(const SkRegion& deviceRgn, SkRegion::Op op) {
 
 void SkLuaCanvas::drawPaint(const SkPaint& paint) {
     AUTO_LUA("drawPaint");
-    setfield_paint(fL, paint);
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawPoints(PointMode mode, size_t count,
                                const SkPoint pts[], const SkPaint& paint) {
     AUTO_LUA("drawPoints");
-    setfield_paint(fL, paint);
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawOval(const SkRect& rect, const SkPaint& paint) {
     AUTO_LUA("drawOval");
-    setfield_rect(fL, "oval", rect);
-    setfield_paint(fL, paint);
+    lua.pushRect(rect, "rect");
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawRect(const SkRect& rect, const SkPaint& paint) {
     AUTO_LUA("drawRect");
-    setfield_rect(fL, "rect", rect);
-    setfield_paint(fL, paint);
+    lua.pushRect(rect, "rect");
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawRRect(const SkRRect& rrect, const SkPaint& paint) {
     AUTO_LUA("drawRRect");
-    setfield_rrect(fL, "rrect", rrect);
-    setfield_paint(fL, paint);
+    lua.pushRRect(rrect, "rrect");
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawPath(const SkPath& path, const SkPaint& paint) {
     AUTO_LUA("drawPath");
-    setfield_path(fL, "path", path);
-    setfield_paint(fL, paint);
+    lua.pushPath(path, "path");
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawBitmap(const SkBitmap& bitmap, SkScalar x, SkScalar y,
                                const SkPaint* paint) {
     AUTO_LUA("drawBitmap");
     if (paint) {
-        setfield_paint(fL, *paint, kImage_PaintUsage);
+        lua.pushPaint(*paint, "paint");
     }
 }
 
@@ -444,7 +193,7 @@ void SkLuaCanvas::drawBitmapRectToRect(const SkBitmap& bitmap, const SkRect* src
                                    const SkRect& dst, const SkPaint* paint) {
     AUTO_LUA("drawBitmapRectToRect");
     if (paint) {
-        setfield_paint(fL, *paint, kImage_PaintUsage);
+        lua.pushPaint(*paint, "paint");
     }
 }
 
@@ -452,7 +201,7 @@ void SkLuaCanvas::drawBitmapMatrix(const SkBitmap& bitmap, const SkMatrix& m,
                                      const SkPaint* paint) {
     AUTO_LUA("drawBitmapMatrix");
     if (paint) {
-        setfield_paint(fL, *paint, kImage_PaintUsage);
+        lua.pushPaint(*paint, "paint");
     }
 }
 
@@ -460,35 +209,35 @@ void SkLuaCanvas::drawSprite(const SkBitmap& bitmap, int x, int y,
                                const SkPaint* paint) {
     AUTO_LUA("drawSprite");
     if (paint) {
-        setfield_paint(fL, *paint, kImage_PaintUsage);
+        lua.pushPaint(*paint, "paint");
     }
 }
 
 void SkLuaCanvas::drawText(const void* text, size_t byteLength, SkScalar x,
                              SkScalar y, const SkPaint& paint) {
     AUTO_LUA("drawText");
-    setfield_paint(fL, paint, kText_PaintUsage);
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawPosText(const void* text, size_t byteLength,
                                 const SkPoint pos[], const SkPaint& paint) {
     AUTO_LUA("drawPosText");
-    setfield_paint(fL, paint, kText_PaintUsage);
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawPosTextH(const void* text, size_t byteLength,
                                  const SkScalar xpos[], SkScalar constY,
                                  const SkPaint& paint) {
     AUTO_LUA("drawPosTextH");
-    setfield_paint(fL, paint, kText_PaintUsage);
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawTextOnPath(const void* text, size_t byteLength,
                                    const SkPath& path, const SkMatrix* matrix,
                                    const SkPaint& paint) {
     AUTO_LUA("drawTextOnPath");
-    setfield_path(fL, "path", path);
-    setfield_paint(fL, paint, kText_PaintUsage);
+    lua.pushPath(path, "path");
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawPicture(SkPicture& picture) {
@@ -503,7 +252,7 @@ void SkLuaCanvas::drawVertices(VertexMode vmode, int vertexCount,
                                  const uint16_t indices[], int indexCount,
                                  const SkPaint& paint) {
     AUTO_LUA("drawVertices");
-    setfield_paint(fL, paint);
+    lua.pushPaint(paint, "paint");
 }
 
 void SkLuaCanvas::drawData(const void* data, size_t length) {