Version 12 (modified by 12 years ago) ( diff ) | ,
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Summary
- EFL port should adhere to the WebKit Coding Style basically.(http://www.webkit.org/coding/coding-style.html)
- Do not use abbreviation except for public APIs
- Do not use Eina_Bool type except for public APIs
- Place '*' operator to data type
- Use C++ casting for type casting. For example, static_cast<...>, const_cast<...>, reinterpret_cast<...>
- Use smart pointers
- Use c++ new/delete operators
- Use const keyword instead of #define when you define constant variable.
- Use NULL in public C headers instead of 0
- Use a double negation (!!) when you modify or compare with a Eina Bool member variable which stores a value in a bit field.
Example
Do not use abbreviation except for public APIs
Public APIs
EAPI void ewk_view_bg_color_set(Evas_Object *o, int r, int g, int b, int a);
Implementation
void ewk_view_bg_color_set(Evas_Object* ewkView, int red, int green, int blue, int alpha) { EWK_VIEW_SD_GET_OR_RETURN(ewkView, smartData); EINA_SAFETY_ON_NULL_RETURN(smartData->api); EINA_SAFETY_ON_NULL_RETURN(smartData->api->bg_color_set); if (alpha < 0) { WRN("Alpha less than zero (%d).", alpha); alpha = 0; } else if (alpha > 255) { WRN("Alpha is larger than 255 (%d).", alpha); alpha = 255; } ... }
Do not use Eina_Bool type except for public APIs
Public APIs
EAPI Eina_Bool ewk_view_scale_set(Evas_Object *o, float scale_factor, Evas_Coord cx, Evas_Coord cy);
Implementation
Eina_Bool ewk_view_scale_set(Evas_Object* ewkView, float scaleFactor, Evas_Coord centerX, Evas_Coord centerY) { EWK_VIEW_SD_GET_OR_RETURN(ewkView, smartData, false); EWK_VIEW_PRIV_GET_OR_RETURN(smartData, priv, false); float currentScaleFactor = ewk_view_scale_get(ewkView); if (currentScaleFactor == -1) return false; int x, y; ewk_frame_scroll_pos_get(smartData->main_frame, &x, &y); x = static_cast<int>(((x + centerX) / currentScaleFactor) * scaleFactor) - centerX; y = static_cast<int>(((y + centerY) / currentScaleFactor) * scaleFactor) - centerY; priv->page->setPageScaleFactor(scaleFactor, WebCore::LayoutPoint(x, y)); return true; }
Use "void" for empty parameter of public APIs
Right
EAPI Ewk_Context *ewk_context_new(void);
Wrong
EAPI Ewk_Context *ewk_context_new();
Place '*' operator to data type
Right
static void _ewk_view_smart_show(Evas_Object* ewkView)
Wrong
static void _ewk_view_smart_show(Evas_Object *ewkView)
Use C++ casting for type casting
Right
Ewk_View_Smart_Data* smartData = static_cast<Ewk_View_Smart_Data*>(data);
Wrong
Ewk_View_Smart_Data* smartData = (Ewk_View_Smart_Data*)data;
Use smart pointers
Right
RefPtr<cairo_region_t> dirtyRegion = adoptRef(cairo_region_create_rectangle(&rect)); or OwnPtr<WebCore::Page> page = adoptPtr(new WebCore::Page(pageClients));
Wrong
cairo_region_t* dirtyRegion = cairo_region_create_rectangle(&rect); ... cairo_region_destroy(dirtyRegion); or WebCore::Page* page = new WebCore::Page(pageClients); ... delete page;
Use c++ new/delete operators
Right
Where it is not possible to use smart pointers. Use new/delete operators.
unusedCacheEntry = new Ewk_Tile_Unused_Cache_Entry; ... delete unusedCacheEntry;
Wrong
unusedCacheEntry = static_cast<Ewk_Tile_Unused_Cache_Entry*>(malloc(sizeof(Ewk_Tile_Unused_Cache_Entry))); ... free(unusedCacheEntry);
Use const keyword instead of #define when you define constant variable
Right
const int defaultTileWidth = 256; const int defaultTileHeigth = 256;
Wrong
#define DEFAULT_TILE_W (256) #define DEFAULT_TILE_H (256)
Use NULL in public C headers instead of 0 (but keep using 0 in implementations and in private headers).
Right
/** * Query action for this intent. * * @param intent intent object to query. * * @return the intent action if successful or @c NULL otherwise. */ EAPI const char *ewk_intent_action_get(const Ewk_Intent *intent);
Wrong
/** * Query action for this intent. * * @param intent intent object to query. * * @return the intent action if successful or @c 0 otherwise. */ EAPI const char *ewk_intent_action_get(const Ewk_Intent *intent);
Use a double negation when you modify or compare with a Eina Bool member variable which stores a value in a bit field.
Eina_Bool
is an unsigned char
typedef, which means one can in theory pass a value such as 3 or 42 to it. This can be problematic if one is storing an Eina_Bool
in a bitfield, since only the last bit will be used. For example:
struct MyStruct { Eina_Bool b : 1; }; void foo() { Eina_Bool v1 = 2, v2 = 3; MyStruct s; s.b = v1; // b is 0, since the least significant bit is 0 (2 == 10 in binary) s.b = v2; // b is 1, since the least significant bit is 1 (3 == 11 in binary) }
On the other hand, if an Eina_Bool
is simply being obtained from some publicly-visible API and passed to another function that takes a bool
, or if a bitfield is made from bool
s instead of Eina_Bool
s, this does not happen, since, according to the C++ standard, any value that is not zero, a null pointer or a null member pointer is converted to true
.
Right
struct _Ewk_View_Private_Data { ... Eina_Bool pageCache : 1; } Eina_Bool ewk_view_setting_page_cache_set(Evas_Object* ewkView, Eina_Bool enable) { EWK_VIEW_SD_GET_OR_RETURN(ewkView, smartData, false); EWK_VIEW_PRIV_GET_OR_RETURN(smartData, priv, false); enable = !!enable; if (priv->settings.pageCache != enable) { priv->pageSettings->setUsesPageCache(enable); priv->settings.pageCache = enable; } return true; }
Wrong
Eina_Bool ewk_settings_auto_load_images_set(Ewk_Settings* settings, Eina_Bool automatic) { EINA_SAFETY_ON_NULL_RETURN_VAL(settings, false); automatic = !!automatic; WKPreferencesSetLoadsImagesAutomatically(settings->preferences.get(), automatic); return true; }
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