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Codechange: Split MakeNWidget to improve readability. (OpenTTD#12785)
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Split MakeNWidget() into two stages, widget-creation and attribute-applying, to reduce function size and make it clearer.
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@PeterN
PeterN authored Jun 15, 2024
1 parent 22d70f9 commit b991a39
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Showing 2 changed files with 169 additions and 169 deletions.
331 changes: 164 additions & 167 deletions src/widget.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2957,192 +2957,189 @@ bool NWidgetLeaf::ButtonHit(const Point &pt)
/* == Conversion code from NWidgetPart array to NWidgetBase* tree == */

/**
* Construct a single nested widget in \a *dest from its parts.
*
* Construct a NWidgetBase object from a #NWidget function, and apply all
* settings that follow it, until encountering a #EndContainer, another
* #NWidget, or the end of the parts array.
*
* @param nwid_begin Iterator to beginning of nested widget parts.
* @param nwid_end Iterator to ending of nested widget parts.
* @param dest Address of pointer to use for returning the composed widget.
* @param fill_dest Fill the composed widget with child widgets.
* @return Iterator to remaining nested widget parts.
* Test if (an NWidgetPart) WidgetType is an attribute widget part type.
* @param tp WidgetType to test.
* @return True iff WidgetType is an attribute widget.
*/
static std::span<const NWidgetPart>::iterator MakeNWidget(std::span<const NWidgetPart>::iterator nwid_begin, std::span<const NWidgetPart>::iterator nwid_end, std::unique_ptr<NWidgetBase> &dest, bool *fill_dest)
static bool IsAttributeWidgetPartType(WidgetType tp)
{
dest = nullptr;
*fill_dest = false;

while (nwid_begin < nwid_end) {
switch (nwid_begin->type) {
case NWID_SPACER:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetSpacer>(0, 0);
break;

case NWID_HORIZONTAL:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetHorizontal>(nwid_begin->u.cont_flags);
*fill_dest = true;
break;

case NWID_HORIZONTAL_LTR:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetHorizontalLTR>(nwid_begin->u.cont_flags);
*fill_dest = true;
break;

case WWT_PANEL:
case WWT_INSET:
case WWT_FRAME:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetBackground>(nwid_begin->type, nwid_begin->u.widget.colour, nwid_begin->u.widget.index);
*fill_dest = true;
break;

case NWID_VERTICAL:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetVertical>(nwid_begin->u.cont_flags);
*fill_dest = true;
break;

case NWID_MATRIX: {
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetMatrix>(nwid_begin->u.widget.colour, nwid_begin->u.widget.index);
*fill_dest = true;
break;
}
return tp > WPT_ATTRIBUTE_BEGIN && tp < WPT_ATTRIBUTE_END;
}

case WPT_FUNCTION: {
if (dest != nullptr) return nwid_begin;
dest = nwid_begin->u.func_ptr();
*fill_dest = false;
break;
}
/**
* Apply an attribute NWidgetPart to an NWidget.
* @param nwid Attribute NWidgetPart
* @param dest NWidget to apply attribute to.
* @pre NWidgetPart must be an attribute NWidgetPart.
*/
static void ApplyNWidgetPartAttribute(const NWidgetPart &nwid, NWidgetBase *dest)
{
switch (nwid.type) {
case WPT_RESIZE: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest);
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_RESIZE requires NWidgetResizeBase");
assert(nwid.u.xy.x >= 0 && nwid.u.xy.y >= 0);
nwrb->SetResize(nwid.u.xy.x, nwid.u.xy.y);
break;
}

case WPT_RESIZE: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest.get());
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_RESIZE requires NWidgetResizeBase");
assert(nwid_begin->u.xy.x >= 0 && nwid_begin->u.xy.y >= 0);
nwrb->SetResize(nwid_begin->u.xy.x, nwid_begin->u.xy.y);
break;
}
case WPT_MINSIZE: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest);
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_MINSIZE requires NWidgetResizeBase");
assert(nwid.u.xy.x >= 0 && nwid.u.xy.y >= 0);
nwrb->SetMinimalSize(nwid.u.xy.x, nwid.u.xy.y);
break;
}

case WPT_MINSIZE: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest.get());
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_MINSIZE requires NWidgetResizeBase");
assert(nwid_begin->u.xy.x >= 0 && nwid_begin->u.xy.y >= 0);
nwrb->SetMinimalSize(nwid_begin->u.xy.x, nwid_begin->u.xy.y);
break;
}
case WPT_MINTEXTLINES: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest);
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_MINTEXTLINES requires NWidgetResizeBase");
assert(nwid.u.text_lines.size >= FS_BEGIN && nwid.u.text_lines.size < FS_END);
nwrb->SetMinimalTextLines(nwid.u.text_lines.lines, nwid.u.text_lines.spacing, nwid.u.text_lines.size);
break;
}

case WPT_MINTEXTLINES: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest.get());
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_MINTEXTLINES requires NWidgetResizeBase");
assert(nwid_begin->u.text_lines.size >= FS_BEGIN && nwid_begin->u.text_lines.size < FS_END);
nwrb->SetMinimalTextLines(nwid_begin->u.text_lines.lines, nwid_begin->u.text_lines.spacing, nwid_begin->u.text_lines.size);
break;
}
case WPT_TEXTSTYLE: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest);
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_TEXTSTYLE requires NWidgetCore");
nwc->SetTextStyle(nwid.u.text_style.colour, nwid.u.text_style.size);
break;
}

case WPT_TEXTSTYLE: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest.get());
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_TEXTSTYLE requires NWidgetCore");
nwc->SetTextStyle(nwid_begin->u.text_style.colour, nwid_begin->u.text_style.size);
break;
}
case WPT_ALIGNMENT: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest);
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_ALIGNMENT requires NWidgetCore");
nwc->SetAlignment(nwid.u.align.align);
break;
}

case WPT_ALIGNMENT: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest.get());
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_ALIGNMENT requires NWidgetCore");
nwc->SetAlignment(nwid_begin->u.align.align);
break;
}
case WPT_FILL: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest);
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_FILL requires NWidgetResizeBase");
nwrb->SetFill(nwid.u.xy.x, nwid.u.xy.y);
break;
}

case WPT_FILL: {
NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(dest.get());
if (nwrb == nullptr) [[unlikely]] throw std::runtime_error("WPT_FILL requires NWidgetResizeBase");
nwrb->SetFill(nwid_begin->u.xy.x, nwid_begin->u.xy.y);
break;
}
case WPT_DATATIP: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest);
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_DATATIP requires NWidgetCore");
nwc->widget_data = nwid.u.data_tip.data;
nwc->tool_tip = nwid.u.data_tip.tooltip;
break;
}

case WPT_DATATIP: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest.get());
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_DATATIP requires NWidgetCore");
nwc->widget_data = nwid_begin->u.data_tip.data;
nwc->tool_tip = nwid_begin->u.data_tip.tooltip;
break;
}
case WPT_PADDING:
if (dest == nullptr) [[unlikely]] throw std::runtime_error("WPT_PADDING requires NWidgetBase");
dest->SetPadding(nwid.u.padding);
break;

case WPT_PADDING:
if (dest == nullptr) [[unlikely]] throw std::runtime_error("WPT_PADDING requires NWidgetBase");
dest->SetPadding(nwid_begin->u.padding);
break;
case WPT_PIPSPACE: {
NWidgetPIPContainer *nwc = dynamic_cast<NWidgetPIPContainer *>(dest);
if (nwc != nullptr) nwc->SetPIP(nwid.u.pip.pre, nwid.u.pip.inter, nwid.u.pip.post);

case WPT_PIPSPACE: {
NWidgetPIPContainer *nwc = dynamic_cast<NWidgetPIPContainer *>(dest.get());
if (nwc != nullptr) nwc->SetPIP(nwid_begin->u.pip.pre, nwid_begin->u.pip.inter, nwid_begin->u.pip.post);
NWidgetBackground *nwb = dynamic_cast<NWidgetBackground *>(dest);
if (nwb != nullptr) nwb->SetPIP(nwid.u.pip.pre, nwid.u.pip.inter, nwid.u.pip.post);

NWidgetBackground *nwb = dynamic_cast<NWidgetBackground *>(dest.get());
if (nwb != nullptr) nwb->SetPIP(nwid_begin->u.pip.pre, nwid_begin->u.pip.inter, nwid_begin->u.pip.post);
if (nwc == nullptr && nwb == nullptr) [[unlikely]] throw std::runtime_error("WPT_PIPSPACE requires NWidgetPIPContainer or NWidgetBackground");
break;
}

if (nwc == nullptr && nwb == nullptr) [[unlikely]] throw std::runtime_error("WPT_PIPSPACE requires NWidgetPIPContainer or NWidgetBackground");
break;
}
case WPT_PIPRATIO: {
NWidgetPIPContainer *nwc = dynamic_cast<NWidgetPIPContainer *>(dest);
if (nwc != nullptr) nwc->SetPIPRatio(nwid.u.pip.pre, nwid.u.pip.inter, nwid.u.pip.post);

case WPT_PIPRATIO: {
NWidgetPIPContainer *nwc = dynamic_cast<NWidgetPIPContainer *>(dest.get());
if (nwc != nullptr) nwc->SetPIPRatio(nwid_begin->u.pip.pre, nwid_begin->u.pip.inter, nwid_begin->u.pip.post);
NWidgetBackground *nwb = dynamic_cast<NWidgetBackground *>(dest);
if (nwb != nullptr) nwb->SetPIPRatio(nwid.u.pip.pre, nwid.u.pip.inter, nwid.u.pip.post);

NWidgetBackground *nwb = dynamic_cast<NWidgetBackground *>(dest.get());
if (nwb != nullptr) nwb->SetPIPRatio(nwid_begin->u.pip.pre, nwid_begin->u.pip.inter, nwid_begin->u.pip.post);
if (nwc == nullptr && nwb == nullptr) [[unlikely]] throw std::runtime_error("WPT_PIPRATIO requires NWidgetPIPContainer or NWidgetBackground");
break;
}

if (nwc == nullptr && nwb == nullptr) [[unlikely]] throw std::runtime_error("WPT_PIPRATIO requires NWidgetPIPContainer or NWidgetBackground");
break;
}
case WPT_SCROLLBAR: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest);
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_SCROLLBAR requires NWidgetCore");
nwc->scrollbar_index = nwid.u.widget.index;
break;
}

case WPT_SCROLLBAR: {
NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(dest.get());
if (nwc == nullptr) [[unlikely]] throw std::runtime_error("WPT_SCROLLBAR requires NWidgetCore");
nwc->scrollbar_index = nwid_begin->u.widget.index;
break;
}
case WPT_ASPECT: {
if (dest == nullptr) [[unlikely]] throw std::runtime_error("WPT_ASPECT requires NWidgetBase");
dest->aspect_ratio = nwid.u.aspect.ratio;
dest->aspect_flags = nwid.u.aspect.flags;
break;
}

case WPT_ASPECT: {
if (dest == nullptr) [[unlikely]] throw std::runtime_error("WPT_ASPECT requires NWidgetBase");
dest->aspect_ratio = nwid_begin->u.aspect.ratio;
dest->aspect_flags = nwid_begin->u.aspect.flags;
break;
}
default:
NOT_REACHED();
}
}

case WPT_ENDCONTAINER:
return nwid_begin;

case NWID_VIEWPORT:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetViewport>(nwid_begin->u.widget.index);
break;

case NWID_HSCROLLBAR:
case NWID_VSCROLLBAR:
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetScrollbar>(nwid_begin->type, nwid_begin->u.widget.colour, nwid_begin->u.widget.index);
break;

case NWID_SELECTION: {
if (dest != nullptr) return nwid_begin;
dest = std::make_unique<NWidgetStacked>(nwid_begin->u.widget.index);
*fill_dest = true;
break;
}
/**
* Make NWidget from an NWidgetPart.
* @param nwid NWidgetPart.
* @pre NWidgetPart must not be an attribute NWidgetPart nor WPT_ENDCONTAINER.
* @return Pointer to created NWidget.
*/
static std::unique_ptr<NWidgetBase> MakeNWidget(const NWidgetPart &nwid)
{
assert(!IsAttributeWidgetPartType(nwid.type));
assert(nwid.type != WPT_ENDCONTAINER);

default:
if (dest != nullptr) return nwid_begin;
assert((nwid_begin->type & WWT_MASK) < WWT_LAST || (nwid_begin->type & WWT_MASK) == NWID_BUTTON_DROPDOWN);
dest = std::make_unique<NWidgetLeaf>(nwid_begin->type, nwid_begin->u.widget.colour, nwid_begin->u.widget.index, 0x0, STR_NULL);
break;
}
nwid_begin++;
switch (nwid.type) {
case NWID_SPACER: return std::make_unique<NWidgetSpacer>(0, 0);

case WWT_PANEL: [[fallthrough]];
case WWT_INSET: [[fallthrough]];
case WWT_FRAME: return std::make_unique<NWidgetBackground>(nwid.type, nwid.u.widget.colour, nwid.u.widget.index);

case NWID_HORIZONTAL: return std::make_unique<NWidgetHorizontal>(nwid.u.cont_flags);
case NWID_HORIZONTAL_LTR: return std::make_unique<NWidgetHorizontalLTR>(nwid.u.cont_flags);
case NWID_VERTICAL: return std::make_unique<NWidgetVertical>(nwid.u.cont_flags);
case NWID_SELECTION: return std::make_unique<NWidgetStacked>(nwid.u.widget.index);
case NWID_MATRIX: return std::make_unique<NWidgetMatrix>(nwid.u.widget.colour, nwid.u.widget.index);
case NWID_VIEWPORT: return std::make_unique<NWidgetViewport>(nwid.u.widget.index);

case NWID_HSCROLLBAR: [[fallthrough]];
case NWID_VSCROLLBAR: return std::make_unique<NWidgetScrollbar>(nwid.type, nwid.u.widget.colour, nwid.u.widget.index);

case WPT_FUNCTION: return nwid.u.func_ptr();

default:
assert((nwid.type & WWT_MASK) < WWT_LAST || (nwid.type & WWT_MASK) == NWID_BUTTON_DROPDOWN);
return std::make_unique<NWidgetLeaf>(nwid.type, nwid.u.widget.colour, nwid.u.widget.index, 0x0, STR_NULL);
}
}

/**
* Construct a single nested widget in \a *dest from its parts.
*
* Construct a NWidgetBase object from a #NWidget function, and apply all
* attributes that follow it, until encountering a #EndContainer, another
* #NWidget, or the end of the parts array.
*
* @param nwid_begin Iterator to beginning of nested widget parts.
* @param nwid_end Iterator to ending of nested widget parts.
* @param[out] dest Address of pointer to use for returning the composed widget.
* @param[out] fill_dest Fill the composed widget with child widgets.
* @return Iterator to remaining nested widget parts.
*/
static std::span<const NWidgetPart>::iterator MakeNWidget(std::span<const NWidgetPart>::iterator nwid_begin, std::span<const NWidgetPart>::iterator nwid_end, std::unique_ptr<NWidgetBase> &dest, bool &fill_dest)
{
dest = nullptr;

if (IsAttributeWidgetPartType(nwid_begin->type)) [[unlikely]] throw std::runtime_error("Expected non-attribute NWidgetPart type");
if (nwid_begin->type == WPT_ENDCONTAINER) return nwid_begin;

fill_dest = IsContainerWidgetType(nwid_begin->type);
dest = MakeNWidget(*nwid_begin);
if (dest == nullptr) return nwid_begin;

++nwid_begin;

/* Once a widget is created, we're now looking for attributes. */
while (nwid_begin != nwid_end && IsAttributeWidgetPartType(nwid_begin->type)) {
ApplyNWidgetPartAttribute(*nwid_begin, dest.get());
++nwid_begin;
}

return nwid_begin;
Expand Down Expand Up @@ -3174,10 +3171,10 @@ static std::span<const NWidgetPart>::iterator MakeWidgetTree(std::span<const NWi
NWidgetBackground *nwid_parent = dynamic_cast<NWidgetBackground *>(parent.get());
assert(parent == nullptr || (nwid_cont != nullptr && nwid_parent == nullptr) || (nwid_cont == nullptr && nwid_parent != nullptr));

for (;;) {
while (nwid_begin != nwid_end) {
std::unique_ptr<NWidgetBase> sub_widget = nullptr;
bool fill_sub = false;
nwid_begin = MakeNWidget(nwid_begin, nwid_end, sub_widget, &fill_sub);
nwid_begin = MakeNWidget(nwid_begin, nwid_end, sub_widget, fill_sub);

/* Break out of loop when end reached */
if (sub_widget == nullptr) break;
Expand Down
7 changes: 5 additions & 2 deletions src/widget_type.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,7 @@ enum WidgetType {
NWID_CUSTOM, ///< General Custom widget.

/* Nested widget part types. */
WPT_ATTRIBUTE_BEGIN, ///< Begin marker for attribute NWidgetPart types.
WPT_RESIZE, ///< Widget part for specifying resizing.
WPT_MINSIZE, ///< Widget part for specifying minimal size.
WPT_MINTEXTLINES, ///< Widget part for specifying minimal number of lines of text.
Expand All @@ -97,10 +98,12 @@ enum WidgetType {
WPT_PIPRATIO, ///< Widget part for specifying pre/inter/post ratio for containers.
WPT_TEXTSTYLE, ///< Widget part for specifying text colour.
WPT_ALIGNMENT, ///< Widget part for specifying text/image alignment.
WPT_ENDCONTAINER, ///< Widget part to denote end of a container.
WPT_FUNCTION, ///< Widget part for calling a user function.
WPT_SCROLLBAR, ///< Widget part for attaching a scrollbar.
WPT_ASPECT, ///< Widget part for sepcifying aspect ratio.
WPT_ATTRIBUTE_END, ///< End marker for attribute NWidgetPart types.

WPT_FUNCTION, ///< Widget part for calling a user function.
WPT_ENDCONTAINER, ///< Widget part to denote end of a container.

/* Pushable window widget types. */
WWT_MASK = 0x7F,
Expand Down

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