(svn r16837) -Codechange: Collect largest used index while constructing nested widget tree.

5 files changed, 83 insertions, 39 deletions

diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp
index 94a1a5122..3a8f03967 100644
--- a/src/graph_gui.cpp
+++ b/src/graph_gui.cpp
@@ -86,7 +86,13 @@ struct GraphLegendWindow : Window {
 	}
 };
 
-static NWidgetBase *MakeNWidgetCompanyLines()
+/**
+ * Construct a vertical list of buttons, one for each company.
+ * @param biggest_index Storage for collecting the biggest index used in the returned tree.
+ * @return Panel with company buttons.
+ * @postcond \c *biggest_index contains the largest used index in the tree.
+ */
+static NWidgetBase *MakeNWidgetCompanyLines(int *biggest_index)
 {
 	NWidgetVertical *vert = new NWidgetVertical();
 
@@ -97,6 +103,7 @@ static NWidgetBase *MakeNWidgetCompanyLines()
 		panel->SetDataTip(0x0, STR_GRAPH_KEY_COMPANY_SELECTION);
 		vert->Add(panel);
 	}
+	*biggest_index = GLW_LAST_COMPANY;
 	return vert;
 }
 
@@ -1195,8 +1202,12 @@ struct PerformanceRatingDetailWindow : Window {
 
 CompanyID PerformanceRatingDetailWindow::company = INVALID_COMPANY;
 
-/** Make a vertical list of panels for outputting score details. */
-static NWidgetBase *MakePerformanceDetailPanels()
+/** Make a vertical list of panels for outputting score details.
+ * @param biggest_index Storage for collecting the biggest index used in the returned tree.
+ * @return Panel with performance details.
+ * @postcond \c *biggest_index contains the largest used index in the tree.
+ */
+static NWidgetBase *MakePerformanceDetailPanels(int *biggest_index)
 {
 	const StringID performance_tips[] = {
 		STR_PERFORMANCE_DETAIL_VEHICLES_TIP,
@@ -1221,11 +1232,17 @@ static NWidgetBase *MakePerformanceDetailPanels()
 		panel->SetDataTip(0x0, performance_tips[widnum - PRW_SCORE_FIRST]);
 		vert->Add(panel);
 	}
+	*biggest_index = PRW_SCORE_LAST;
 	return vert;
 }
 
-/** Make a number of rows with button-like graphics, for enabling/disabling each company. */
-static NWidgetBase *MakeCompanyButtonRows()
+/**
+ * Make a number of rows with button-like graphics, for enabling/disabling each company.
+ * @param biggest_index Storage for collecting the biggest index used in the returned tree.
+ * @return Panel with rows of company buttons.
+ * @postcond \c *biggest_index contains the largest used index in the tree.
+ */
+static NWidgetBase *MakeCompanyButtonRows(int *biggest_index)
 {
 	static const int MAX_LENGTH = 8; // Maximal number of company buttons in one row.
 	NWidgetVertical *vert = NULL; // Storage for all rows.
@@ -1252,6 +1269,7 @@ static NWidgetBase *MakeCompanyButtonRows()
 		hor->Add(panel);
 		hor_length++;
 	}
+	*biggest_index = PRW_COMPANY_LAST;
 	if (vert == NULL) return hor; // All buttons fit in a single row.
 
 	if (hor_length > 0 && hor_length < MAX_LENGTH) {
diff --git a/src/news_gui.cpp b/src/news_gui.cpp
index a91155220..0704d838c 100644
--- a/src/news_gui.cpp
+++ b/src/news_gui.cpp
@@ -1081,7 +1081,13 @@ NEWS_SETTINGS_LINE(28, NT_GENERAL),
 {   WIDGETS_END},
 };
 
-static NWidgetBase *MakeNewsSettingLines()
+/**
+ * Make nested widget tree for the news settings.
+ * @param biggest_index Storage for collecting the biggest index used in the returned tree.
+ * @return Panel with rows of news settings.
+ * @postcond \c *biggest_index contains the largest used index in the tree.
+ */
+static NWidgetBase *MakeNewsSettingLines(int *biggest_index)
 {
 	const int NEWS_SETTING_HEIGHT = 12; // Height of one line.
 	NWidgetVertical *vert = new NWidgetVertical;
@@ -1110,6 +1116,7 @@ static NWidgetBase *MakeNewsSettingLines()
 
 		vert->Add(hor);
 	}
+	*biggest_index = widnum - 1;
 	return vert;
 }
 
diff --git a/src/osk_gui.cpp b/src/osk_gui.cpp
index 43b434edb..302278e6d 100644
--- a/src/osk_gui.cpp
+++ b/src/osk_gui.cpp
@@ -3,6 +3,7 @@
 /** @file osk_gui.cpp The On Screen Keyboard GUI */
 
 #include "stdafx.h"
+#include "core/math_func.hpp"
 #include "string_func.h"
 #include "strings_func.h"
 #include "debug.h"
@@ -336,9 +337,10 @@ static const int INTER_KEY_SPACE = 2; // Number of pixels between two keys.
  * @param widtype Widget type of the key. Must be either \c NWID_SPACER for an invisible key, or a \c WWT_* widget.
  * @param widnum  Widget number of the key.
  * @param widdata Data value of the key widget.
+ * @param biggest_index Collected biggest widget index so far.
  * @note Key width is measured in 1/2 keys to allow for 1/2 key shifting between rows.
  */
-static void AddKey(NWidgetHorizontal *hor, int height, int num_half, WidgetType widtype, int widnum, uint16 widdata)
+static void AddKey(NWidgetHorizontal *hor, int height, int num_half, WidgetType widtype, int widnum, uint16 widdata, int *biggest_index)
 {
 	int key_width = HALF_KEY_WIDTH + (INTER_KEY_SPACE + HALF_KEY_WIDTH) * (num_half - 1);
 
@@ -355,84 +357,86 @@ static void AddKey(NWidgetHorizontal *hor, int height, int num_half, WidgetType
 		leaf->SetMinimalSize(key_width, height);
 		hor->Add(leaf);
 	}
+
+	*biggest_index = max(*biggest_index, widnum);
 }
 
 /** Construct the top row keys (cancel, ok, backspace). */
-static NWidgetBase *MakeTopKeys()
+static NWidgetBase *MakeTopKeys(int *biggest_index)
 {
 	NWidgetHorizontal *hor = new NWidgetHorizontal;
 	int key_height = 12;
 
-	AddKey(hor, key_height, 6 * 2, WWT_TEXTBTN,    OSK_WIDGET_CANCEL,    STR_QUERY_CANCEL);
-	AddKey(hor, key_height, 6 * 2, WWT_TEXTBTN,    OSK_WIDGET_OK,        STR_QUERY_OK);
-	AddKey(hor, key_height, 2 * 2, WWT_PUSHIMGBTN, OSK_WIDGET_BACKSPACE, SPR_OSK_BACKSPACE);
+	AddKey(hor, key_height, 6 * 2, WWT_TEXTBTN,    OSK_WIDGET_CANCEL,    STR_QUERY_CANCEL,  biggest_index);
+	AddKey(hor, key_height, 6 * 2, WWT_TEXTBTN,    OSK_WIDGET_OK,        STR_QUERY_OK,      biggest_index);
+	AddKey(hor, key_height, 2 * 2, WWT_PUSHIMGBTN, OSK_WIDGET_BACKSPACE, SPR_OSK_BACKSPACE, biggest_index);
 	return hor;
 }
 
 /** Construct the row containing the digit keys. */
-static NWidgetBase *MakeNumberKeys()
+static NWidgetBase *MakeNumberKeys(int *biggest_index)
 {
 	NWidgetHorizontal *hor = new NWidgetHorizontal;
 	int key_height = 16;
 
 	for (int widnum = OSK_WIDGET_NUMBERS_FIRST; widnum <= OSK_WIDGET_NUMBERS_LAST; widnum++) {
-		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0);
+		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0, biggest_index);
 	}
 	return hor;
 }
 
 /** Construct the qwerty row keys. */
-static NWidgetBase *MakeQwertyKeys()
+static NWidgetBase *MakeQwertyKeys(int *biggest_index)
 {
 	NWidgetHorizontal *hor = new NWidgetHorizontal;
 	int key_height = 16;
 
-	AddKey(hor, key_height, 3, WWT_PUSHIMGBTN, OSK_WIDGET_SPECIAL, SPR_OSK_SPECIAL);
+	AddKey(hor, key_height, 3, WWT_PUSHIMGBTN, OSK_WIDGET_SPECIAL, SPR_OSK_SPECIAL, biggest_index);
 	for (int widnum = OSK_WIDGET_QWERTY_FIRST; widnum <= OSK_WIDGET_QWERTY_LAST; widnum++) {
-		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0);
+		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0, biggest_index);
 	}
-	AddKey(hor, key_height, 1, NWID_SPACER, 0, 0);
+	AddKey(hor, key_height, 1, NWID_SPACER, 0, 0, biggest_index);
 	return hor;
 }
 
 /** Construct the asdfg row keys. */
-static NWidgetBase *MakeAsdfgKeys()
+static NWidgetBase *MakeAsdfgKeys(int *biggest_index)
 {
 	NWidgetHorizontal *hor = new NWidgetHorizontal;
 	int key_height = 16;
 
-	AddKey(hor, key_height, 4, WWT_IMGBTN, OSK_WIDGET_CAPS, SPR_OSK_CAPS);
+	AddKey(hor, key_height, 4, WWT_IMGBTN, OSK_WIDGET_CAPS, SPR_OSK_CAPS, biggest_index);
 	for (int widnum = OSK_WIDGET_ASDFG_FIRST; widnum <= OSK_WIDGET_ASDFG_LAST; widnum++) {
-		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0);
+		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0, biggest_index);
 	}
 	return hor;
 }
 
 /** Construct the zxcvb row keys. */
-static NWidgetBase *MakeZxcvbKeys()
+static NWidgetBase *MakeZxcvbKeys(int *biggest_index)
 {
 	NWidgetHorizontal *hor = new NWidgetHorizontal;
 	int key_height = 16;
 
-	AddKey(hor, key_height, 3, WWT_IMGBTN, OSK_WIDGET_SHIFT, SPR_OSK_SHIFT);
+	AddKey(hor, key_height, 3, WWT_IMGBTN, OSK_WIDGET_SHIFT, SPR_OSK_SHIFT, biggest_index);
 	for (int widnum = OSK_WIDGET_ZXCVB_FIRST; widnum <= OSK_WIDGET_ZXCVB_LAST; widnum++) {
-		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0);
+		AddKey(hor, key_height, 2, WWT_PUSHBTN, widnum, 0x0, biggest_index);
 	}
-	AddKey(hor, key_height, 1, NWID_SPACER, 0, 0);
+	AddKey(hor, key_height, 1, NWID_SPACER, 0, 0, biggest_index);
 	return hor;
 }
 
 /** Construct the spacebar row keys. */
-static NWidgetBase *MakeSpacebarKeys()
+static NWidgetBase *MakeSpacebarKeys(int *biggest_index)
 {
 	NWidgetHorizontal *hor = new NWidgetHorizontal;
 	int key_height = 16;
 
-	AddKey(hor, key_height,  8, NWID_SPACER, 0, 0);
-	AddKey(hor, key_height, 13, WWT_PUSHTXTBTN, OSK_WIDGET_SPACE, STR_EMPTY);
-	AddKey(hor, key_height,  3, NWID_SPACER, 0, 0);
-	AddKey(hor, key_height,  2, WWT_PUSHIMGBTN, OSK_WIDGET_LEFT,  SPR_OSK_LEFT);
-	AddKey(hor, key_height,  2, WWT_PUSHIMGBTN, OSK_WIDGET_RIGHT, SPR_OSK_RIGHT);
+	AddKey(hor, key_height,  8, NWID_SPACER, 0, 0, biggest_index);
+	AddKey(hor, key_height, 13, WWT_PUSHTXTBTN, OSK_WIDGET_SPACE, STR_EMPTY, biggest_index);
+	AddKey(hor, key_height,  3, NWID_SPACER, 0, 0, biggest_index);
+	AddKey(hor, key_height,  2, WWT_PUSHIMGBTN, OSK_WIDGET_LEFT,  SPR_OSK_LEFT, biggest_index);
+	AddKey(hor, key_height,  2, WWT_PUSHIMGBTN, OSK_WIDGET_RIGHT, SPR_OSK_RIGHT, biggest_index);
 	return hor;
 }
 
diff --git a/src/widget.cpp b/src/widget.cpp
index 027319e43..c96f1d7b8 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -2255,9 +2255,11 @@ bool CompareWidgetArrays(const Widget *orig, const Widget *gen, bool report)
  * @param count Length of the \a parts array.
  * @param dest  Address of pointer to use for returning the composed widget.
  * @param fill_dest Fill the composed widget with child widgets.
+ * @param biggest_index Pointer to biggest nested widget index in the tree encountered so far.
  * @return Number of widget part elements used to compose the widget.
+ * @precond \c biggest_index != NULL.
  */
-static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest, bool *fill_dest)
+static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest, bool *fill_dest, int *biggest_index)
 {
 	int num_used = 0;
 
@@ -2288,6 +2290,7 @@ static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest,
 			case WWT_FRAME:
 				if (*dest != NULL) return num_used;
 				*dest = new NWidgetBackground(parts->type, parts->u.widget.colour, parts->u.widget.index);
+				*biggest_index = max(*biggest_index, (int)parts->u.widget.index);
 				*fill_dest = true;
 				break;
 
@@ -2297,11 +2300,15 @@ static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest,
 				*fill_dest = true;
 				break;
 
-			case WPT_FUNCTION:
+			case WPT_FUNCTION: {
 				if (*dest != NULL) return num_used;
-				*dest = parts->u.func_ptr();
+				/* Ensure proper functioning even when the called code simply writes its largest index. */
+				int biggest = -1;
+				*dest = parts->u.func_ptr(&biggest);
+				*biggest_index = max(*biggest_index, biggest);
 				*fill_dest = false;
 				break;
+			}
 
 			case NWID_SELECTION:
 			case NWID_LAYERED:
@@ -2391,6 +2398,7 @@ static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest,
 				if (*dest != NULL) return num_used;
 				assert((parts->type & WWT_MASK) < NWID_HORIZONTAL);
 				*dest = new NWidgetLeaf(parts->type, parts->u.widget.colour, parts->u.widget.index, 0x0, STR_NULL);
+				*biggest_index = max(*biggest_index, (int)parts->u.widget.index);
 				break;
 		}
 		num_used++;
@@ -2405,9 +2413,11 @@ static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest,
  * @param parts  Array with parts of the nested widgets.
  * @param count  Length of the \a parts array.
  * @param parent Container to use for storing the child widgets.
+ * @param biggest_index Pointer to biggest nested widget index in the tree.
  * @return Number of widget part elements used to fill the container.
+ * @postcond \c *biggest_index contains the largest widget index of the tree and \c -1 if no index is used.
  */
-static int MakeWidgetTree(const NWidgetPart *parts, int count, NWidgetBase *parent)
+static int MakeWidgetTree(const NWidgetPart *parts, int count, NWidgetBase *parent, int *biggest_index)
 {
 	/* Given parent must be either a #NWidgetContainer or a #NWidgetBackground object. */
 	NWidgetContainer *nwid_cont = dynamic_cast<NWidgetContainer *>(parent);
@@ -2418,7 +2428,7 @@ static int MakeWidgetTree(const NWidgetPart *parts, int count, NWidgetBase *pare
 	while (true) {
 		NWidgetBase *sub_widget = NULL;
 		bool fill_sub = false;
-		int num_used = MakeNWidget(parts, count - total_used, &sub_widget, &fill_sub);
+		int num_used = MakeNWidget(parts, count - total_used, &sub_widget, &fill_sub, biggest_index);
 		parts += num_used;
 		total_used += num_used;
 
@@ -2433,7 +2443,7 @@ static int MakeWidgetTree(const NWidgetPart *parts, int count, NWidgetBase *pare
 		WidgetType tp = sub_widget->type;
 		if (fill_sub && (tp == NWID_HORIZONTAL || tp == NWID_HORIZONTAL_LTR || tp == NWID_VERTICAL
 							|| tp == WWT_PANEL || tp == WWT_FRAME || tp == WWT_INSET || tp == NWID_SELECTION || tp == NWID_LAYERED)) {
-			int num_used = MakeWidgetTree(parts, count - total_used, sub_widget);
+			int num_used = MakeWidgetTree(parts, count - total_used, sub_widget, biggest_index);
 			parts += num_used;
 			total_used += num_used;
 		}
@@ -2455,8 +2465,9 @@ static int MakeWidgetTree(const NWidgetPart *parts, int count, NWidgetBase *pare
  */
 NWidgetContainer *MakeNWidgets(const NWidgetPart *parts, int count)
 {
+	int biggest_index = -1;
 	NWidgetContainer *cont = new NWidgetVertical();
-	MakeWidgetTree(parts, count, cont);
+	MakeWidgetTree(parts, count, cont, &biggest_index);
 	return cont;
 }
 
diff --git a/src/widget_type.h b/src/widget_type.h
index 3106dc8ae..6f2f6ba3d 100644
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -561,8 +561,12 @@ struct NWidgetPartPIP {
 	uint8 pre, inter, post; ///< Amount of space before/between/after child widgets.
 };
 
-/** Pointer to function returning a nested widget. */
-typedef NWidgetBase *NWidgetFunctionType();
+/** Pointer to function returning a nested widget.
+ * @param biggest_index Pointer to storage for collecting the biggest index used in the nested widget.
+ * @return Nested widget (tree).
+ * @postcond \c *biggest_index must contain the value of the biggest index in the returned tree.
+ */
+typedef NWidgetBase *NWidgetFunctionType(int *biggest_index);
 
 /** Partial widget specification to allow NWidgets to be written nested.
  * @ingroup NestedWidgetParts */