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netsurf/render/box_normalise.c

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/*
* Copyright 2005 James Bursa <bursa@users.sourceforge.net>
* Copyright 2003 Phil Mellor <monkeyson@users.sourceforge.net>
* Copyright 2005 John M Bell <jmb202@ecs.soton.ac.uk>
* Copyright 2004 Kevin Bagust <kevin.bagust@ntlworld.com>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/** \file
* Box tree normalisation (implementation).
*/
#include <assert.h>
#include <stdbool.h>
#include "css/css.h"
#include "css/select.h"
#include "render/box.h"
#include "render/table.h"
#include "desktop/gui.h"
#include "utils/log.h"
#include "utils/talloc.h"
/* Define to enable box normalise debug */
#undef BOX_NORMALISE_DEBUG
/**
* Row spanning information for a cell
*/
struct span_info {
/** Number of rows this cell spans */
unsigned int row_span;
/** The cell in this column spans all rows until the end of the table */
bool auto_row;
};
/**
* Column record for a table
*/
struct columns {
/** Current column index */
unsigned int current_column;
/** Number of columns in main part of table 1..max columns */
unsigned int num_columns;
/** Information about columns in main table, array [0, num_columns) */
struct span_info *spans;
/** Number of rows in table */
unsigned int num_rows;
};
static bool box_normalise_table(struct box *table, struct content *c);
static bool box_normalise_table_spans(struct box *table,
struct span_info *spans, struct content *c);
static bool box_normalise_table_row_group(struct box *row_group,
struct columns *col_info,
struct content *c);
static bool box_normalise_table_row(struct box *row,
struct columns *col_info,
struct content *c);
static bool calculate_table_row(struct columns *col_info,
unsigned int col_span, unsigned int row_span,
unsigned int *start_column);
static bool box_normalise_inline_container(struct box *cont, struct content *c);
/**
* Ensure the box tree is correctly nested by adding and removing nodes.
*
* \param block box of type BLOCK, INLINE_BLOCK, or TABLE_CELL
* \param box_pool pool to allocate new boxes in
* \return true on success, false on memory exhaustion
*
* The tree is modified to satisfy the following:
* \code
* parent permitted child nodes
* BLOCK, INLINE_BLOCK BLOCK, INLINE_CONTAINER, TABLE
* INLINE_CONTAINER INLINE, INLINE_BLOCK, FLOAT_LEFT, FLOAT_RIGHT, BR, TEXT
* INLINE, TEXT none
* TABLE at least 1 TABLE_ROW_GROUP
* TABLE_ROW_GROUP at least 1 TABLE_ROW
* TABLE_ROW at least 1 TABLE_CELL
* TABLE_CELL BLOCK, INLINE_CONTAINER, TABLE (same as BLOCK)
* FLOAT_(LEFT|RIGHT) exactly 1 BLOCK or TABLE
* \endcode
*/
bool box_normalise_block(struct box *block, struct content *c)
{
struct box *child;
struct box *next_child;
struct box *table;
css_computed_style *style;
assert(block != NULL);
#ifdef BOX_NORMALISE_DEBUG
LOG(("block %p, block->type %u", block, block->type));
#endif
assert(block->type == BOX_BLOCK || block->type == BOX_INLINE_BLOCK ||
block->type == BOX_TABLE_CELL);
gui_multitask();
for (child = block->children; child != NULL; child = next_child) {
#ifdef BOX_NORMALISE_DEBUG
LOG(("child %p, child->type = %d", child, child->type));
#endif
next_child = child->next; /* child may be destroyed */
switch (child->type) {
case BOX_BLOCK:
/* ok */
if (box_normalise_block(child, c) == false)
return false;
break;
case BOX_INLINE_CONTAINER:
if (box_normalise_inline_container(child, c) == false)
return false;
break;
case BOX_TABLE:
if (box_normalise_table(child, c) == false)
return false;
break;
case BOX_INLINE:
case BOX_INLINE_END:
case BOX_INLINE_BLOCK:
case BOX_FLOAT_LEFT:
case BOX_FLOAT_RIGHT:
case BOX_BR:
case BOX_TEXT:
/* should have been wrapped in inline
container by convert_xml_to_box() */
assert(0);
break;
case BOX_TABLE_ROW_GROUP:
case BOX_TABLE_ROW:
case BOX_TABLE_CELL:
/* insert implied table */
assert(block->style != NULL);
style = nscss_get_blank_style(c, block->style,
box_style_alloc, NULL);
if (style == NULL)
return false;
table = box_create(NULL, style, true, block->href,
block->target, NULL, NULL, c);
if (table == NULL) {
css_computed_style_destroy(style);
return false;
}
table->type = BOX_TABLE;
if (child->prev == NULL)
block->children = table;
else
child->prev->next = table;
table->prev = child->prev;
while (child != NULL && (
child->type == BOX_TABLE_ROW_GROUP ||
child->type == BOX_TABLE_ROW ||
child->type == BOX_TABLE_CELL)) {
box_add_child(table, child);
next_child = child->next;
child->next = NULL;
child = next_child;
}
table->last->next = NULL;
table->next = next_child = child;
if (table->next != NULL)
table->next->prev = table;
else
block->last = table;
table->parent = block;
if (box_normalise_table(table, c) == false)
return false;
break;
default:
assert(0);
}
}
return true;
}
bool box_normalise_table(struct box *table, struct content * c)
{
struct box *child;
struct box *next_child;
struct box *row_group;
css_computed_style *style;
struct columns col_info;
assert(table != NULL);
assert(table->type == BOX_TABLE);
#ifdef BOX_NORMALISE_DEBUG
LOG(("table %p", table));
#endif
col_info.num_columns = 1;
col_info.current_column = 0;
col_info.spans = malloc(2 * sizeof *col_info.spans);
if (col_info.spans == NULL)
return false;
col_info.spans[0].row_span = col_info.spans[1].row_span = 0;
col_info.spans[0].auto_row = false;
col_info.spans[1].auto_row = false;
col_info.num_rows = 0;
for (child = table->children; child != NULL; child = next_child) {
next_child = child->next;
switch (child->type) {
case BOX_TABLE_ROW_GROUP:
/* ok */
if (box_normalise_table_row_group(child,
&col_info, c) == false) {
free(col_info.spans);
return false;
}
break;
case BOX_BLOCK:
case BOX_INLINE_CONTAINER:
case BOX_TABLE:
case BOX_TABLE_ROW:
case BOX_TABLE_CELL:
/* insert implied table row group */
assert(table->style != NULL);
style = nscss_get_blank_style(c, table->style,
box_style_alloc, NULL);
if (style == NULL) {
free(col_info.spans);
return false;
}
row_group = box_create(NULL, style, true, table->href,
table->target, NULL, NULL, c);
if (row_group == NULL) {
css_computed_style_destroy(style);
free(col_info.spans);
return false;
}
row_group->type = BOX_TABLE_ROW_GROUP;
if (child->prev == NULL)
table->children = row_group;
else
child->prev->next = row_group;
row_group->prev = child->prev;
while (child != NULL && (
child->type == BOX_BLOCK ||
child->type == BOX_INLINE_CONTAINER ||
child->type == BOX_TABLE ||
child->type == BOX_TABLE_ROW ||
child->type == BOX_TABLE_CELL)) {
box_add_child(row_group, child);
next_child = child->next;
child->next = NULL;
child = next_child;
}
assert(row_group->last != NULL);
row_group->last->next = NULL;
row_group->next = next_child = child;
if (row_group->next != NULL)
row_group->next->prev = row_group;
else
table->last = row_group;
row_group->parent = table;
if (box_normalise_table_row_group(row_group,
&col_info, c) == false) {
free(col_info.spans);
return false;
}
break;
case BOX_INLINE:
case BOX_INLINE_END:
case BOX_INLINE_BLOCK:
case BOX_FLOAT_LEFT:
case BOX_FLOAT_RIGHT:
case BOX_BR:
case BOX_TEXT:
/* should have been wrapped in inline
container by convert_xml_to_box() */
assert(0);
break;
default:
fprintf(stderr, "%i\n", child->type);
assert(0);
}
}
table->columns = col_info.num_columns;
table->rows = col_info.num_rows;
if (table->children == NULL) {
struct box *row;
#ifdef BOX_NORMALISE_DEBUG
LOG(("table->children == 0, creating implied row"));
#endif
assert(table->style != NULL);
style = nscss_get_blank_style(c, table->style,
box_style_alloc, NULL);
if (style == NULL) {
free(col_info.spans);
return false;
}
row_group = box_create(NULL, style, true, table->href,
table->target, NULL, NULL, c);
if (row_group == NULL) {
css_computed_style_destroy(style);
free(col_info.spans);
return false;
}
row_group->type = BOX_TABLE_ROW_GROUP;
style = nscss_get_blank_style(c, row_group->style,
box_style_alloc, NULL);
if (style == NULL) {
box_free(row_group);
free(col_info.spans);
return false;
}
row = box_create(NULL, style, true, row_group->href,
row_group->target, NULL, NULL, c);
if (row == NULL) {
css_computed_style_destroy(style);
box_free(row_group);
free(col_info.spans);
return false;
}
row->type = BOX_TABLE_ROW;
row->parent = row_group;
row_group->children = row_group->last = row;
row_group->parent = table;
table->children = table->last = row_group;
table->rows = 1;
}
if (box_normalise_table_spans(table, col_info.spans, c) == false) {
free(col_info.spans);
return false;
}
free(col_info.spans);
if (table_calculate_column_types(table) == false)
return false;
#ifdef BOX_NORMALISE_DEBUG
LOG(("table %p done", table));
#endif
return true;
}
/**
* Normalise table cell column/row counts for colspan/rowspan = 0.
* Additionally, generate empty cells.
*
* \param table Table to process
* \param spans Array of length table->columns for use in empty cell detection
* \param c Content containing table
* \return True on success, false on memory exhaustion.
*/
bool box_normalise_table_spans(struct box *table, struct span_info *spans,
struct content *c)
{
struct box *table_row_group;
struct box *table_row;
struct box *table_cell;
unsigned int rows_left = table->rows;
unsigned int col;
/* Clear span data */
memset(spans, 0, table->columns * sizeof(struct span_info));
/* Scan table, filling in width and height of table cells with
* colspan = 0 and rowspan = 0. Also generate empty cells */
for (table_row_group = table->children; table_row_group != NULL;
table_row_group = table_row_group->next) {
for (table_row = table_row_group->children; table_row != NULL;
table_row = table_row->next){
for (table_cell = table_row->children;
table_cell != NULL;
table_cell = table_cell->next) {
/* colspan = 0 -> colspan = 1 */
if (table_cell->columns == 0)
table_cell->columns = 1;
/* rowspan = 0 -> rowspan = rows_left */
if (table_cell->rows == 0)
table_cell->rows = rows_left;
/* Record span information */
for (col = table_cell->start_column;
col < table_cell->start_column +
table_cell->columns; col++) {
spans[col].row_span = table_cell->rows;
}
}
/* Reduce span count of each column */
for (col = 0; col < table->columns; col++) {
if (spans[col].row_span == 0) {
unsigned int start = col;
css_computed_style *style;
struct box *cell, *prev;
/* If it's already zero, then we need
* to generate an empty cell for the
* gap in the row that spans as many
* columns as remain blank.
*/
assert(table_row->style != NULL);
/* Find width of gap */
while (col < table->columns &&
spans[col].row_span ==
0) {
col++;
}
style = nscss_get_blank_style(c,
table_row->style,
box_style_alloc, NULL);
if (style == NULL)
return false;
cell = box_create(NULL, style, true,
table_row->href,
table_row->target,
NULL, NULL, c);
if (cell == NULL) {
css_computed_style_destroy(
style);
return false;
}
cell->type = BOX_TABLE_CELL;
cell->rows = 1;
cell->columns = col - start;
cell->start_column = start;
/* Find place to insert cell */
for (prev = table_row->children;
prev != NULL;
prev = prev->next) {
if (prev->start_column +
prev->columns ==
start)
break;
if (prev->next == NULL)
break;
}
/* Insert it */
if (prev == NULL) {
if (table_row->children != NULL)
table_row->children->
prev = cell;
else
table_row->last = cell;
cell->next =
table_row->children;
table_row->children = cell;
} else {
if (prev->next != NULL)
prev->next->prev = cell;
else
table_row->last = cell;
cell->next = prev->next;
prev->next = cell;
cell->prev = prev;
}
cell->parent = table_row;
} else {
spans[col].row_span--;
}
}
assert(rows_left > 0);
rows_left--;
}
}
return true;
}
bool box_normalise_table_row_group(struct box *row_group,
struct columns *col_info,
struct content * c)
{
struct box *child;
struct box *next_child;
struct box *row;
css_computed_style *style;
assert(row_group != 0);
assert(row_group->type == BOX_TABLE_ROW_GROUP);
#ifdef BOX_NORMALISE_DEBUG
LOG(("row_group %p", row_group));
#endif
for (child = row_group->children; child != NULL; child = next_child) {
next_child = child->next;
switch (child->type) {
case BOX_TABLE_ROW:
/* ok */
if (box_normalise_table_row(child, col_info,
c) == false)
return false;
break;
case BOX_BLOCK:
case BOX_INLINE_CONTAINER:
case BOX_TABLE:
case BOX_TABLE_ROW_GROUP:
case BOX_TABLE_CELL:
/* insert implied table row */
assert(row_group->style != NULL);
style = nscss_get_blank_style(c, row_group->style,
box_style_alloc, NULL);
if (style == NULL)
return false;
row = box_create(NULL, style, true, row_group->href,
row_group->target, NULL, NULL, c);
if (row == NULL) {
css_computed_style_destroy(style);
return false;
}
row->type = BOX_TABLE_ROW;
if (child->prev == NULL)
row_group->children = row;
else
child->prev->next = row;
row->prev = child->prev;
while (child != NULL && (
child->type == BOX_BLOCK ||
child->type == BOX_INLINE_CONTAINER ||
child->type == BOX_TABLE ||
child->type == BOX_TABLE_ROW_GROUP ||
child->type == BOX_TABLE_CELL)) {
box_add_child(row, child);
next_child = child->next;
child->next = NULL;
child = next_child;
}
assert(row->last != NULL);
row->last->next = NULL;
row->next = next_child = child;
if (row->next != NULL)
row->next->prev = row;
else
row_group->last = row;
row->parent = row_group;
if (box_normalise_table_row(row, col_info,
c) == false)
return false;
break;
case BOX_INLINE:
case BOX_INLINE_END:
case BOX_INLINE_BLOCK:
case BOX_FLOAT_LEFT:
case BOX_FLOAT_RIGHT:
case BOX_BR:
case BOX_TEXT:
/* should have been wrapped in inline
container by convert_xml_to_box() */
assert(0);
break;
default:
assert(0);
}
}
if (row_group->children == NULL) {
#ifdef BOX_NORMALISE_DEBUG
LOG(("row_group->children == 0, inserting implied row"));
#endif
assert(row_group->style != NULL);
style = nscss_get_blank_style(c, row_group->style,
box_style_alloc, NULL);
if (style == NULL) {
return false;
}
row = box_create(NULL, style, true, row_group->href,
row_group->target, NULL, NULL, c);
if (row == NULL) {
css_computed_style_destroy(style);
return false;
}
row->type = BOX_TABLE_ROW;
row->parent = row_group;
row_group->children = row_group->last = row;
/* Keep table's row count in sync */
col_info->num_rows++;
}
#ifdef BOX_NORMALISE_DEBUG
LOG(("row_group %p done", row_group));
#endif
return true;
}
bool box_normalise_table_row(struct box *row,
struct columns *col_info,
struct content * c)
{
struct box *child;
struct box *next_child;
struct box *cell = NULL;
css_computed_style *style;
unsigned int i;
assert(row != NULL);
assert(row->type == BOX_TABLE_ROW);
#ifdef BOX_NORMALISE_DEBUG
LOG(("row %p", row));
#endif
for (child = row->children; child != NULL; child = next_child) {
next_child = child->next;
switch (child->type) {
case BOX_TABLE_CELL:
/* ok */
if (box_normalise_block(child, c) == false)
return false;
cell = child;
break;
case BOX_BLOCK:
case BOX_INLINE_CONTAINER:
case BOX_TABLE:
case BOX_TABLE_ROW_GROUP:
case BOX_TABLE_ROW:
/* insert implied table cell */
assert(row->style != NULL);
style = nscss_get_blank_style(c, row->style,
box_style_alloc, NULL);
if (style == NULL)
return false;
cell = box_create(NULL, style, true, row->href,
row->target, NULL, NULL, c);
if (cell == NULL) {
css_computed_style_destroy(style);
return false;
}
cell->type = BOX_TABLE_CELL;
if (child->prev == NULL)
row->children = cell;
else
child->prev->next = cell;
cell->prev = child->prev;
while (child != NULL && (
child->type == BOX_BLOCK ||
child->type == BOX_INLINE_CONTAINER ||
child->type == BOX_TABLE ||
child->type == BOX_TABLE_ROW_GROUP ||
child->type == BOX_TABLE_ROW)) {
box_add_child(cell, child);
next_child = child->next;
child->next = NULL;
child = next_child;
}
assert(cell->last != NULL);
cell->last->next = NULL;
cell->next = next_child = child;
if (cell->next != NULL)
cell->next->prev = cell;
else
row->last = cell;
cell->parent = row;
if (box_normalise_block(cell, c) == false)
return false;
break;
case BOX_INLINE:
case BOX_INLINE_END:
case BOX_INLINE_BLOCK:
case BOX_FLOAT_LEFT:
case BOX_FLOAT_RIGHT:
case BOX_BR:
case BOX_TEXT:
/* should have been wrapped in inline
container by convert_xml_to_box() */
assert(0);
break;
default:
assert(0);
}
if (calculate_table_row(col_info, cell->columns, cell->rows,
&cell->start_column) == false)
return false;
}
/* Update row spanning details for all columns */
for (i = 0; i < col_info->num_columns; i++) {
if (col_info->spans[i].row_span != 0 &&
col_info->spans[i].auto_row == false) {
/* This cell spans rows, and is not an auto row.
* Reduce number of rows left to span */
col_info->spans[i].row_span--;
}
}
/* Reset current column for next row */
col_info->current_column = 0;
/* Increment row counter */
col_info->num_rows++;
#ifdef BOX_NORMALISE_DEBUG
LOG(("row %p done", row));
#endif
return true;
}
/**
* Compute the column index at which the current cell begins.
* Additionally, update the column record to reflect row spanning.
*
* \param col_info Column record
* \param col_span Number of columns that current cell spans
* \param row_span Number of rows that current cell spans
* \param start_column Pointer to location to receive column index
* \return true on success, false on memory exhaustion
*/
bool calculate_table_row(struct columns *col_info,
unsigned int col_span, unsigned int row_span,
unsigned int *start_column)
{
unsigned int cell_start_col = col_info->current_column;
unsigned int cell_end_col;
unsigned int i;
struct span_info *spans;
/* Skip columns with cells spanning from above */
while (col_info->spans[cell_start_col].row_span != 0)
cell_start_col++;
/* Update current column with calculated start */
col_info->current_column = cell_start_col;
/* If this cell has a colspan of 0, then assume 1.
* No other browser supports colspan=0, anyway. */
if (col_span == 0)
col_span = 1;
cell_end_col = cell_start_col + col_span;
if (col_info->num_columns < cell_end_col) {
/* It appears that this row has more columns than
* the maximum recorded for the table so far.
* Allocate more span records. */
spans = realloc(col_info->spans,
sizeof *spans * (cell_end_col + 1));
if (spans == NULL)
return false;
col_info->spans = spans;
col_info->num_columns = cell_end_col;
/* Mark new final column as sentinel */
col_info->spans[cell_end_col].row_span = 0;
col_info->spans[cell_end_col].auto_row = false;
}
/* This cell may span multiple columns. If it also wants to span
* multiple rows, temporarily assume it spans 1 row only. This will
* be fixed up in box_normalise_table_spans() */
for (i = cell_start_col; i < cell_end_col; i++) {
col_info->spans[i].row_span = (row_span == 0) ? 1 : row_span;
col_info->spans[i].auto_row = (row_span == 0);
}
/* Update current column with calculated end. */
col_info->current_column = cell_end_col;
*start_column = cell_start_col;
return true;
}
bool box_normalise_inline_container(struct box *cont, struct content * c)
{
struct box *child;
struct box *next_child;
assert(cont != NULL);
assert(cont->type == BOX_INLINE_CONTAINER);
#ifdef BOX_NORMALISE_DEBUG
LOG(("cont %p", cont));
#endif
for (child = cont->children; child != NULL; child = next_child) {
next_child = child->next;
switch (child->type) {
case BOX_INLINE:
case BOX_INLINE_END:
case BOX_BR:
case BOX_TEXT:
/* ok */
break;
case BOX_INLINE_BLOCK:
/* ok */
if (box_normalise_block(child, c) == false)
return false;
break;
case BOX_FLOAT_LEFT:
case BOX_FLOAT_RIGHT:
/* ok */
assert(child->children != NULL);
switch (child->children->type) {
case BOX_BLOCK:
if (box_normalise_block(child->children,
c) == false)
return false;
break;
case BOX_TABLE:
if (box_normalise_table(child->children,
c) == false)
return false;
break;
default:
assert(0);
}
if (child->children == NULL) {
/* the child has destroyed itself: remove float */
if (child->prev == NULL)
child->parent->children = child->next;
else
child->prev->next = child->next;
if (child->next != NULL)
child->next->prev = child->prev;
else
child->parent->last = child->prev;
box_free(child);
}
break;
case BOX_BLOCK:
case BOX_INLINE_CONTAINER:
case BOX_TABLE:
case BOX_TABLE_ROW_GROUP:
case BOX_TABLE_ROW:
case BOX_TABLE_CELL:
default:
assert(0);
}
}
#ifdef BOX_NORMALISE_DEBUG
LOG(("cont %p done", cont));
#endif
return true;
}
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