/* * This file is part of LibCSS * Licensed under the MIT License, * http://www.opensource.org/licenses/mit-license.php * Copyright 2009 John-Mark Bell */ #include #include #include #include #include "bytecode/bytecode.h" #include "bytecode/opcodes.h" #include "stylesheet.h" #include "select/hash.h" #include "select/propset.h" #include "utils/parserutilserror.h" #include "utils/utils.h" /** * CSS selection context */ struct css_select_ctx { uint32_t n_sheets; /**< Number of sheets */ const css_stylesheet **sheets; /**< Array of sheets */ css_alloc alloc; /**< Allocation routine */ void *pw; /**< Client-specific private data */ }; /** * Selection state */ typedef struct css_select_state { void *node; /* Node we're selecting for */ uint64_t pseudo_element; /* Pseudo element to select for */ uint64_t pseudo_classes; /* Currently active pseudo classes */ uint64_t media; /* Currently active media types */ css_computed_style *result; /* Style to populate */ css_select_handler *handler; /* Handler functions */ void *pw; /* Client data for handlers */ uint32_t current_sheet; /* Identity of current sheet */ css_origin current_origin; /* Origin of current sheet */ uint32_t current_rule_index; /* Index of current rule */ uint32_t current_specificity; /* Specificity of current rule */ /** \todo We need a better way of knowing the number of properties * Bytecode opcodes cover 84 properties, then there's a * further 15 generated from the side bits */ /* Stylesheet identity is a monotonically increasing number based at 1 and * increasing by 1 for every applicable stylesheet encountered, including * imports. Imported sheets' identities are below that of the sheet that * imported them. */ #define N_PROPS (99) struct { uint32_t specificity; /* Specificity of property in result */ uint32_t sheet; /* Identity of applicable stylesheet */ uint32_t set : 1, /* Whether property is set in result */ origin : 2, /* Origin of property in result */ important : 1, /* Importance of property in result */ index : 16;/* Index of corresponding rule */ } props[N_PROPS]; #undef N_PROPS } css_select_state; static css_error select_from_sheet(css_select_ctx *ctx, const css_stylesheet *sheet, css_select_state *state); static css_error match_selectors_in_sheet(css_select_ctx *ctx, const css_stylesheet *sheet, css_select_state *state); static css_error match_selector_chain(css_select_ctx *ctx, const css_selector *selector, css_select_state *state, const parserutils_hash_entry *universal); static css_error match_named_combinator(css_select_ctx *ctx, css_combinator type, const parserutils_hash_entry *name, css_select_state *state, void *node, void **next_node); static css_error match_universal_combinator(css_select_ctx *ctx, css_combinator type, const css_selector *selector, css_select_state *state, void *node, void **next_node); static css_error match_details(css_select_ctx *ctx, void *node, const css_selector_detail *detail, css_select_state *state, bool *match); static css_error match_detail(css_select_ctx *ctx, void *node, const css_selector_detail *detail, css_select_state *state, bool *match); static css_error cascade_style(css_select_ctx *ctx, const css_style *style, css_select_state *state); static inline void advance_bytecode(css_style *style, uint32_t n_bytes); /* Property handlers */ #include "select/properties.c" /** * Dispatch table for properties, indexed by opcode */ static struct prop_table { css_error (*cascade)(css_select_ctx *ctx, uint32_t opv, css_style *style, css_select_state *state); css_error (*initial)(css_computed_style *style); uint32_t inherited : 1; } properties[] = { { cascade_azimuth, initial_azimuth, 1 }, { cascade_background_attachment, initial_background_attachment, 0 }, { cascade_background_color, initial_background_color, 0 }, { cascade_background_image, initial_background_image, 0 }, { cascade_background_position, initial_background_position, 0 }, { cascade_background_repeat, initial_background_repeat, 0 }, { cascade_border_collapse, initial_border_collapse, 1 }, { cascade_border_spacing, initial_border_spacing, 1 }, { cascade_border_color, initial_border_color, 0 }, { cascade_border_style, initial_border_style, 0 }, { cascade_border_width, initial_border_width, 0 }, { cascade_bottom, initial_bottom, 0 }, { cascade_caption_side, initial_caption_side, 1 }, { cascade_clear, initial_clear, 0 }, { cascade_clip, initial_clip, 0 }, { cascade_color, initial_color, 1 }, { cascade_content, initial_content, 0 }, { cascade_counter_increment, initial_counter_increment, 0 }, { cascade_counter_reset, initial_counter_reset, 0 }, { cascade_cue_after, initial_cue_after, 0 }, { cascade_cue_before, initial_cue_before, 0 }, { cascade_cursor, initial_cursor, 1 }, { cascade_direction, initial_direction, 1 }, { cascade_display, initial_display, 0 }, { cascade_elevation, initial_elevation, 1 }, { cascade_empty_cells, initial_empty_cells, 1 }, { cascade_float, initial_float, 0 }, { cascade_font_family, initial_font_family, 1 }, { cascade_font_size, initial_font_size, 1 }, { cascade_font_style, initial_font_style, 1 }, { cascade_font_variant, initial_font_variant, 1 }, { cascade_font_weight, initial_font_weight, 1 }, { cascade_height, initial_height, 0 }, { cascade_left, initial_left, 0 }, { cascade_letter_spacing, initial_letter_spacing, 1 }, { cascade_line_height, initial_line_height, 1 }, { cascade_list_style_image, initial_list_style_image, 1 }, { cascade_list_style_position, initial_list_style_position, 1 }, { cascade_list_style_type, initial_list_style_type, 1 }, { cascade_margin, initial_margin, 0 }, { cascade_max_height, initial_max_height, 0 }, { cascade_max_width, initial_max_width, 0 }, { cascade_min_height, initial_min_height, 0 }, { cascade_min_width, initial_min_width, 0 }, { cascade_orphans, initial_orphans, 1 }, { cascade_outline_color, initial_outline_color, 0 }, { cascade_outline_style, initial_outline_style, 0 }, { cascade_outline_width, initial_outline_width, 0 }, { cascade_overflow, initial_overflow, 0 }, { cascade_padding, initial_padding, 0 }, { cascade_page_break_after, initial_page_break_after, 0 }, { cascade_page_break_before, initial_page_break_before, 0 }, { cascade_page_break_inside, initial_page_break_inside, 1 }, { cascade_pause_after, initial_pause_after, 0 }, { cascade_pause_before, initial_pause_before, 0 }, { cascade_pitch_range, initial_pitch_range, 1 }, { cascade_pitch, initial_pitch, 1 }, { cascade_play_during, initial_play_during, 0 }, { cascade_position, initial_position, 0 }, { cascade_quotes, initial_quotes, 1 }, { cascade_richness, initial_richness, 1 }, { cascade_right, initial_right, 0 }, { cascade_speak_header, initial_speak_header, 1 }, { cascade_speak_numeral, initial_speak_numeral, 1 }, { cascade_speak_punctuation, initial_speak_punctuation, 1 }, { cascade_speak, initial_speak, 1 }, { cascade_speech_rate, initial_speech_rate, 1 }, { cascade_stress, initial_stress, 1 }, { cascade_table_layout, initial_table_layout, 0 }, { cascade_text_align, initial_text_align, 1 }, { cascade_text_decoration, initial_text_decoration, 0 }, { cascade_text_indent, initial_text_indent, 1 }, { cascade_text_transform, initial_text_transform, 1 }, { cascade_top, initial_top, 0 }, { cascade_unicode_bidi, initial_unicode_bidi, 0 }, { cascade_vertical_align, initial_vertical_align, 0 }, { cascade_visibility, initial_visibility, 1 }, { cascade_voice_family, initial_voice_family, 1 }, { cascade_volume, initial_volume, 1 }, { cascade_white_space, initial_white_space, 1 }, { cascade_widows, initial_widows, 1 }, { cascade_width, initial_width, 0 }, { cascade_word_spacing, initial_word_spacing, 1 }, { cascade_z_index, initial_z_index, 0 } }; /** * Create a selection context * * \param alloc Memory (de)allocation function * \param pw Client-specific private data * \param result Pointer to location to receive created context * \return CSS_OK on success, appropriate error otherwise. */ css_error css_select_ctx_create(css_alloc alloc, void *pw, css_select_ctx **result) { css_select_ctx *c; if (alloc == NULL || result == NULL) return CSS_BADPARM; c = alloc(NULL, sizeof(css_select_ctx), pw); if (c == NULL) return CSS_NOMEM; c->n_sheets = 0; c->sheets = NULL; c->alloc = alloc; c->pw = pw; *result = c; return CSS_OK; } /** * Destroy a selection context * * \param ctx The context to destroy * \return CSS_OK on success, appropriate error otherwise */ css_error css_select_ctx_destroy(css_select_ctx *ctx) { if (ctx == NULL) return CSS_BADPARM; if (ctx->sheets != NULL) ctx->alloc(ctx->sheets, 0, ctx->pw); ctx->alloc(ctx, 0, ctx->pw); return CSS_OK; } /** * Append a stylesheet to a selection context * * \param ctx The context to append to * \param sheet The sheet to append * \return CSS_OK on success, appropriate error otherwise */ css_error css_select_ctx_append_sheet(css_select_ctx *ctx, const css_stylesheet *sheet) { if (ctx == NULL || sheet == NULL) return CSS_BADPARM; return css_select_ctx_insert_sheet(ctx, sheet, ctx->n_sheets); } /** * Insert a stylesheet into a selection context * * \param ctx The context to insert into * \param sheet Sheet to insert * \param index Index in context to insert sheet * \return CSS_OK on success, appropriate error otherwise */ css_error css_select_ctx_insert_sheet(css_select_ctx *ctx, const css_stylesheet *sheet, uint32_t index) { const css_stylesheet **temp; if (ctx == NULL || sheet == NULL) return CSS_BADPARM; /* Index must be in the range [0, n_sheets] * The latter being equivalent to append */ if (index > ctx->n_sheets) return CSS_INVALID; temp = ctx->alloc(ctx->sheets, (ctx->n_sheets + 1) * sizeof(css_stylesheet *), ctx->pw); if (temp == NULL) return CSS_NOMEM; ctx->sheets = temp; if (index < ctx->n_sheets) { memmove(&ctx->sheets[index + 1], &ctx->sheets[index], (ctx->n_sheets - index) * sizeof(css_stylesheet *)); } ctx->sheets[index] = sheet; ctx->n_sheets++; return CSS_OK; } /** * Remove a sheet from a selection context * * \param ctx The context to remove from * \param sheet Sheet to remove * \return CSS_OK on success, appropriate error otherwise */ css_error css_select_ctx_remove_sheet(css_select_ctx *ctx, const css_stylesheet *sheet) { uint32_t index; if (ctx == NULL || sheet == NULL) return CSS_BADPARM; for (index = 0; index < ctx->n_sheets; index++) { if (ctx->sheets[index] == sheet) break; } if (index == ctx->n_sheets) return CSS_INVALID; memmove(&ctx->sheets[index], &ctx->sheets[index + 1], (ctx->n_sheets - index) * sizeof(css_stylesheet *)); ctx->n_sheets--; return CSS_OK; } /** * Count the number of top-level sheets in a selection context * * \param ctx Context to consider * \param count Pointer to location to receive count of sheets * \return CSS_OK on success, appropriate error otherwise */ css_error css_select_ctx_count_sheets(css_select_ctx *ctx, uint32_t *count) { if (ctx == NULL || count == NULL) return CSS_BADPARM; *count = ctx->n_sheets; return CSS_OK; } /** * Retrieve a sheet from a selection context * * \param ctx Context to look in * \param index Index in context to look * \param sheet Pointer to location to receive sheet * \return CSS_OK on success, appropriate error otherwise */ css_error css_select_ctx_get_sheet(css_select_ctx *ctx, uint32_t index, const css_stylesheet **sheet) { if (ctx == NULL || sheet == NULL) return CSS_BADPARM; if (index > ctx->n_sheets) return CSS_INVALID; *sheet = ctx->sheets[index]; return CSS_OK; } /** * Select a style for the given node * * \param ctx Selection context to use * \param node Node to select style for * \param pseudo_element Pseudo element to select for, instead * \param pseudo_classes Currently active pseudo classes * \param media Currently active media types * \param result Pointer to style to populate * \param handler Dispatch table of handler functions * \param pw Client-specific private data for handler functions * \return CSS_OK on success, appropriate error otherwise. * * In computing the style, no reference is made to the parent node's * style. Therefore, the resultant computed style is not ready for * immediate use, as some properties may be marked as inherited. * Use css_computed_style_compose() to obtain a fully computed style. * * This two-step approach to style computation is designed to allow * the client to store the partially computed style and efficiently * update the fully computed style for a node when layout changes. */ css_error css_select_style(css_select_ctx *ctx, void *node, uint64_t pseudo_element, uint64_t pseudo_classes, uint64_t media, css_computed_style *result, css_select_handler *handler, void *pw) { uint32_t i; css_error error; css_select_state state; if (ctx == NULL || node == NULL || result == NULL) return CSS_BADPARM; /* Set up the selection state */ memset(&state, 0, sizeof(css_select_state)); state.node = node; state.pseudo_element = pseudo_element; state.pseudo_classes = pseudo_classes; state.media = media; state.result = result; state.handler = handler; state.pw = pw; /* Iterate through the top-level stylesheets, selecting styles * from those which apply to our current media requirements */ for (i = 0; i < ctx->n_sheets; i++) { if ((ctx->sheets[i]->media & media) != 0) { error = select_from_sheet(ctx, ctx->sheets[i], &state); if (error != CSS_OK) return error; } } /* Finally, fix up any remaining unset properties. * Those properties which are inherited need to be set as inherit. * Those which are not inherited need to be set to their default value. */ /** \todo fixup unset properties */ return CSS_OK; } /****************************************************************************** * Selection engine internals below here * ******************************************************************************/ css_error select_from_sheet(css_select_ctx *ctx, const css_stylesheet *sheet, css_select_state *state) { const css_stylesheet *s = sheet; const css_rule *rule = s->rule_list; do { /* Find first non-charset rule, if we're at the list head */ if (rule == s->rule_list) { for (; rule != NULL; rule = rule->next) { if (rule->type != CSS_RULE_CHARSET) break; } } if (rule != NULL && rule->type == CSS_RULE_IMPORT) { /* Current rule is an import */ const css_rule_import *import = (const css_rule_import *) rule; if (import->sheet != NULL && (import->sheet->media & state->media) != 0) { /* It's applicable, so process it */ s = import->sheet; rule = s->rule_list; } else { /* Not applicable; skip over it */ rule = rule->next; } } else { /* Gone past import rules in this sheet */ css_error error; /* Process this sheet */ state->current_sheet++; state->current_origin = s->origin; error = match_selectors_in_sheet(ctx, s, state); if (error != CSS_OK) return error; /* Find next sheet to process */ if (s->ownerRule != NULL) { s = s->ownerRule->parent; rule = s->ownerRule->next; } else { s = NULL; } } } while (s != NULL); return CSS_OK; } css_error match_selectors_in_sheet(css_select_ctx *ctx, const css_stylesheet *sheet, css_select_state *state) { const parserutils_hash_entry *universal; const parserutils_hash_entry *element; const css_selector **selectors; const uint8_t *name; size_t len; parserutils_error perror; css_error error; /* Get node's name */ error = state->handler->node_name(state->pw, state->node, &name, &len); if (error != CSS_OK) return error; /* Intern it */ perror = parserutils_hash_insert(sheet->dictionary, name, len, &element); if (perror != PARSERUTILS_OK) return css_error_from_parserutils_error(perror); /* Intern universal selector string */ perror = parserutils_hash_insert(sheet->dictionary, (const uint8_t *) "*", 1, &universal); if (perror != PARSERUTILS_OK) return css_error_from_parserutils_error(perror); /* Find hash chain that applies to current node */ error = css_selector_hash_find(sheet->selectors, element, &selectors); if (error != CSS_OK) return error; /* Process any matching selectors */ while (*selectors != NULL) { error = match_selector_chain(ctx, *selectors, state, universal); if (error != CSS_OK) return error; error = css_selector_hash_iterate(sheet->selectors, selectors, &selectors); if (error != CSS_OK) return error; } /* Find hash chain for universal selector */ error = css_selector_hash_find(sheet->selectors, universal, &selectors); if (error != CSS_OK) return error; /* Process any matching selectors */ while (*selectors != NULL) { error = match_selector_chain(ctx, *selectors, state, universal); if (error != CSS_OK) return error; error = css_selector_hash_iterate(sheet->selectors, selectors, &selectors); if (error != CSS_OK) return error; } return CSS_OK; } css_error match_selector_chain(css_select_ctx *ctx, const css_selector *selector, css_select_state *state, const parserutils_hash_entry *universal) { const css_selector *s = selector; void *node = state->node; css_error error; do { void *next_node = NULL; const css_selector_detail *detail = &s->data; bool match = false; /* First, consider any named combinator on this selector */ if (s->data.comb != CSS_COMBINATOR_NONE && s->combinator->data.name != universal) { error = match_named_combinator(ctx, s->data.comb, s->combinator->data.name, state, node, &next_node); if (error != CSS_OK) return error; /* No match for combinator, so reject selector chain */ if (next_node == NULL) return CSS_OK; } /* Now match details on this selector */ error = match_details(ctx, node, detail, state, &match); if (error != CSS_OK) return error; /* Details don't match, so reject selector chain */ if (match == false) return CSS_OK; /* If we had a universal combinator, then consider that */ if (s->data.comb != CSS_COMBINATOR_NONE && s->combinator->data.name == universal) { error = match_universal_combinator(ctx, s->data.comb, s->combinator, state, node, &next_node); if (error != CSS_OK) return error; /* No match for combinator, so reject selector chain */ if (next_node == NULL) return CSS_OK; } /* Details matched, so progress to combining selector */ s = s->combinator; node = next_node; } while (s != NULL); /* If we got here, then the entire selector chain matched, so cascade */ state->current_rule_index = selector->rule->index; state->current_specificity = selector->specificity; return cascade_style(ctx, ((css_rule_selector *) selector->rule)->style, state); } css_error match_named_combinator(css_select_ctx *ctx, css_combinator type, const parserutils_hash_entry *name, css_select_state *state, void *node, void **next_node) { css_error error; UNUSED(ctx); switch (type) { case CSS_COMBINATOR_ANCESTOR: error = state->handler->named_ancestor_node(state->pw, node, name->data, name->len, next_node); if (error != CSS_OK) return error; break; case CSS_COMBINATOR_PARENT: error = state->handler->named_parent_node(state->pw, node, name->data, name->len, next_node); if (error != CSS_OK) return error; break; case CSS_COMBINATOR_SIBLING: error = state->handler->named_sibling_node(state->pw, node, name->data, name->len, next_node); if (error != CSS_OK) return error; break; case CSS_COMBINATOR_NONE: break; } return CSS_OK; } css_error match_universal_combinator(css_select_ctx *ctx, css_combinator type, const css_selector *selector, css_select_state *state, void *node, void **next_node) { const css_selector_detail *detail = &selector->data; void *n = node; css_error error; do { bool match = false; /* Find candidate node */ switch (type) { case CSS_COMBINATOR_ANCESTOR: case CSS_COMBINATOR_PARENT: error = state->handler->parent_node(state->pw, n, &n); if (error != CSS_OK) return error; break; case CSS_COMBINATOR_SIBLING: error = state->handler->sibling_node(state->pw, n, &n); if (error != CSS_OK) return error; break; case CSS_COMBINATOR_NONE: break; } /* Match its details */ error = match_details(ctx, n, detail, state, &match); if (error != CSS_OK) return error; /* If we found a match, use it */ if (match == true) break; /* Wanted the parent, but it didn't match, so stop looking */ if (type == CSS_COMBINATOR_PARENT) n = NULL; } while (n != NULL); *next_node = n; return CSS_OK; } css_error match_details(css_select_ctx *ctx, void *node, const css_selector_detail *detail, css_select_state *state, bool *match) { css_error error; /** \todo Some details are easier to test than others (e.g. dashmatch * actually requires looking at data rather than simply comparing * pointers). Should we consider sorting the detail list such that the * simpler details come first (and thus the expensive match routines * can be avoided unless absolutely necessary)? */ while (detail->next != 0) { /* Don't bother with the first detail, as it's the * element selector */ detail++; error = match_detail(ctx, node, detail, state, match); if (error != CSS_OK) return error; /* Detail doesn't match, so reject selector chain */ if (*match == false) return CSS_OK; } return CSS_OK; } css_error match_detail(css_select_ctx *ctx, void *node, const css_selector_detail *detail, css_select_state *state, bool *match) { css_error error = CSS_OK; UNUSED(ctx); switch (detail->type) { case CSS_SELECTOR_CLASS: error = state->handler->node_has_class(state->pw, node, detail->name->data, detail->name->len, match); break; case CSS_SELECTOR_ID: error = state->handler->node_has_id(state->pw, node, detail->name->data, detail->name->len, match); break; case CSS_SELECTOR_PSEUDO_CLASS: /** \todo pseudo classes */ break; case CSS_SELECTOR_PSEUDO_ELEMENT: /** \todo pseudo elements */ break; case CSS_SELECTOR_ATTRIBUTE: error = state->handler->node_has_attribute(state->pw, node, detail->name->data, detail->name->len, match); break; case CSS_SELECTOR_ATTRIBUTE_EQUAL: error = state->handler->node_has_attribute_equal(state->pw, node, detail->name->data, detail->name->len, detail->value->data, detail->value->len, match); break; case CSS_SELECTOR_ATTRIBUTE_DASHMATCH: error = state->handler->node_has_attribute_dashmatch(state->pw, node, detail->name->data, detail->name->len, detail->value->data, detail->value->len, match); break; case CSS_SELECTOR_ATTRIBUTE_INCLUDES: error = state->handler->node_has_attribute_includes(state->pw, node, detail->name->data, detail->name->len, detail->value->data, detail->value->len, match); break; } return error; } css_error cascade_style(css_select_ctx *ctx, const css_style *style, css_select_state *state) { css_style s = *style; while (s.length > 0) { opcode op; css_error error; uint32_t opv = *((uint32_t *) s.bytecode); advance_bytecode(&s, sizeof(opv)); op = getOpcode(opv); error = properties[op].cascade(ctx, opv, &s, state); if (error != CSS_OK) return error; } return CSS_OK; } void advance_bytecode(css_style *style, uint32_t n_bytes) { style->length -= n_bytes; style->bytecode = ((uint8_t *) style->bytecode) + n_bytes; }