lws-html.h

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/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 - 2022 Andy Green <andy@warmcat.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Extremely Lightweight HTML5 Stream Parser, same approach as lecp but for
 * html5.
 */
 
#if !defined(LHP_MAX_ELEMS_NEST)
#define LHP_MAX_ELEMS_NEST              128
#endif
#if !defined(LHP_MAX_DEPTH)
#define LHP_MAX_DEPTH                   64
#endif
#if !defined(LHP_STRING_CHUNK)
#define LHP_STRING_CHUNK                2048
#endif
/*
 * How many of an element's closed earlier siblings are remembered (their
 * attributes) so that the ~ and + selector combinators and :first-child can
 * be evaluated.  Costs the attribute storage of that many elements per open
 * level.
 */
#if !defined(LHP_SIBLING_HISTORY)
#if defined(LWS_PLAT_FREERTOS) || defined(LWS_PLAT_BAREMETAL)
#define LHP_SIBLING_HISTORY             2
#else
#define LHP_SIBLING_HISTORY             8
#endif
#endif
 
enum lhp_callbacks {
 
        LHPCB_ERR_ATTRIB_SYNTAX         = -5,
        LHPCB_ERR_ATTRIB_LEN            = -4,
        LHPCB_ERR_OOM                   = -3,
        LHPCB_ERR_ELEM_DEPTH            = -2,
        LHPCB_CONTINUE                  = -1,
 
        LHPCB_CONSTRUCTED               = 0,
        LHPCB_DESTRUCTED                = 1,
 
        LHPCB_COMPLETE                  = 2,
        LHPCB_FAILED                    = 3,
 
        LHPCB_ELEMENT_START             = 4,    /* reported at end of <> */
        LHPCB_ELEMENT_END               = 5,
 
        LHPCB_CONTENT                   = 6,
 
        LHPCB_COMMENT                   = 7,
};
 
/*
 * CSS v2.1 full property set, taken from
 *
 * https://www.w3.org/TR/CSS21/propidx.html
 */
 
typedef enum lcsp_props {
        LCSP_PROP_AZIMUTH,
        LCSP_PROP_BACKGROUND_ATTACHMENT,
        LCSP_PROP_BACKGROUND_COLOR,
        LCSP_PROP_BACKGROUND_IMAGE,
        LCSP_PROP_BACKGROUND_POSITION,
        LCSP_PROP_BACKGROUND_REPEAT,
        LCSP_PROP_BACKGROUND_SIZE,
        LCSP_PROP_BACKGROUND,
        LCSP_PROP_BORDER_COLLAPSE,
        LCSP_PROP_BORDER_COLOR,
        LCSP_PROP_BORDER_SPACING,
        LCSP_PROP_BORDER_STYLE,
        LCSP_PROP_BORDER_TOP,
        LCSP_PROP_BORDER_RIGHT,
        LCSP_PROP_BORDER_BOTTOM,
        LCSP_PROP_BORDER_LEFT,
        LCSP_PROP_BORDER_TOP_COLOR,
        LCSP_PROP_BORDER_RIGHT_COLOR,
        LCSP_PROP_BORDER_BOTTOM_COLOR,
        LCSP_PROP_BORDER_LEFT_COLOR,
        LCSP_PROP_BORDER_TOP_STYLE,
        LCSP_PROP_BORDER_RIGHT_STYLE,
        LCSP_PROP_BORDER_BOTTOM_STYLE,
        LCSP_PROP_BORDER_LEFT_STYLE,
        LCSP_PROP_BORDER_TOP_WIDTH,
        LCSP_PROP_BORDER_RIGHT_WIDTH,
        LCSP_PROP_BORDER_BOTTOM_WIDTH,
        LCSP_PROP_BORDER_LEFT_WIDTH,
        LCSP_PROP_BORDER_WIDTH,
        LCSP_PROP_BORDER_TOP_LEFT_RADIUS,
        LCSP_PROP_BORDER_TOP_RIGHT_RADIUS,
        LCSP_PROP_BORDER_BOTTOM_LEFT_RADIUS,
        LCSP_PROP_BORDER_BOTTOM_RIGHT_RADIUS,
        LCSP_PROP_BORDER_RADIUS,
        LCSP_PROP_BORDER,
        LCSP_PROP_BOTTOM,
        LCSP_PROP_BOX_SIZING,
        LCSP_PROP_CAPTION_SIDE,
        LCSP_PROP_CLEAR,
        LCSP_PROP_CLIP,
        LCSP_PROP_COLOR,
        LCSP_PROP_CONTENT,
        LCSP_PROP_COUNTER_INCREMENT,
        LCSP_PROP_COUNTER_RESET,
        LCSP_PROP_CUE_AFTER,
        LCSP_PROP_CUE_BEFORE,
        LCSP_PROP_CUE,
        LCSP_PROP_CURSOR,
        LCSP_PROP_DIRECTION,
        LCSP_PROP_DISPLAY,
        LCSP_PROP_ELEVATION,
        LCSP_PROP_EMPTY_CELLS,
        LCSP_PROP_FLOAT,
        LCSP_PROP_FONT_FAMILY,
        LCSP_PROP_FONT_SIZE,
        LCSP_PROP_FONT_STYLE,
        LCSP_PROP_FONT_VARAIANT,
        LCSP_PROP_FONT_WEIGHT,
        LCSP_PROP_FONT,
        LCSP_PROP_HEIGHT,
        LCSP_PROP_LEFT,
        LCSP_PROP_LETTER_SPACING,
        LCSP_PROP_LINE_HEIGHT,
        LCSP_PROP_LIST_STYLE_IMAGE,
        LCSP_PROP_LIST_STYLE_POSITION,
        LCSP_PROP_LIST_STYLE_TYPE,
        LCSP_PROP_LIST_STYLE,
        LCSP_PROP_MARGIN_RIGHT,
        LCSP_PROP_MARGIN_LEFT,
        LCSP_PROP_MARGIN_TOP,
        LCSP_PROP_MARGIN_BOTTOM,
        LCSP_PROP_MARGIN,
        LCSP_PROP_MAX_HEIGHT,
        LCSP_PROP_MAX_WIDTH,
        LCSP_PROP_MIN_HEIGHT,
        LCSP_PROP_MIN_WIDTH,
        LCSP_PROP_ORPHANS,
        LCSP_PROP_OUTLINE_COLOR,
        LCSP_PROP_OUTLINE_STYLE,
        LCSP_PROP_OUTLINE_WIDTH,
        LCSP_PROP_OUTLINE,
        LCSP_PROP_OVERFLOW,
        LCSP_PROP_PADDING_TOP,
        LCSP_PROP_PADDING_RIGHT,
        LCSP_PROP_PADDING_BOTTOM,
        LCSP_PROP_PADDING_LEFT,
        LCSP_PROP_PADDING,
        LCSP_PROP_PAGE_BREAK_AFTER,
        LCSP_PROP_PAGE_BREAK_BEFORE,
        LCSP_PROP_PAGE_BREAK_INSIDE,
        LCSP_PROP_PAUSE_AFTER,
        LCSP_PROP_PAUSE_BEFORE,
        LCSP_PROP_PAUSE,
        LCSP_PROP_PITCH_RANGE,
        LCSP_PROP_PITCH,
        LCSP_PROP_PLAY_DURING,
        LCSP_PROP_POSITION,
        LCSP_PROP_QUOTES,
        LCSP_PROP_RICHNESS,
        LCSP_PROP_RIGHT,
        LCSP_PROP_SPEAK_HEADER,
        LCSP_PROP_SPEAK_NUMERAL,
        LCSP_PROP_SPEAK_PUNCTUATION,
        LCSP_PROP_SPEAK,
        LCSP_PROP_SPEECH_RATE,
        LCSP_PROP_STRESS,
        LCSP_PROP_TABLE_LAYOUT,
        LCSP_PROP_TEXT_ALIGN,
        LCSP_PROP_TEXT_DECORATION,
        LCSP_PROP_TEXT_INDENT,
        LCSP_PROP_TEXT_TRANSFORM,
        LCSP_PROP_TOP,
        LCSP_PROP_UNICODE_BIDI,
        LCSP_PROP_VERTICAL_ALIGN,
        LCSP_PROP_VISIBILITY,
        LCSP_PROP_VOICE_FAMILY,
        LCSP_PROP_VOLUME,
        LCSP_PROP_WHITE_SPACE,
        LCSP_PROP_WIDOWS,
        LCSP_PROP_WIDTH,
        LCSP_PROP_WORD_SPACING,
        LCSP_PROP_Z_INDEX,
 
        /* appended: the lextable index is the enum value */
        LCSP_PROP_OPACITY,
        LCSP_PROP_FLEX,
        LCSP_PROP_FLEX_DIRECTION,
        LCSP_PROP_FLEX_GROW,
        LCSP_PROP_FLEX_SHRINK,
        LCSP_PROP_FLEX_BASIS,
        LCSP_PROP_FLEX_WRAP,
        LCSP_PROP_ALIGN_ITEMS,
        LCSP_PROP_ALIGN_SELF,
        LCSP_PROP_JUSTIFY_CONTENT,
        LCSP_PROP_GAP,
        LCSP_PROP_COLUMN_GAP,
        LCSP_PROP_ROW_GAP,
 
        /* logical properties, mapped to the physical sides (ltr, horizontal) */
        LCSP_PROP_MARGIN_INLINE,
        LCSP_PROP_MARGIN_INLINE_START,
        LCSP_PROP_MARGIN_INLINE_END,
        LCSP_PROP_MARGIN_BLOCK,
        LCSP_PROP_MARGIN_BLOCK_START,
        LCSP_PROP_MARGIN_BLOCK_END,
        LCSP_PROP_PADDING_INLINE,
        LCSP_PROP_PADDING_INLINE_START,
        LCSP_PROP_PADDING_INLINE_END,
        LCSP_PROP_PADDING_BLOCK,
        LCSP_PROP_PADDING_BLOCK_START,
        LCSP_PROP_PADDING_BLOCK_END,
        LCSP_PROP_INSET,
        LCSP_PROP_INSET_INLINE,
        LCSP_PROP_INSET_INLINE_START,
        LCSP_PROP_INSET_INLINE_END,
        LCSP_PROP_INSET_BLOCK,
        LCSP_PROP_INSET_BLOCK_START,
        LCSP_PROP_INSET_BLOCK_END,
 
        LCSP_PROP__COUNT /* always last */
} lcsp_props_t;
 
/*
 * Indexes for the well-known property values
 */
 
typedef enum {
        LCSP_PROPVAL_ABOVE,
        LCSP_PROPVAL_ABSOLUTE,
        LCSP_PROPVAL_ALWAYS,
        LCSP_PROPVAL_ARMENIAN,
        LCSP_PROPVAL_AUTO,
        LCSP_PROPVAL_AVOID,
        LCSP_PROPVAL_BASELINE,
        LCSP_PROPVAL_BEHIND,
        LCSP_PROPVAL_BELOW,
        LCSP_PROPVAL_BIDI_OVERRIDE,
        LCSP_PROPVAL_BLINK,
        LCSP_PROPVAL_BLOCK,
        LCSP_PROPVAL_BOLD,
        LCSP_PROPVAL_BOLDER,
        LCSP_PROPVAL_BORDER_BOX,
        LCSP_PROPVAL_BOTH,
        LCSP_PROPVAL_BOTTOM,
        LCSP_PROPVAL_CAPITALIZE,
        LCSP_PROPVAL_CAPTION,
        LCSP_PROPVAL_CENTER,
        LCSP_PROPVAL_CIRCLE,
        LCSP_PROPVAL_CLOSE_QUOTE,
        LCSP_PROPVAL_CODE,
        LCSP_PROPVAL_COLLAPSE,
        LCSP_PROPVAL_CONTENT_BOX,
        LCSP_PROPVAL_CONTINUOUS,
        LCSP_PROPVAL_CROSSHAIR,
        LCSP_PROPVAL_DECIMAL_LEADING_ZERO,
        LCSP_PROPVAL_DECIMAL,
        LCSP_PROPVAL_DIGITS,
        LCSP_PROPVAL_DISC,
        LCSP_PROPVAL_EMBED,
        LCSP_PROPVAL_E_RESIZE,
        LCSP_PROPVAL_FIXED,
        LCSP_PROPVAL_GEORGIAN,
        LCSP_PROPVAL_HELP,
        LCSP_PROPVAL_HIDDEN,
        LCSP_PROPVAL_HIDE,
        LCSP_PROPVAL_HIGH,
        LCSP_PROPVAL_HIGHER,
        LCSP_PROPVAL_ICON,
        LCSP_PROPVAL_INHERIT,
        LCSP_PROPVAL_INLINE,
        LCSP_PROPVAL_INLINE_BLOCK,
        LCSP_PROPVAL_INLINE_TABLE,
        LCSP_PROPVAL_INVERT,
        LCSP_PROPVAL_ITALIC,
        LCSP_PROPVAL_JUSTIFY,
        LCSP_PROPVAL_LEFT,
        LCSP_PROPVAL_LIGHTER,
        LCSP_PROPVAL_LINE_THROUGH,
        LCSP_PROPVAL_LIST_ITEM,
        LCSP_PROPVAL_LOW,
        LCSP_PROPVAL_LOWER,
        LCSP_PROPVAL_LOWER_ALPHA,
        LCSP_PROPVAL_LOWERCASE,
        LCSP_PROPVAL_LOWER_GREEK,
        LCSP_PROPVAL_LOWER_LATIN,
        LCSP_PROPVAL_LOWER_ROMAN,
        LCSP_PROPVAL_LTR,
        LCSP_PROPVAL_MENU,
        LCSP_PROPVAL_MESSAGE_BOX,
        LCSP_PROPVAL_MIDDLE,
        LCSP_PROPVAL_MIX,
        LCSP_PROPVAL_MOVE,
        LCSP_PROPVAL_NE_RESIZE,
        LCSP_PROPVAL_NO_CLOSE_QUOTE,
        LCSP_PROPVAL_NONE,
        LCSP_PROPVAL_NO_OPEN_QUOTE,
        LCSP_PROPVAL_NO_REPEAT,
        LCSP_PROPVAL_NORMAL,
        LCSP_PROPVAL_NOWRAP,
        LCSP_PROPVAL_N_RESIZE,
        LCSP_PROPVAL_NW_RESIZE,
        LCSP_PROPVAL_OBLIQUE,
        LCSP_PROPVAL_ONCE,
        LCSP_PROPVAL_OPEN_QUOTE,
        LCSP_PROPVAL_OUTSIDE,
        LCSP_PROPVAL_OVERLINE,
        LCSP_PROPVAL_POINTER,
        LCSP_PROPVAL_PRE,
        LCSP_PROPVAL_PRE_LINE,
        LCSP_PROPVAL_PRE_WRAP,
        LCSP_PROPVAL_PROGRESS,
        LCSP_PROPVAL_RELATIVE,
        LCSP_PROPVAL_REPEAT,
        LCSP_PROPVAL_REPEAT_X,
        LCSP_PROPVAL_REPEAT_Y,
        LCSP_PROPVAL_RIGHT,
        LCSP_PROPVAL_RTL,
        LCSP_PROPVAL_SCROLL,
        LCSP_PROPVAL_SEPARATE,
        LCSP_PROPVAL_SE_RESIZE,
        LCSP_PROPVAL_SHOW,
        LCSP_PROPVAL_SILENT,
        LCSP_PROPVAL_SMALL_CAPS,
        LCSP_PROPVAL_SMALL_CAPTION,
        LCSP_PROPVAL_SPELL_OUT,
        LCSP_PROPVAL_SQUARE,
        LCSP_PROPVAL_S_RESIZE,
        LCSP_PROPVAL_STATIC,
        LCSP_PROPVAL_STATUS_BAR,
        LCSP_PROPVAL_SUB,
        LCSP_PROPVAL_SUPER,
        LCSP_PROPVAL_SW_RESIZE,
        LCSP_PROPVAL_TABLE,
        LCSP_PROPVAL_TABLE_CAPTION,
        LCSP_PROPVAL_TABLE_CELL,
        LCSP_PROPVAL_TABLE_COLUMN,
        LCSP_PROPVAL_TABLE_COLUMN_GROUP,
        LCSP_PROPVAL_TABLE_FOOTER_GROUP,
        LCSP_PROPVAL_TABLE_HEADER_GROUP,
        LCSP_PROPVAL_TABLE_ROW,
        LCSP_PROPVAL_TABLE_ROW_GROUP,
        LCSP_PROPVAL_TEXT_BOTTOM,
        LCSP_PROPVAL_TEXT_TOP,
        LCSP_PROPVAL_TEXT,
        LCSP_PROPVAL_TOP,
        LCSP_PROPVAL_TRANSPARENT,
        LCSP_PROPVAL_UNDERLINE,
        LCSP_PROPVAL_UPPER_ALPHA,
        LCSP_PROPVAL_UPPERCASE,
        LCSP_PROPVAL_UPPER_LATIN,
        LCSP_PROPVAL_UPPER_ROMAN,
        LCSP_PROPVAL_VISIBLE,
        LCSP_PROPVAL_WAIT,
        LCSP_PROPVAL_W_RESIZE,
 
        /* appended: the lextable index is the enum value */
        LCSP_PROPVAL_FLEX,
        LCSP_PROPVAL_INLINE_FLEX,
        LCSP_PROPVAL_ROW,
        LCSP_PROPVAL_COLUMN,
        LCSP_PROPVAL_SPACE_BETWEEN,
        LCSP_PROPVAL_SPACE_AROUND,
        LCSP_PROPVAL_SPACE_EVENLY,
        LCSP_PROPVAL_FLEX_START,
        LCSP_PROPVAL_FLEX_END,
        LCSP_PROPVAL_STRETCH,
        LCSP_PROPVAL_WRAP,
        LCSP_PROPVAL_START,
        LCSP_PROPVAL_END,
        LCSP_PROPVAL_COVER,
        LCSP_PROPVAL_CONTAIN,
        LCSP_PROPVAL_NOT_ALLOWED,
        LCSP_PROPVAL_DEFAULT,
 
        LCSP_PROPVAL__COUNT /* always last */
} lcsp_propvals_t;
 
struct lhp_ctx;
typedef lws_stateful_ret_t (*lhp_callback)(struct lhp_ctx *ctx, char reason);
 
/* html attribute */
 
typedef struct lhp_atr {
        lws_dll2_t              list;
        size_t                  name_len;       /* 0 if it is elem tag */
        size_t                  value_len;
 
        /* name+NUL then value+NUL follow */
} lhp_atr_t;
 
/* a closed element remembered on its parent for sibling selectors */
 
typedef struct lhp_sib {
        lws_dll2_t              list;   /* parent's sibs, newest last */
        lws_dll2_owner_t        atr;    /* lhp_atr_t moved from the level */
} lhp_sib_t;
 
/*
 * In order to lay out the table, we have to incrementally adjust all foregoing
 * DLOs as newer cells change the situation.  So we have to keep track of all
 * cell DLOs in a stack of tables until it's all done.
 */
 
typedef struct {
        lws_dll2_t                      list; /* ps->table_cols */
 
        lws_dll2_owner_t                row_dlos; /* lws_dlo_t in column */
 
        lws_fx_t                        height; /* currently computed row height */
} lhp_table_row_t;
 
typedef struct {
        lws_dll2_t                      list; /* ps->table_cols */
 
        lws_dll2_owner_t                col_dlos; /* lws_dlo_t in column */
 
        lws_fx_t                        width; /* computed column width */
        lws_fx_t                        min_w; /* widest min-content cell */
        lws_fx_t                        max_w; /* widest max-content cell */
} lhp_table_col_t;
 
struct lcsp_atr;
struct lcsp_match;
 
#define CCPAS_TOP 0
#define CCPAS_RIGHT 1
#define CCPAS_BOTTOM 2
#define CCPAS_LEFT 3
 
typedef struct lhp_pstack {
        lws_dll2_t                      list;
        void                            *user;  /* private to the stack level */
        lhp_callback                    cb;
 
        /* static: x,y: offset from parent, w,h: surface size of this object */
        lws_box_t                       drt;
 
        /*
         * Layout state for an element that is a block container (has a dlo
         * and lays its children out inside it).  Coordinates are relative to
         * our dlo box: the content area starts at (ox, oy) and is cw wide;
         * (curx, cury) is the inline cursor inside it, cury being the top of
         * the line being built.
         */
        lws_fx_t                        ox;
        lws_fx_t                        oy;
        lws_fx_t                        cw;
        lws_fx_t                        abs_h; /* an absolute box's percentage
                                                * height, resolved against its
                                                * positioned ancestor's padding
                                                * box at open */
        lws_fx_t                        abs_bot; /* an absolute box anchored by
                                                  * bottom: the y of its bottom
                                                  * margin edge */
        lws_fx_t                        curx;
        lws_fx_t                        cury;
 
        lws_fx_t                        line_h;  /* tallest non-text item on line */
        lws_dlo_t                       *line_first; /* first dlo of the open line */
        int16_t                         line_asc; /* max ascent above baseline on line */
        int16_t                         line_desc; /* max descent below baseline on line */
        int16_t                         last_base; /* baseline of our last line, from
                                                    * our box top (valid if has_base) */
 
        lws_fx_t                        maxc;    /* max-content width so far */
        lws_fx_t                        minc;    /* min-content width so far */
        lws_fx_t                        nowrap;  /* width of current line if unwrapped */
        lws_fx_t                        rfloat_w; /* width taken by right floats on line */
        lws_fx_t                        pend_mb; /* last block child's bottom margin */
        int32_t                         abs_y;   /* approx surface y of our box top */
        uint16_t                        idx;     /* list item / table cell counter */
 
        lws_dll2_owner_t                atr; /* lhp_atr_t */
        lws_dll2_owner_t                sibs; /* lhp_sib_t: our closed children */
 
        const lws_display_font_t        *f;
 
        const struct lcsp_atr           *css_background_color;
        const struct lcsp_atr           *css_color;
 
        const struct lcsp_atr           *css_position;
        const struct lcsp_atr           *css_display;
        const struct lcsp_atr           *css_width;
        const struct lcsp_atr           *css_height;
        const struct lcsp_atr           *css_text_indent;
        const struct lcsp_atr           *css_box_sizing;
 
        /*
         * Stanzas whose selector matched this element with a :before / :after
         * pseudo-element suffix: a generated box for each is added when the
         * element closes
         */
        struct lcsp_stanza              *pseudo_before;
        struct lcsp_stanza              *pseudo_after;
 
        const struct lcsp_atr           *css_border_radius[4];
 
        const struct lcsp_atr           *css_pos[4];
        const struct lcsp_atr           *css_margin[4];
        const struct lcsp_atr           *css_padding[4];
 
        /*
         * css resolution for this element: the stanzas whose selectors matched
         * it, lowest precedence first, plus the parsed style="" attribute (in
         * styleac) as the highest.  Properties absent here are looked up on
         * the parent if the property inherits, else take their initial value.
         */
        struct lcsp_match               *matched;
        struct lwsac                    *styleac;
        lws_fx_t                        font_size; /* computed font-size, px */
        uint16_t                        nmatched;
 
        uint8_t                         is_block:1; /* we are a block container */
        uint8_t                         is_table:1;
        uint8_t                         is_row:1;
        uint8_t                         is_cell:1;
        uint8_t                         is_inline:1; /* style scope only, no box */
        uint8_t                         is_ilevel:1; /* inline-level box (inline-block) */
        uint8_t                         is_abs:1;    /* absolutely positioned */
        uint8_t                         is_float:1;
        uint8_t                         is_float_right:1;
        uint8_t                         is_flex:1;   /* row flex container */
        uint8_t                         is_flex_item:1;
        uint8_t                         flex_wrap:1;
        uint8_t                         shrink:1;    /* width decided by content at close */
        uint8_t                         in_shrink:1; /* auto width inside a shrinking container */
        uint8_t                         has_line:1;  /* a line is being built */
        uint8_t                         has_base:1;  /* last_base is valid */
        uint8_t                         last_space:1; /* line so far ends with a space */
        uint8_t                         explicit_w:1;
        uint8_t                         explicit_h:1;
        uint8_t                         abs_h_set:1; /* abs_h is the resolved
                                                      * percentage height */
        uint8_t                         abs_minh_set:1; /* ... or min-height */
        uint8_t                         abs_bot_set:1; /* abs_bot places us at
                                                        * close */
        uint8_t                         abs_stretch_set:1; /* top + bottom stretch,
                                                            * abs_bot the bottom
                                                            * offset, sized when
                                                            * the ancestor closes */
        uint8_t                         css_resolved:1;
        uint8_t                         in_body:1;
        uint8_t                         hidden:1; /* display: none on us or an ancestor */
        uint8_t                         ti_done:1; /* applied our text-indent already */
 
        /* user layout owns these after initial values set */
 
        lws_dlo_t                       *dlo;
        const lws_display_font_t        *font;
 
        /*
         * A css background-image on this element: its dlo is created when
         * the element is parsed, before the layout has made the element's
         * own dlo, so it is parked on the parent block and then moved into
         * the element's dlo at (bg_ox, bg_oy) when that exists
         */
        lws_dlo_t                       *bg_dlo;
        lws_fx_t                        bg_ox;
        lws_fx_t                        bg_oy;
 
} lhp_pstack_t;
 
typedef enum lcsp_css_units {
        LCSP_UNIT_NONE,
 
        LCSP_UNIT_NUM,                  /* u.i */
 
        LCSP_UNIT_LENGTH_EM,            /* u.i */
        LCSP_UNIT_LENGTH_EX,            /* u.i */
        LCSP_UNIT_LENGTH_IN,            /* u.i */
        LCSP_UNIT_LENGTH_CM,            /* u.i */
        LCSP_UNIT_LENGTH_MM,            /* u.i */
        LCSP_UNIT_LENGTH_PT,            /* u.i */
        LCSP_UNIT_LENGTH_PC,            /* u.i */
        LCSP_UNIT_LENGTH_PX,            /* u.i */
        LCSP_UNIT_LENGTH_PERCENT,       /* u.i */
        LCSP_UNIT_LENGTH_REM,           /* u.i */
        LCSP_UNIT_LENGTH_VW,            /* u.i, 1vw is 1% of surface width */
        LCSP_UNIT_LENGTH_VH,            /* u.i, 1vh is 1% of surface height */
        LCSP_UNIT_LENGTH_VMIN,          /* u.i, smaller of vw / vh */
        LCSP_UNIT_LENGTH_VMAX,          /* u.i, larger of vw / vh */
 
        LCSP_UNIT_CALC,                 /* u.i is index in string chunk */
 
        LCSP_UNIT_ANGLE_ABS_DEG,        /* u.i */
        LCSP_UNIT_ANGLE_REL_DEG,        /* u.i */
 
        LCSP_UNIT_FREQ_HZ,              /* u.i */
 
        LCSP_UNIT_RGBA,                 /* u.rgba */
 
        LCSP_UNIT_URL,                  /* string at end of atr */
        LCSP_UNIT_STRING,               /* string at end of atr */
        LCSP_UNIT_DATA,                 /* binary data at end of atr */
 
} lcsp_css_units_t;
 
typedef struct lcsp_atr {
        lws_dll2_t              list;
 
        union {
                lws_fx_t        i;
                uint32_t        rgba;   /* for colours */
        } u;
 
        /*
         * A page's cascade is thousands of these: the enums and the length
         * are all small, and stored as int / size_t they cost 8 bytes an
         * attribute that a small target has better uses for
         */
 
        uint16_t                propval; /* lcsp_propvals_t LCSP_PROPVAL_ */
        uint16_t                value_len;      /* for string . url */
 
        uint8_t                 unit;   /* lcsp_css_units_t LCSP_UNIT_ */
        uint8_t                 op;
 
        /* .value_len bytes follow (for strings and blobs) */
} lcsp_atr_t;
 
/* css definitions like font-weight:  */
typedef struct lcsp_defs {
        lws_dll2_t              list;
        lws_dll2_owner_t        atrs;           /* lcsp_atr_t */
        struct lhp_css_var      *var;           /* if prop == LCSP_PROP__COUNT:
                                                 * the --name this declares */
        uint16_t                prop;           /* lcsp_props_t, LCSP_PROP_* */
        uint8_t                 important;      /* declared !important */
} lcsp_defs_t;
 
/*
 * One selector of a stanza's selector list, eg, "div.x > p" from
 * "div.x > p, .y { ... }".  Stored normalized: a single space is the
 * descendant combinator, no spaces around '>', '+', '~' or inside [...].
 */
 
typedef struct lcsp_names {
        lws_dll2_t              list;
        uint32_t                specificity;    /* (layer << 18) | (ids << 12) |
                                                 * (classes << 6) | tags */
        uint16_t                name_len;
        uint16_t                key_ofs;        /* rightmost compound's most
                                                 * selective simple selector,
                                                 * for the cascade prefilter */
        uint16_t                key_len;
        uint8_t                 key_kind;       /* LHP_SELKEY_ */
 
        /* name + NUL follow */
} lcsp_names_t;
 
typedef struct lcsp_stanza { /* css stanza, with names and defs */
        lws_dll2_t              list;
 
        lws_dll2_owner_t        names; /* lcsp_names_t */
        lws_dll2_owner_t        defs; /* lcsp_defs_t */
 
        uint32_t                seq;    /* source order, for cascade ties */
 
        /*
         * Nothing else is written to a stanza after the parse that created
         * it.  Keeping it that way is what lets a stylesheet be immutable,
         * and so live in flash instead of costing heap... the cascade's
         * per-pass "have I taken this one already, and at what specificity"
         * lives on ctx->hits instead
         */
} lcsp_stanza_t;
 
/*
 * The selector index: every selector of every stanza, bucketed by its key
 * (see lhp_sel_key()), so the cascade for an element only visits the
 * selectors whose key it can satisfy plus the keyless ones
 */
 
typedef struct lhp_selidx {
        struct lhp_selidx       *next;
        lcsp_names_t            *nm;
        lcsp_stanza_t           *stz;
} lhp_selidx_t;
 
#define LHP_SELIDX_BUCKETS      64
 
/*
 * A list of stanza references can easily have to bring in the same stanza
 * multiple times, eg, <div><span class=x><div> won't work unless the div
 * stanzas are listed twice at different places in the list.  It means we can't
 * use dll2 directly since the number of references is open-ended.
 *
 * lcsp_stanza_ptr provides indirection that allows multiple listings.
 */
 
typedef struct lcsp_stanza_ptr {
        lws_dll2_t              list;
 
        lcsp_stanza_t           *stz;
} lcsp_stanza_ptr_t;
 
typedef struct lcsp_atr_ptr {
        lws_dll2_t              list;
 
        lcsp_atr_t              *atr;
} lcsp_atr_ptr_t;
 
/*
 * A stanza that matched an element, with the specificity of the best selector
 * that matched.  Each open element keeps a sorted array of these; the last
 * entry has the highest precedence.
 */
 
typedef struct lcsp_match {
        lcsp_stanza_t           *stz;
        uint32_t                specificity;
} lcsp_match_t;
 
typedef struct lhp_css_var {
        lws_dll2_t list;
        size_t name_len;
        lcsp_defs_t *def;
        /* name+NUL follows */
} lhp_css_var_t;
 
/*
 * A cascade layer (@layer): its position in css_layers is its order in the
 * cascade, with the first-declared layer the weakest.  Unlayered rules beat
 * every layer.
 */
 
typedef struct lhp_css_layer {
        lws_dll2_t list;
        size_t len; /* name length, the name may contain NUL bytes */
        /* name+NUL follows (empty for an anonymous layer) */
} lhp_css_layer_t;
 
enum {
        LHP_SELKEY_NONE,
        LHP_SELKEY_TAG,
        LHP_SELKEY_CLASS,
        LHP_SELKEY_ID
};
 
/* layer indexes are 1-based, this is the unlayered ("strongest") value */
#define LHP_CSS_LAYER_NONE      63
 
#define LHP_FLAG_DOCUMENT_END                                   (1 << 0)
 
/*
 * One URL block rule prepared by lws_lhp_set_filter(): a lowercased copy of
 * the rule text, with host_anchor set if it was "||host..." form.  Allocated
 * in ctx->blockac, on ctx->block_rules.
 */
typedef struct lhp_block_rule {
        lws_dll2_t              list;
        size_t                  len;
        uint8_t                 host_anchor:1;
 
        /* lowercased rule text + NUL follows */
} lhp_block_rule_t;
 
typedef struct lhp_ctx {
        lws_dll2_owner_t        stack; /* lhp_pstack_t */
 
        struct lwsac            *cssac; /* css allocations all in an ac */
        struct lwsac            *cascadeac; /* active_stanzas ac */
        struct lwsac            *propatrac; /* prop atr query results ac */
        lws_dll2_owner_t        css; /* lcsp_stanza_t (all in ac) */
 
        lws_dll2_owner_t        *ids;
 
        lws_fx_t                tf;
 
        /*
         * Somewhere for lws_csp_px_base() to compute a resolved length into
         * and hand back a pointer to.  It used to use a slot on the attribute
         * itself, which made every attribute 8 bytes bigger and, worse, made
         * a stylesheet something the layout writes to... callers all consume
         * the result immediately, so a small ring is plenty
         */
        lws_fx_t                fxs[8];
        uint8_t                 fxsi;
        uint8_t                 cb_depth; /* containing blocks being resolved
                                           * for a %, see
                                           * lws_css_compute_cascaded_length() */
 
        lcsp_css_units_t        unit;
        lcsp_stanza_t           *stz; /* current stanza getting properties */
        lcsp_defs_t             *def; /* current property getting values */
 
        lws_dll2_owner_t        active_stanzas; /* lcsp_stanza_ptr_t allocated
                                                 * in cascadeac */
        lws_dll2_owner_t        active_atr; /* lcsp_atr_ptr_t allocated in
                                             * propatrac */
 
        lws_dll2_owner_t        css_vars; /* lhp_css_var_t allocated in cssac */
        lws_dll2_owner_t        css_layers; /* lhp_css_layer_t allocated in
                                             * cascade order */
 
        struct lwsac            *idxac; /* selector index allocations */
        lhp_selidx_t            *selidx[LHP_SELIDX_BUCKETS];
        lhp_selidx_t            *selidx_nokey; /* selectors without a key */
        struct lcsp_match       *hits; /* stanzas hit in the current pass,
                                        * with the best specificity among the
                                        * selectors of theirs that matched */
        uint32_t                hits_alloc;
        uint32_t                hits_count;
        uint32_t                selidx_count; /* stanzas indexed */
        uint32_t                stz_seq;
 
        /* ad / junk filtering, see lws_lhp_set_filter() */
 
        char                    *filter_css; /* strdup of cosmetic filter css */
        lws_dll2_owner_t        block_rules; /* lhp_block_rule_t in blockac */
        struct lwsac            *blockac;
 
        lws_surface_info_t      ic;
 
        const char              *base_url; /* strdup of https://x.com/y.html */
        sul_cb_t                ssevcb; /* callback for ss events */
        lws_sorted_usec_list_t  *ssevsul; /* sul to use to resume rz */
        sul_cb_t                sshtmlevcb; /* callback for more html parse */
        lws_sorted_usec_list_t  *sshtmlevsul; /* sul for more html parse */
 
        void                    *user;
        void                    *user1;
        const char              *tag; /* private */
        size_t                  tag_len; /* private */
 
        int                     npos;
        int                     state; /* private */
        int                     state_css_comm; /* private */
        int                     nl_temp;
        int                     temp_count;
        int                     saved_state;
        int                     entity_start;
 
        uint32_t                flags;
        uint32_t                temp;
        int32_t                 window; /* 0, or ss item flow control limit */
        int32_t                 viewport_h; /* 0, or the css viewport height
                                             * when the surface is taller */
        lws_fx_t                viewport_h_fx;
 
        union {
                uint32_t        s;
                struct {
                        uint32_t        first:1;
                        uint32_t        closing:1;
                        uint32_t        void_element:1;
                        uint32_t        doctype:1;
                        uint32_t        inq:1;
                        uint32_t        tag_used:1;
                        uint32_t        arg:1;
                        uint32_t        default_css:1;
                        uint32_t        style_attr:1; /* nested parse of a style="" value: declarations only */
                        uint32_t        filter_css:1; /* parsing injected filter css */
#define LHP_CSS_PROPVAL_INT_WHOLE       1
#define LHP_CSS_PROPVAL_INT_FRAC        2
#define LHP_CSS_PROPVAL_INT_UNIT        3
                        uint32_t        integer:2;
                        uint32_t        color:2;
                        uint32_t        infunc:1; /* inside name( ... ) value */
                        uint32_t        negval:1; /* '-' seen, number is negative */
                        uint32_t        sq:1; /* attribute value quoted with ' */
                        uint32_t        atr_drop:1; /* current attribute overflowed
                                                * the chunk and is discarded */
                } f;
        } u;
 
        int                     prop; /* lcsp_props_t */
        int                     propval; /* lcsp_propvals_t */
        int16_t                 css_state; /* private */
        int16_t                 cssval_state; /* private */
 
        /*
         * The url of the stylesheet <link> the parse is waiting on, so
         * streams for stylesheets that are not the awaited one cannot
         * complete it early
         */
        char                    await_css_url[240]; /* LHP_URL_LEN */
 
        uint8_t                 in_body:1;
        uint8_t                 finish_css:1;
        uint8_t                 is_css:1;
        uint8_t                 await_css_done:1;
        uint8_t                 await_assets:1; /* doc end deferred for dlo assets */
        uint8_t                 cancelled:1; /* document torn down: assets must
                                             * not resume the parse for it */
 
        uint8_t                 css_block_depth; /* inside applicable @media */
        uint8_t                 css_skip_depth;  /* skipping unusable @-rule */
        uint8_t                 css_layer;       /* 0: unlayered, else the
                                                  * 1-based @layer index */
        uint8_t                 css_layer_depth; /* css_block_depth of the
                                                  * open @layer block */
        uint8_t                 css_lhs_partial:1; /* stanza already created
                                                    * for an overlong selector
                                                    * list */
        uint8_t                 css_lhs_skip:1;  /* selector too long: skip
                                                  * its block */
 
        /* at end so we can memset members above it in one go */
 
        char                    buf[LHP_STRING_CHUNK + 1];
 
} lhp_ctx_t;
 
/*
 * lws_lhp_construct() - Construct an lhp context
 *
 * \param ctx: the lhp context to prepare
 * \param cb: the stream parsing callback
 * \param user: opaque user pointer available from the lhp context
 * \param ic: struct with arguments for lhp context
 *
 * The lhp context is allocated by the caller (the size is known).
 * Prepares an lhp context to parse html.  Returns 0 for OK, or nonzero if OOM.
 */
LWS_VISIBLE LWS_EXTERN int
lws_lhp_construct(lhp_ctx_t *ctx, lhp_callback cb, void *user,
                  const lws_surface_info_t *ic);
 
/*
 * lws_lhp_destruct() - Destroy an lhp context
 *
 * \param ctx: the lhp context to prepare
 *
 * Destroys an lhp context.  The lhp context is allocated by the caller (the
 * size is known).  But there are suballocations that must be destroyed with
 * this.
 */
LWS_VISIBLE LWS_EXTERN void
lws_lhp_destruct(lhp_ctx_t *ctx);

typedef struct lws_lhp_filter {
        const char              *cosmetic_css;
        const char              *block_rules;
} lws_lhp_filter_t;

LWS_VISIBLE LWS_EXTERN int
lws_lhp_set_filter(lhp_ctx_t *ctx, const lws_lhp_filter_t *filter);

LWS_VISIBLE LWS_EXTERN int
lws_lhp_ss_browse(struct lws_context *cx, lws_display_render_state_t *rs,
                  const char *url, sul_cb_t render);

LWS_VISIBLE LWS_EXTERN int
lws_lhp_ss_browse_filter(struct lws_context *cx,
                                 lws_display_render_state_t *rs, const char *url,
                                 sul_cb_t render, const lws_lhp_filter_t *filter);

LWS_VISIBLE LWS_EXTERN void
lws_lhp_ss_cancel(lws_display_render_state_t *rs);

LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t
lws_lhp_parse(lhp_ctx_t *ctx, const uint8_t **buf, size_t *len);

LWS_VISIBLE LWS_EXTERN const lcsp_atr_t *
lws_css_cascade_get_prop_atr(lhp_ctx_t *ctx, lcsp_props_t prop);

LWS_VISIBLE LWS_EXTERN const lcsp_atr_t *
lws_css_get_prop_atr_ps(lhp_ctx_t *ctx, lhp_pstack_t *ps, lcsp_props_t prop);

LWS_VISIBLE LWS_EXTERN int
lws_http_rel_to_url(char *dest, size_t len, const char *base, const char *rel);
 
LWS_VISIBLE LWS_EXTERN lhp_pstack_t *
lws_css_get_parent_block(lhp_ctx_t *ctx, lhp_pstack_t *ps);
 
LWS_VISIBLE LWS_EXTERN const char *
lws_css_pstack_name(lhp_pstack_t *ps);
 
LWS_VISIBLE LWS_EXTERN const char *
lws_html_get_atr(lhp_pstack_t *ps, const char *aname, size_t aname_len);
 
LWS_VISIBLE LWS_EXTERN const lws_fx_t *
lws_csp_px(const lcsp_atr_t *a, lhp_pstack_t *ps);
 
/*
 * The winning declaration's value for one side (idx 0..3 = T R B L) of a
 * shorthand-or-longhand property like border-width / border-color
 */
LWS_VISIBLE LWS_EXTERN const lcsp_atr_t *
lws_css_get_side_atr_ps(lhp_pstack_t *ps, int longhand, int shorthand,
                        int idx, int radii);
 
/*
 * As lws_csp_px(), but lengths in calc() resolve their % terms against base
 * (the containing block content width) when it is non-NULL
 */
LWS_VISIBLE LWS_EXTERN lws_fx_t
lws_csp_calc(const lcsp_atr_t *a, lhp_pstack_t *ps, const lws_fx_t *base,
             int *unitless);
 
LWS_VISIBLE LWS_EXTERN const lws_fx_t *
lws_csp_px_base(const lcsp_atr_t *a, lhp_pstack_t *ps, const lws_fx_t *base);
 
LWS_VISIBLE LWS_EXTERN void
lws_lhp_tag_dlo_id(lhp_ctx_t *ctx, lhp_pstack_t *ps, lws_dlo_t *dlo);
 
void
lhp_set_dlo_padding_margin(lhp_pstack_t *ps, lws_dlo_t *dlo);
 
#define LWS_LHPREF_WIDTH                0
#define LWS_LHPREF_HEIGHT               1
#define LWS_LHPREF_NONE                 2
 
LWS_VISIBLE LWS_EXTERN int
lhp_prop_axis(const lcsp_atr_t *a);
 
LWS_VISIBLE LWS_EXTERN const lcsp_atr_t *
lhp_resolve_var_color(lhp_ctx_t *ctx, const lcsp_atr_t *a);
 
LWS_VISIBLE LWS_EXTERN const lcsp_atr_t *
lhp_resolve_var(lhp_ctx_t *ctx, const lcsp_atr_t *a);