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              32
#endif
#if !defined(LHP_MAX_DEPTH)
#define LHP_MAX_DEPTH                   12
#endif
#if !defined(LHP_STRING_CHUNK)
#define LHP_STRING_CHUNK                254
#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,
        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_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,
 
        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_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_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,
 
        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;
 
/*
 * 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; /* currently computed column width */
} lhp_table_col_t;
 
struct lcsp_atr;
 
#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;
 
        /* dynamic cursor inside drt for progressive child placement */
        lws_fx_t                        curx;
        lws_fx_t                        cury;
        lws_fx_t                        widest;
        lws_fx_t                        deepest;
 
        lws_dlo_t                       *dlo_set_curx;
        lws_dlo_t                       *dlo_set_cury;
 
        lws_dll2_owner_t                atr; /* lhp_atr_t */
 
        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_border_radius[4];
 
        const struct lcsp_atr           *css_pos[4];
        const struct lcsp_atr           *css_margin[4];
        const struct lcsp_atr           *css_padding[4];
 
        uint16_t                        tr_idx; /* in table */
        uint16_t                        td_idx; /* in current tr */
 
        uint8_t                         is_block:1; /* children use space in our drt */
        uint8_t                         is_table:1;
 
        /* user layout owns these after initial values set */
 
        lws_dlo_t                       *dlo;
        const lws_display_font_t        *font;
        int                             oi[4];
        int                             positioned[4];
        int                             rel_layout_cursor[4];
        uint8_t                         runon; /* continues same line */
 
} 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_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;
 
        int                     propval; /* lcsp_propvals_t LCSP_PROPVAL_ */
 
        size_t                  value_len;      /* for string . url */
        lcsp_css_units_t        unit;
 
        union {
                lws_fx_t        i;
                uint32_t        rgba;   /* for colours */
        } u;
 
        lws_fx_t                r;
 
        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 */
        lcsp_props_t            prop;           /* lcsp_props_t, LCSP_PROP_* */
} lcsp_defs_t;
 
typedef struct lcsp_names {
        lws_dll2_t              list;
        size_t                  name_len;
 
        /* 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 */
 
} lcsp_stanza_t;
 
/*
 * 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;
 
#define LHP_FLAG_DOCUMENT_END                                   (1 << 0)
 
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;
        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_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;
 
        uint32_t                flags;
        uint32_t                temp;
        int32_t                 window; /* 0, or ss item flow control limit */
 
        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;
#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;
                } f;
        } u;
 
        int                     prop; /* lcsp_props_t */
        int                     propval; /* lcsp_propvals_t */
        int16_t                 css_state; /* private */
        int16_t                 cssval_state; /* private */
 
        uint8_t                 in_body:1;
        uint8_t                 finish_css:1;
        uint8_t                 is_css:1;
        uint8_t                 await_css_done:1;
 
        /* 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);
 
/**
 * lws_lhp_ss_browse() - browse url using SS and parse via lhp to DLOs
 *
 * \param cx: the lws_context
 * \param rs: the user's render state object
 * \param url: the https://x.com/y.xyz URL to browse
 * \param render: the user's linewise render callback (called from \p rs.sul)
 *
 * High level network fetch via SS and render html via lhp / DLO
 *
 * rs->ic must be prepared before calling.
 *
 * Returns nonzero if an early, fatal problem, else returns 0 and  continues
 * asynchronously.
 *
 * If rs->box is (0,0,0,0) on entry, it is set to represent the whole display
 * surface.  Otherwise if not representing the whole display surface, it
 * indicates partial mode should be used.
 */
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_lhp_parse() - parses a chunk of input HTML
 *
 * \p ctx: the parsing context
 * \p buf: pointer to the start of the chunk of html
 * \p len: pointer the number of bytes of html available at *\pbuf
 *
 * Parses up to *len bytes at *buf.  On exit, *buf and *len are adjusted
 * according to how much data was used.  May return before processing all the
 * input.
 *
 * Returns LWS_SRET_WANT_INPUT if the parsing is stalled on some other async
 * event (eg, fetch of image to find out the dimensions).
 *
 * The lws_lhp_ss_browse() api wraps this.
 */
LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t
lws_lhp_parse(lhp_ctx_t *ctx, const uint8_t **buf, size_t *len);
 
/**
 * lws_css_cascade_get_prop_atr() - create active css atr list for property
 *
 * \p ctx: the parsing context
 * \p prop: the LCSP_PROP_ property to generate the attribute list for
 *
 * Returns NULL if no atr or OOM.
 *
 * Otherwise produces a list of active CSS property attributes walkable via
 * ctx->active_atr, and returns the tail one.  For simple attributes where the
 * last definition is the active one, this points to the last definition.
 */
LWS_VISIBLE LWS_EXTERN const lcsp_atr_t *
lws_css_cascade_get_prop_atr(lhp_ctx_t *ctx, lcsp_props_t prop);
 
/**
 * lws_http_rel_to_url() - make absolute url from base and relative
 *
 * \param dest: place to store the result
 * \param len: max length of result including NUL
 * \param base: a reference url including a file part
 * \param rel: the absolute or relative url or path to apply to base
 *
 * Copy the url formof rel into dest, using base to fill in missing context
 *
 * If base is https://x.com/y/z.html
 *
 *   a.html               -> https://x.com/y/a/html
 *   ../b.html            -> https://x.com/b.html
 *   /c.html              -> https://x.com/c.html
 *   https://y.com/a.html -> https://y.com/a.html
 */
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);
 
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);