| 1 | // Package rowrule is the Row Rule as a check on markup. A dropdown |
| 2 | // never sits on a line of its own. It sits in a row beside what it acts |
| 3 | // on. A menu alone on a line reads as a control for nothing in |
| 4 | // particular, and one above a page's title pushes the title down and |
| 5 | // reads as the page's first action. DESIGN.md states the rule. The |
| 6 | // check package holds every gallery example to it; the site's tests |
| 7 | // hold the landing page to it in a browser, at a phone's widths too. |
| 8 | // One check serves both, so the page that sells Fiesta cannot keep a |
| 9 | // looser rule than the gallery teaches. |
| 10 | package rowrule |
| 11 | |
| 12 | import ( |
| 13 | "regexp" |
| 14 | "slices" |
| 15 | "strings" |
| 16 | |
| 17 | xhtml "golang.org/x/net/html" |
| 18 | |
| 19 | "amadan.net/rastrillo/fiesta/internal/markup" |
| 20 | ) |
| 21 | |
| 22 | // Rows are Fiesta's rows a dropdown may sit in, each with why it is a |
| 23 | // row: a dropdown's nearest ancestor that lays something out must carry |
| 24 | // one of these, or be one of the page's own rows that Breaches is given. |
| 25 | var Rows = map[string]string{ |
| 26 | "rst-page-header": "the page header: a title and its actions", |
| 27 | "rst-box-head": "a section head: a heading and its actions", |
| 28 | "rst-lbar": "a list's toolbar", |
| 29 | "rst-bulkbar": "the bulk bar", |
| 30 | "rst-shell-tail": "the shell's bar", |
| 31 | "rst-shell-rail-foot": "the rail's foot", |
| 32 | "rst-page-foot": "the column's footer row", |
| 33 | "rst-dropdown-menu": "a dropdown inside a menu is one of that menu's rows", |
| 34 | } |
| 35 | |
| 36 | // shellChrome is the shell's own chrome. A dropdown there is laid out |
| 37 | // beside the page, not above its title, so it may come before the page |
| 38 | // header in document order; anything else that does is above the title. |
| 39 | var shellChrome = []string{"rst-shell-tail", "rst-shell-rail-foot"} |
| 40 | |
| 41 | // Breaches reads one parsed document and returns one message per |
| 42 | // breach of the Row Rule, in document order. It is a pure function so |
| 43 | // its own test can hold each rule to an exact message. |
| 44 | // |
| 45 | // pageRows names the page's own rows by class, each with why it is a |
| 46 | // row, for a page that lays out its own bars, as the site's landing |
| 47 | // page does. A gallery example passes none: there, a row is a Fiesta |
| 48 | // row. Naming a row here says only where the menu sits; that the row |
| 49 | // keeps the menu on a line with something else is a question of layout, |
| 50 | // which a browser has to answer at each width. |
| 51 | // |
| 52 | // The caller respells the markup with markup.Respell before parsing |
| 53 | // it, so a class-spelled dropdown is visited and a class-spelled row |
| 54 | // counts as its attribute twin; a class list the respeller left alone |
| 55 | // is reported here, so a caller that skips the respell is told. The |
| 56 | // respeller's notes are not read: most are about escaped markup in a |
| 57 | // code sample, which is text and holds no dropdown. |
| 58 | // |
| 59 | // Parsing is the caller's because every caller is a test. x/net's |
| 60 | // html.Parse has a known quadratic case (GO-2026-6860), and govulncheck |
| 61 | // fails the gate for any package of the module that calls it; tests are |
| 62 | // outside its scan, and they parse only this repository's markup. |
| 63 | func Breaches(doc *xhtml.Node, pageRows map[string]string) []string { |
| 64 | var out []string |
| 65 | var order []*xhtml.Node |
| 66 | var walk func(*xhtml.Node) |
| 67 | walk = func(n *xhtml.Node) { |
| 68 | if n.Type == xhtml.ElementNode { |
| 69 | order = append(order, n) |
| 70 | } |
| 71 | for c := n.FirstChild; c != nil; c = c.NextSibling { |
| 72 | walk(c) |
| 73 | } |
| 74 | } |
| 75 | walk(doc) |
| 76 | header := slices.IndexFunc(order, func(n *xhtml.Node) bool { return nodeCarries(n, "rst-page-header") }) |
| 77 | for at, n := range order { |
| 78 | if c, ok := unrespelled(n); ok { |
| 79 | out = append(out, `a class list could not be respelled, so the check cannot read it: <`+n.Data+` class="`+c+`">`) |
| 80 | } |
| 81 | if !isDropdown(n) { |
| 82 | continue |
| 83 | } |
| 84 | row := n.Parent |
| 85 | for row != nil && groupsControls(row) { |
| 86 | row = row.Parent |
| 87 | } |
| 88 | if row == nil || !isRow(row, pageRows) { |
| 89 | out = append(out, "a dropdown sits in "+describe(row)+", not in a row") |
| 90 | } |
| 91 | // Every header and section head around the menu needs its |
| 92 | // heading, not only the nearest row: a toolbar inside a titleless |
| 93 | // page header is still a menu with nothing beside it to act on. |
| 94 | for p := n.Parent; p != nil; p = p.Parent { |
| 95 | if nodeCarries(p, "rst-page-header") && !holds(p, "h1") { |
| 96 | out = append(out, "a page header holds a dropdown and no h1") |
| 97 | } |
| 98 | if nodeCarries(p, "rst-box-head") && !holds(p, "h2", "h3", "h4", "h5", "h6") { |
| 99 | out = append(out, "a section head holds a dropdown and no heading") |
| 100 | } |
| 101 | } |
| 102 | if header >= 0 && at < header && !inShellChrome(n) { |
| 103 | out = append(out, "a dropdown comes before the page header") |
| 104 | } |
| 105 | } |
| 106 | return out |
| 107 | } |
| 108 | |
| 109 | // unrespelled returns the class list of an element the respeller left |
| 110 | // as it was while it still names a component class: a dropdown or a row |
| 111 | // written that way is one this check would never see. Utility classes |
| 112 | // such as rst-sr-only have no attribute twin and stay classes by design. |
| 113 | func unrespelled(n *xhtml.Node) (string, bool) { |
| 114 | for _, a := range n.Attr { |
| 115 | if a.Key != "class" { |
| 116 | continue |
| 117 | } |
| 118 | for _, name := range rstClassName.FindAllString(a.Val, -1) { |
| 119 | if _, _, ok := markup.Attribute(name); ok { |
| 120 | return a.Val, true |
| 121 | } |
| 122 | } |
| 123 | } |
| 124 | return "", false |
| 125 | } |
| 126 | |
| 127 | var rstClassName = regexp.MustCompile(`rst-[A-Za-z0-9_-]+`) |
| 128 | |
| 129 | func isDropdown(n *xhtml.Node) bool { return n.Data == "details" && nodeCarries(n, "rst-dropdown") } |
| 130 | |
| 131 | // nodeCarries reports whether n has the attribute name, whatever its value. |
| 132 | func nodeCarries(n *xhtml.Node, name string) bool { |
| 133 | return slices.ContainsFunc(n.Attr, func(a xhtml.Attribute) bool { return a.Key == name }) |
| 134 | } |
| 135 | |
| 136 | // groupsControls is a <form> or <search> with no rst- attribute: it |
| 137 | // groups a row's controls and lays nothing out, so the row is above it. |
| 138 | // One that carries an rst- attribute is styled, and is what the menu |
| 139 | // sits in. |
| 140 | func groupsControls(n *xhtml.Node) bool { |
| 141 | if n.Type != xhtml.ElementNode || (n.Data != "form" && n.Data != "search") { |
| 142 | return false |
| 143 | } |
| 144 | return !slices.ContainsFunc(n.Attr, func(a xhtml.Attribute) bool { return strings.HasPrefix(a.Key, "rst-") }) |
| 145 | } |
| 146 | |
| 147 | func isRow(n *xhtml.Node, pageRows map[string]string) bool { |
| 148 | return slices.ContainsFunc(n.Attr, func(a xhtml.Attribute) bool { |
| 149 | if _, ok := Rows[a.Key]; ok { |
| 150 | return true |
| 151 | } |
| 152 | if a.Key != "class" { |
| 153 | return false |
| 154 | } |
| 155 | return slices.ContainsFunc(strings.Fields(a.Val), func(c string) bool { _, ok := pageRows[c]; return ok }) |
| 156 | }) |
| 157 | } |
| 158 | |
| 159 | // describe names an element as a failure shows it: its tag and its rst- |
| 160 | // attributes, main[rst-page], so the reader can find it in the markup. |
| 161 | func describe(n *xhtml.Node) string { |
| 162 | if n == nil || n.Type != xhtml.ElementNode { |
| 163 | return "the document" |
| 164 | } |
| 165 | s := n.Data |
| 166 | for _, a := range n.Attr { |
| 167 | if strings.HasPrefix(a.Key, "rst-") { |
| 168 | s += "[" + a.Key + "]" |
| 169 | } |
| 170 | } |
| 171 | return s |
| 172 | } |
| 173 | |
| 174 | // holds reports whether row has one of the tags among its descendants, |
| 175 | // outside any dropdown: a heading inside a menu's panel titles nothing |
| 176 | // in the row, so a header holding only that is still a menu on its own. |
| 177 | func holds(row *xhtml.Node, tags ...string) bool { |
| 178 | for c := row.FirstChild; c != nil; c = c.NextSibling { |
| 179 | if c.Type != xhtml.ElementNode || isDropdown(c) { |
| 180 | continue |
| 181 | } |
| 182 | if slices.Contains(tags, c.Data) || holds(c, tags...) { |
| 183 | return true |
| 184 | } |
| 185 | } |
| 186 | return false |
| 187 | } |
| 188 | |
| 189 | func inShellChrome(n *xhtml.Node) bool { |
| 190 | for p := n.Parent; p != nil; p = p.Parent { |
| 191 | if slices.ContainsFunc(shellChrome, func(name string) bool { return nodeCarries(p, name) }) { |
| 192 | return true |
| 193 | } |
| 194 | } |
| 195 | return false |
| 196 | } |
| 197 | |
amadan