Move global click handlers to per-element ones.

In rustdoc's main.js, we had an onclick handler for the whole document
that would dispatch to handlers for various elements. This change
attaches the handlers to the elements that trigger them, instead.
This simplfies the code and avoids reimplementing the browser's bubbling
functionality.

As part of this change, change from a class to an id for help button.

Move the handlers and associated code for highlighting source lines into
source-script.js (and factor out a shared regex).

Author: jsha

src/librustdoc/html/layout.rs

@@ -105,7 +105,7 @@ crate fn render<T: Print, S: Print>(
                            placeholder=\"Click or press ‘S’ to search, ‘?’ for more options…\" \
                            type=\"search\">\
                 </div>\
-                <button type=\"button\" class=\"help-button\">?</button>
+                <button type=\"button\" id=\"help-button\">?</button>
                 <a id=\"settings-menu\" href=\"{root_path}settings.html\">\
                     <img src=\"{static_root_path}wheel{suffix}.svg\" \
                          width=\"18\" height=\"18\" \

src/librustdoc/html/markdown.rs

@@ -1347,6 +1347,7 @@ fn init_id_map() -> FxHashMap<String, usize> {
     map.insert("theme-picker".to_owned(), 1);
     map.insert("theme-choices".to_owned(), 1);
     map.insert("settings-menu".to_owned(), 1);
+    map.insert("help-button".to_owned(), 1);
     map.insert("main".to_owned(), 1);
     map.insert("search".to_owned(), 1);
     map.insert("crate-search".to_owned(), 1);

src/librustdoc/html/static/main.js

@@ -381,56 +381,9 @@ function hideThemeButtonState() {
         }
     }
 
-    function highlightSourceLines(match, ev) {
-        if (typeof match === "undefined") {
-            // If we're in mobile mode, we should hide the sidebar in any case.
-            hideSidebar();
-            match = window.location.hash.match(/^#?(\d+)(?:-(\d+))?$/);
-        }
-        if (!match) {
-            return;
-        }
-        var from = parseInt(match[1], 10);
-        var to = from;
-        if (typeof match[2] !== "undefined") {
-            to = parseInt(match[2], 10);
-        }
-        if (to < from) {
-            var tmp = to;
-            to = from;
-            from = tmp;
-        }
-        var elem = document.getElementById(from);
-        if (!elem) {
-            return;
-        }
-        if (!ev) {
-            var x = document.getElementById(from);
-            if (x) {
-                x.scrollIntoView();
-            }
-        }
-        onEachLazy(document.getElementsByClassName("line-numbers"), function(e) {
-            onEachLazy(e.getElementsByTagName("span"), function(i_e) {
-                removeClass(i_e, "line-highlighted");
-            });
-        });
-        for (var i = from; i <= to; ++i) {
-            elem = document.getElementById(i);
-            if (!elem) {
-                break;
-            }
-            addClass(elem, "line-highlighted");
-        }
-    }
-
     function onHashChange(ev) {
         // If we're in mobile mode, we should hide the sidebar in any case.
         hideSidebar();
-        var match = window.location.hash.match(/^#?(\d+)(?:-(\d+))?$/);
-        if (match) {
-            return highlightSourceLines(match, ev);
-        }
         handleHashes(ev);
     }
 
@@ -585,78 +538,9 @@ function hideThemeButtonState() {
         }
     }
 
-    function findParentElement(elem, tagName) {
-        do {
-            if (elem && elem.tagName === tagName) {
-                return elem;
-            }
-            elem = elem.parentNode;
-        } while (elem);
-        return null;
-    }
-
     document.addEventListener("keypress", handleShortcut);
     document.addEventListener("keydown", handleShortcut);
 
-    var handleSourceHighlight = (function() {
-        var prev_line_id = 0;
-
-        var set_fragment = function(name) {
-            var x = window.scrollX,
-                y = window.scrollY;
-            if (searchState.browserSupportsHistoryApi()) {
-                history.replaceState(null, null, "#" + name);
-                highlightSourceLines();
-            } else {
-                location.replace("#" + name);
-            }
-            // Prevent jumps when selecting one or many lines
-            window.scrollTo(x, y);
-        };
-
-        return function(ev) {
-            var cur_line_id = parseInt(ev.target.id, 10);
-            ev.preventDefault();
-
-            if (ev.shiftKey && prev_line_id) {
-                // Swap selection if needed
-                if (prev_line_id > cur_line_id) {
-                    var tmp = prev_line_id;
-                    prev_line_id = cur_line_id;
-                    cur_line_id = tmp;
-                }
-
-                set_fragment(prev_line_id + "-" + cur_line_id);
-            } else {
-                prev_line_id = cur_line_id;
-
-                set_fragment(cur_line_id);
-            }
-        };
-    }());
-
-    document.addEventListener("click", function(ev) {
-        var helpElem = getHelpElement(false);
-        if (hasClass(ev.target, "help-button")) {
-            displayHelp(true, ev);
-        } else if (ev.target.tagName === "SPAN" && hasClass(ev.target.parentNode, "line-numbers")) {
-            handleSourceHighlight(ev);
-        } else if (helpElem && hasClass(helpElem, "hidden") === false) {
-            var is_inside_help_popup = ev.target !== helpElem && helpElem.contains(ev.target);
-            if (is_inside_help_popup === false) {
-                addClass(helpElem, "hidden");
-                removeClass(document.body, "blur");
-            }
-        } else {
-            // Making a collapsed element visible on onhashchange seems
-            // too late
-            var a = findParentElement(ev.target, "A");
-            if (a && a.hash) {
-                expandSection(a.hash.replace(/^#/, ""));
-            }
-        }
-    });
-
     (function() {
         var x = document.getElementsByClassName("version-selector");
         if (x.length > 0) {
@@ -1121,6 +1005,27 @@ function hideThemeButtonState() {
         });
     }());
 
+    function handleClick(id, f) {
+        var elem = document.getElementById(id);
+        if (elem) {
+            elem.addEventListener("click", f);
+        }
+    }
+    handleClick("help-button", function(ev) {
+        displayHelp(true, ev);
+    });
+
+    onEachLazy(document.getElementsByTagName("a"), function(el) {
+        // For clicks on internal links (<A> tags with a hash property), we expand the section we're
+        // jumping to *before* jumping there. We can't do this in onHashChange, because it changes
+        // the height of the document so we wind up scrolled to the wrong place.
+        if (el.hash) {
+            el.addEventListener("click", function() {
+                expandSection(el.hash.slice(1));
+            });
+        }
+    });
+
     onEachLazy(document.getElementsByClassName("notable-traits"), function(e) {
         e.onclick = function() {
             this.getElementsByClassName('notable-traits-tooltiptext')[0]
@@ -1165,6 +1070,13 @@ function hideThemeButtonState() {
         addClass(popup, "hidden");
         popup.id = "help";
 
+        popup.addEventListener("click", function(ev) {
+            if (ev.target === popup) {
+                // Clicked the blurred zone outside the help popup; dismiss help.
+                displayHelp(false, ev);
+            }
+        });
+
         var book_info = document.createElement("span");
         book_info.innerHTML = "You can find more information in \
             <a href=\"https://doc.rust-lang.org/rustdoc/\">the rustdoc book</a>.";
@@ -1223,7 +1135,7 @@ function hideThemeButtonState() {
     }
 
     onHashChange(null);
-    window.onhashchange = onHashChange;
+    window.addEventListener("hashchange", onHashChange);
     searchState.setup();
 }());
 

src/librustdoc/html/static/rustdoc.css

@@ -1289,7 +1289,7 @@ h4 > .notable-traits {
 	outline: none;
 }
 
-#settings-menu, .help-button {
+#settings-menu, #help-button {
 	position: absolute;
 	top: 10px;
 }
@@ -1299,7 +1299,7 @@ h4 > .notable-traits {
 	outline: none;
 }
 
-#theme-picker, #settings-menu, .help-button, #copy-path {
+#theme-picker, #settings-menu, #help-button, #copy-path {
 	padding: 4px;
 	width: 27px;
 	height: 29px;
@@ -1308,7 +1308,7 @@ h4 > .notable-traits {
 	cursor: pointer;
 }
 
-.help-button {
+#help-button {
 	right: 30px;
 	font-family: "Fira Sans", Arial, sans-serif;
 	text-align: center;
@@ -1593,7 +1593,7 @@ h4 > .notable-traits {
 	}
 
 	/* We don't display the help button on mobile devices. */
-	.help-button {
+	#help-button {
 		display: none;
 	}
 	.search-container > div {

src/librustdoc/html/static/source-script.js

@@ -3,6 +3,7 @@
 
 // Local js definitions:
 /* global addClass, getCurrentValue, hasClass, removeClass, updateLocalStorage */
+(function() {
 
 function getCurrentFilePath() {
     var parts = window.location.pathname.split("/");
@@ -150,3 +151,99 @@ function createSourceSidebar() {
         selected_elem.focus();
     }
 }
+
+var lineNumbersRegex = /^#?(\d+)(?:-(\d+))?$/;
+
+function highlightSourceLines(match, ev) {
+    if (typeof match === "undefined") {
+        match = window.location.hash.match(lineNumbersRegex);
+    }
+    if (!match) {
+        return;
+    }
+    var from = parseInt(match[1], 10);
+    var to = from;
+    if (typeof match[2] !== "undefined") {
+        to = parseInt(match[2], 10);
+    }
+    if (to < from) {
+        var tmp = to;
+        to = from;
+        from = tmp;
+    }
+    var elem = document.getElementById(from);
+    if (!elem) {
+        return;
+    }
+    if (!ev) {
+        var x = document.getElementById(from);
+        if (x) {
+            x.scrollIntoView();
+        }
+    }
+    onEachLazy(document.getElementsByClassName("line-numbers"), function(e) {
+        onEachLazy(e.getElementsByTagName("span"), function(i_e) {
+            removeClass(i_e, "line-highlighted");
+        });
+    });
+    for (var i = from; i <= to; ++i) {
+        elem = document.getElementById(i);
+        if (!elem) {
+            break;
+        }
+        addClass(elem, "line-highlighted");
+    }
+}
+
+var handleSourceHighlight = (function() {
+    var prev_line_id = 0;
+
+    var set_fragment = function(name) {
+        var x = window.scrollX,
+            y = window.scrollY;
+        if (searchState.browserSupportsHistoryApi()) {
+            history.replaceState(null, null, "#" + name);
+            highlightSourceLines();
+        } else {
+            location.replace("#" + name);
+        }
+        // Prevent jumps when selecting one or many lines
+        window.scrollTo(x, y);
+    };
+
+    return function(ev) {
+        var cur_line_id = parseInt(ev.target.id, 10);
+        ev.preventDefault();
+
+        if (ev.shiftKey && prev_line_id) {
+            // Swap selection if needed
+            if (prev_line_id > cur_line_id) {
+                var tmp = prev_line_id;
+                prev_line_id = cur_line_id;
+                cur_line_id = tmp;
+            }
+
+            set_fragment(prev_line_id + "-" + cur_line_id);
+        } else {
+            prev_line_id = cur_line_id;
+
+            set_fragment(cur_line_id);
+        }
+    };
+}());
+
+window.addEventListener("hashchange", function() {
+    var match = window.location.hash.match(lineNumbersRegex);
+    if (match) {
+        return highlightSourceLines(match, ev);
+    }
+});
+
+onEachLazy(document.getElementsByClassName("line-numbers"), function(el) {
+    el.addEventListener("click", handleSourceHighlight);
+});
+
+highlightSourceLines();
+
+window.createSourceSidebar = createSourceSidebar;
+})();

src/librustdoc/html/static/themes/ayu.css

@@ -503,7 +503,7 @@ kbd {
 	box-shadow-color: #c6cbd1;
 }
 
-#theme-picker, #settings-menu, .help-button, #copy-path {
+#theme-picker, #settings-menu, #help-button, #copy-path {
 	border-color: #5c6773;
 	background-color: #0f1419;
 	color: #fff;
@@ -515,7 +515,7 @@ kbd {
 
 #theme-picker:hover, #theme-picker:focus,
 #settings-menu:hover, #settings-menu:focus,
-.help-button:hover, .help-button:focus,
+#help-button:hover, #help-button:focus,
 #copy-path:hover, #copy-path:focus {
 	border-color: #e0e0e0;
 }

src/librustdoc/html/static/themes/dark.css

@@ -393,15 +393,15 @@ kbd {
 	box-shadow-color: #c6cbd1;
 }
 
-#theme-picker, #settings-menu, .help-button, #copy-path {
+#theme-picker, #settings-menu, #help-button, #copy-path {
 	border-color: #e0e0e0;
 	background: #f0f0f0;
 	color: #000;
 }
 
 #theme-picker:hover, #theme-picker:focus,
 #settings-menu:hover, #settings-menu:focus,
-.help-button:hover, .help-button:focus,
+#help-button:hover, #help-button:focus,
 #copy-path:hover, #copy-path:focus {
 	border-color: #ffb900;
 }