Add a fenced code parser in javascript

(imported from commit 42b1dc18ca34cbbdf3cda6e833adde631a9d88f5)

static/js/fenced_code.js

@@ -0,0 +1,157 @@
+var fenced_code = (function () {
+
+var exports = {};
+
+// Parsing routine that can be dropped in to message parsing
+// and formats code blocks
+//
+// This supports arbitrarily nested code blocks as well as
+// auto-completing code blocks missing a trailing close.
+
+// See backend fenced_code.py:71 for associated regexp
+var fencestr = "^(~{3,}|`{3,})"          + // Opening Fence
+               "[ ]*"                    + // Spaces
+               "("                       +
+                   "\\{?\\.?"            +
+                   "([a-zA-Z0-9_+-]*)"   + // Language
+                   "\\}?"                +
+               ")$";
+var fence_re = new RegExp(fencestr);
+
+// Default stashing function does nothing
+var stash_func = function (text) {
+    return text;
+};
+
+function wrap_code(code) {
+    // Trim trailing \n until there's just one left
+    // This mirrors how pygments handles code input
+    code += '\n';
+    while (code.length > 2 && code.substr(code.length - 2) === '\n\n') {
+        code = code.substring(0, code.length - 1);
+    }
+    return '<div class="codehilite"><pre>' + code + '</pre></div>\n';
+}
+
+function wrap_quote(text) {
+    var paragraphs = text.split('\n\n');
+    var quoted_paragraphs = [];
+    // Prefix each quoted paragraph with > at the
+    // beginning of each line
+    _.each(paragraphs, function (paragraph) {
+        var lines = paragraph.split('\n');
+        quoted_paragraphs.push(_.map(
+                                    _.reject(lines, function (line) { return line === ''; }),
+                                    function (line) { return '> ' + line; }).join('\n'));
+    });
+    return quoted_paragraphs.join('\n\n');
+}
+
+exports.set_stash_func = function (stash_handler) {
+    stash_func = stash_handler;
+};
+
+exports.process_fenced_code = function (content) {
+    var input = content.split('\n');
+    var output = [];
+    var handler_stack = [];
+    var consume_line;
+
+    function handler_for_fence(output_lines, fence, lang) {
+        // lang is ignored except for 'quote', as we
+        // don't do syntax highlighting yet
+        return (function () {
+            var lines = [];
+            if (lang === 'quote') {
+                return {
+                    handle_line: function (line) {
+                        if (line === fence) {
+                            this.done();
+                        } else {
+                            consume_line(lines, line);
+                        }
+                    },
+
+                    done: function () {
+                        var text = wrap_quote(lines.join('\n'));
+                        output_lines.push('');
+                        output_lines.push(text);
+                        output_lines.push('');
+                        handler_stack.pop();
+                    }
+                };
+            } else {
+                return {
+                    handle_line: function (line) {
+                        if (line === fence) {
+                            this.done();
+                        } else {
+                            lines.push(line);
+                        }
+                    },
+
+                    done: function () {
+                        var text = wrap_code(lines.join('\n'));
+                        // insert safe HTML that is passed through the parsing
+                        var placeholder = stash_func(text, true);
+                        output_lines.push('');
+                        output_lines.push(placeholder);
+                        output_lines.push('');
+                        handler_stack.pop();
+                    }
+                };
+            }
+        }());
+    }
+
+    function default_hander() {
+        return {
+            handle_line: function (line) {
+                consume_line(output, line);
+            },
+            done: function () {
+                handler_stack.pop();
+            }
+        };
+    }
+
+    consume_line = function consume_line(output_lines, line) {
+        var match = fence_re.exec(line);
+        if (match) {
+            var fence = match[1];
+            var lang = match[3];
+            var handler = handler_for_fence(output_lines, fence, lang);
+            handler_stack.push(handler);
+        } else {
+            output_lines.push(line);
+        }
+    };
+
+    var current_handler = default_hander();
+    handler_stack.push(current_handler);
+
+    _.each(input, function (line) {
+        var handler = handler_stack[handler_stack.length - 1];
+        handler.handle_line(line);
+    });
+
+    // Clean up all trailing blocks by letting them
+    // insert closing fences
+    while (handler_stack.length !== 0) {
+        var handler = handler_stack[handler_stack.length - 1];
+        handler.done();
+    }
+
+    if (output.length > 2 && output[output.length - 2] !== '') {
+        output.push('');
+    }
+
+    return output.join('\n');
+};
+
+return exports;
+
+}());
+if (typeof module !== 'undefined') {
+    module.exports = fenced_code;
+}

tools/jslint/check-all.js

@@ -41,6 +41,9 @@ var globals =
     // alert_words.js
     + ' alert_words'
 
+    // fenced_code.js
+    + ' fenced_code'
+
     // echo.js
     + ' echo'
 

zproject/settings.py

@@ -529,6 +529,7 @@ JS_SPECS = {
             'js/reload.js',
             'js/notifications_bar.js',
             'js/compose_fade.js',
+            'js/fenced_code.js',
             'js/echo.js',
             'js/socket.js',
             'js/compose.js',