streaming api

lib/xml.js

@@ -1,20 +1,102 @@
 var util       = require('./util');
+var Stream      = require('stream').Stream;
 
 var DEFAULT_INDENT = '    ';
 
-function xml (input, indent) {
-    var output = [];
+function xml (input, indent, use_stream) {
+    var stream;
+    var output = "";
+    var interupted = false;
 
     indent = !indent ? '' : indent === true ? DEFAULT_INDENT : indent;
 
+    if (use_stream)
+        stream = new Stream();
+
+    var instant = true,
+        delay = function (func) {
+        if (!instant) {
+            func();
+        } else {
+            process.nextTick(func);
+        }
+    };
+    // disable delay delayed
+    delay(function () { instant = false });
+
+    var append = function (interupt, out) {
+        if (out !== undefined) {
+            output += out;
+        }
+        if (interupt && !interupted) {
+            stream = stream || new Stream();
+            interupted = true;
+        }
+        if (interupt && interupted) {
+            var data = output;
+            delay(function () { stream.emit('data', data) });
+            output = "";
+        }
+    };
+
+    var add = function (value, last) {
+        format(append, resolve(value, indent, indent ? 1 : 0), last);
+    };
+
+    var end = function () {
+        if (stream) {
+            var data = output;
+            delay(function () { stream.emit('data', data) });
+
+            stream.emit('end');
+            stream.readable = false;
+            stream.emit('close');
+        }
+    };
+
     if (input && input.forEach) {
-        input.forEach(function(value){
-            output.push(format(resolve(value, indent, indent ? 1 : 0)));
+        input.forEach(function (value, i) {
+            var last;
+            if (i + 1 == input.length)
+                last = end;
+            add(value, last);
         });
     } else {
-        output.push(format(resolve(input, indent, indent ? 1 : 0)));
+        add(input, end);
+    }
+
+    if (stream) {
+        stream.readable = true;
+        return stream;
     }
-    return output.join(indent ? '\n' : '');
+    return output;
+}
+
+function element (/*input, …*/) {
+    var input = Array.prototype.slice.call(arguments);
+    var self = { _elem:resolve(input) };
+
+    self.push = function (input) {
+        if (!this.append) {
+            throw new Error("not assigned to a parent!");
+        }
+        var that = this;
+        var indent = this._elem.indent;
+        format(this.append, resolve(
+            input, indent, this._elem.icount + (indent ? 1 : 0)),
+            function () { that.append(true) });
+    };
+
+    self.close = function (input) {
+        if (input !== undefined) {
+            this.push(input);
+        }
+        if (this.end) {
+            this.end();
+        }
+    };
+
+    return self;
 }
 
 function create_indent(character, count) {
@@ -26,11 +108,21 @@ function resolve(data, indent, indent_count) {
     var indent_spaces = create_indent(indent, indent_count);
     var name;
     var values = data;
+    var interupt = false;
 
     if (typeof data == 'object') {
         var keys = Object.keys(data);
         name = keys[0];
         values = data[name];
+
+        if (values._elem) {
+            values._elem.name = name;
+            values._elem.icount = indent_count;
+            values._elem.indent = indent;
+            values._elem.indents = indent_spaces;
+            values._elem.interupt = values;
+            return values._elem;
+        }
     }
 
     var attributes = [],
@@ -41,7 +133,6 @@ function resolve(data, indent, indent_count) {
         keys.forEach(function(key){
             attributes.push(attribute(key, obj[key]));
         });
-
     }
 
     switch(typeof values) {
@@ -65,11 +156,13 @@ function resolve(data, indent, indent_count) {
                         if (_name == '_attr') {
                             get_attributes(value._attr);
                         } else {
-                            content.push(resolve(value, indent, indent_count + 1));
+                            content.push(resolve(
+                                value, indent, indent_count + 1));
                         }
                     } else {
                         //string
-                        content.push(create_indent(indent, indent_count + 1) + util.xml_safe(value));
+                        content.push(create_indent(
+                            indent, indent_count + 1) + util.xml_safe(value));
                     }
 
                 });
@@ -84,40 +177,60 @@ function resolve(data, indent, indent_count) {
     }
 
     return { name:  name,
+        interupt:   interupt,
         attributes: attributes,
         content:    content,
+        icount:     indent_count,
         indents:    indent_spaces,
         indent:     indent };
 }
 
-function format(elem) {
-    if (typeof elem != 'object')
-        return elem;
+function format(append, elem, end) {
+    if (typeof elem != 'object') {
+        return append(false, elem);
+    }
 
-    var len = elem.content.length;
-    var output = elem.indents
+    var len = elem.interupt ? 1 : elem.content.length;
+    append(false, elem.indents
         + (elem.name ? '<' + elem.name : '')
         + (elem.attributes.length ? ' ' + elem.attributes.join(' ') : '')
-        + (len ? (elem.name ? '>' : '') : (elem.name ? '/>' : ''));
-
-    if (!len)
-        return output;
-
-    var first = true;
-    while (elem.content.length) {
-        var value = elem.content.shift();
-        if (value === undefined)
-            continue;
-        output += (elem.indent && !first ? '\n' : '') + format(value);
-        first = false;
-    }
-
-    return output + (len > 1 ? elem.indents : '')
-        + (elem.name ? '</' + elem.name + '>' : '');
+        + (len ? (elem.name ? '>' : '') : (elem.name ? '/>' : ''))
+        + (elem.indent && len > 1 ? '\n' : ''));
+
+    if (!len) return append(false, elem.indent ? '\n' : '');
+
+    var interupt, proceed = function () {
+        while (elem.content.length) {
+            var value = elem.content.shift();
+
+            if (value === undefined) continue;
+            if (interupt(value)) return;
+
+            format(append, value);
+        }
+        append(false, (len > 1 ? elem.indents : '')
+            + (elem.name ? '</' + elem.name + '>' : '')
+            + (elem.indent && !end ? '\n' : ''));
+        if (end) end();
+    };
+
+    interupt = function (value) {
+        if (value.interupt) {
+            value.interupt.append = append;
+            value.interupt.end = proceed;
+            value.interupt = false;
+            append(true);
+            return true;
+        }
+        return false;
+    };
+
+    if (!interupt(elem)) proceed();
 }
 
 function attribute(key, value) {
     return key + '=' + '"' + util.xml_safe(value) + '"';
 }
 
+xml.Element = element;
 module.exports = xml;