net.html: create html parser module (#6076)

vlib/net/html/dom.v

@@ -0,0 +1,216 @@
+module html
+
+import os
+
+pub struct DocumentObjectModel {
+mut:
+	root           &Tag
+	constructed    bool = false
+	btree          BTree
+	all_tags       []&Tag
+	all_attributes map[string][]&Tag
+	close_tags     map[string]bool // add a counter to see count how many times is closed and parse correctly
+	attributes     map[string][]string
+	tag_attributes map[string][][]&Tag
+	tag_type       map[string][]&Tag
+	debug_file     os.File
+}
+
+[if debug]
+fn (mut dom DocumentObjectModel) print_debug(data string) {
+	$if debug {
+		if data.len > 0 {
+			dom.debug_file.writeln(data)
+		}
+	}
+}
+
+/*
+fn (dom mut DocumentObjectModel) new_root(tag &Tag) {
+	mut new_tag := &Tag{} new_tag.name = "div"
+	new_tag.add_child(dom.root) new_tag.add_child(tag)
+	dom.root = new_tag
+}
+*/
+fn is_close_tag(tag &Tag) bool {
+	if tag.name.len > 0 {
+		return tag.name[0] == 47 // return if equals to /
+	}
+	return false
+}
+
+fn (mut dom DocumentObjectModel) where_is(item_name, attribute_name string) int {
+	if !(attribute_name in dom.attributes) {
+		temp_array := []string{}
+		dom.attributes[attribute_name] = temp_array
+	}
+	mut string_array := dom.attributes[attribute_name]
+	mut counter := 0
+	for value in string_array {
+		if value == item_name {
+			return counter
+		}
+		counter++
+	}
+	string_array << item_name
+	dom.attributes[attribute_name] = string_array
+	return string_array.len - 1
+}
+
+fn (mut dom DocumentObjectModel) add_tag_attribute(tag &Tag) {
+	for attribute_name in tag.attributes.keys() {
+		attribute_value := tag.attributes[attribute_name]
+		location := dom.where_is(attribute_value, attribute_name)
+		if !(attribute_name in dom.tag_attributes) {
+			dom.tag_attributes[attribute_name] = []
+		}
+		for {
+			mut temp_array := dom.tag_attributes[attribute_name]
+			temp_array << []&Tag{}
+			dom.tag_attributes[attribute_name] = temp_array
+			if location < dom.tag_attributes[attribute_name].len + 1 {
+				break
+			}
+		}
+		mut temp_array := dom.tag_attributes[attribute_name][location]
+		temp_array << tag
+		dom.tag_attributes[attribute_name][location] = temp_array
+	}
+}
+
+fn (mut dom DocumentObjectModel) add_tag_by_type(tag &Tag) {
+	tag_name := tag.name
+	if !(tag_name in dom.tag_type) {
+		dom.tag_type[tag_name] = [tag]
+	} else {
+		mut temp_array := dom.tag_type[tag_name]
+		temp_array << tag
+		dom.tag_type[tag_name] = temp_array
+	}
+}
+
+fn (mut dom DocumentObjectModel) add_tag_by_attribute(tag &Tag) {
+	for attribute_name in tag.attributes.keys() {
+		if !(attribute_name in dom.all_attributes) {
+			dom.all_attributes[attribute_name] = [tag]
+		} else {
+			mut temp_array := dom.all_attributes[attribute_name]
+			temp_array << tag
+			dom.all_attributes[attribute_name] = temp_array
+		}
+	}
+}
+
+fn compare_string(a, b string) bool { // for some reason == doesn't work
+	if a.len != b.len {
+		return false
+	}
+	for i := 0; i < a.len; i++ {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+fn (mut dom DocumentObjectModel) construct(tag_list []Tag_ptr) {
+	dom.constructed = true
+	mut temp_map := map[string]int{}
+	mut temp_int := C.INT_MIN
+	mut temp_string := ''
+	mut stack := Stack{}
+	dom.btree = BTree{}
+	dom.root = tag_list[0]
+	dom.all_tags = [tag_list[0]]
+	temp_map['0'] = dom.btree.add_children(tag_list[0])
+	stack.push(0)
+	root_index := 0
+	for index := 1; index < tag_list.len; index++ {
+		mut tag := tag_list[index]
+		dom.print_debug(tag.str())
+		if is_close_tag(tag) {
+			temp_int = stack.peek()
+			temp_string = tag.name[1..tag.name.len] // print(temp_string + " != " + tag_list[temp_int].name + " >> ") // println(temp_string != tag_list[temp_int].name)
+			for !stack.is_null(temp_int) &&
+				!compare_string(temp_string, tag_list[temp_int].name) && !tag_list[temp_int].closed {
+				dom.print_debug(temp_string + ' >> ' + tag_list[temp_int].name + ' ' +
+					compare_string(temp_string, tag_list[temp_int].name).str())
+				stack.pop()
+				temp_int = stack.peek()
+			}
+			temp_int = stack.peek()
+			if !stack.is_null(temp_int) {
+				temp_int = stack.pop()
+			} else {
+				temp_int = root_index
+			}
+			if stack.is_null(temp_int) {
+				stack.push(root_index)
+			}
+			dom.print_debug('Removed ' + temp_string + ' -- ' + tag_list[temp_int].name)
+		} else if tag.name.len > 0 {
+			dom.add_tag_attribute(tag) // error here
+			dom.add_tag_by_attribute(tag)
+			dom.add_tag_by_type(tag)
+			dom.all_tags << tag
+			temp_int = stack.peek()
+			if !stack.is_null(temp_int) {
+				dom.btree.move_pointer(temp_map[temp_int.str()])
+				temp_map[index.str()] = dom.btree.add_children(tag)
+				mut temp_tag := tag_list[temp_int]
+				position_in_parent := temp_tag.add_child(tag) // tag_list[temp_int] = temp_tag
+				tag.add_parent(temp_tag, position_in_parent)
+				/*
+				dom.print_debug("Added ${tag.name} as child of '" + tag_list[temp_int].name +
+					"' which now has ${dom.btree.get_children().len} childrens")
+				*/
+				dom.print_debug("Added $tag.name as child of '" + temp_tag.name +
+					"' which now has $temp_tag.get_children().len childrens")
+			} else { // dom.new_root(tag)
+				stack.push(root_index)
+			}
+			temp_string = '/' + tag.name
+			if temp_string in dom.close_tags && !tag.closed { // if tag ends with />
+				dom.print_debug('Pushed ' + temp_string)
+				stack.push(index)
+			}
+		}
+	} // println(tag_list[root_index]) for debug purposes
+	dom.root = tag_list[0]
+}
+
+pub fn (mut dom DocumentObjectModel) get_by_attribute_value(name, value string) []Tag_ptr {
+	location := dom.where_is(value, name)
+	if dom.tag_attributes[name].len > location {
+		return dom.tag_attributes[name][location]
+	}
+	return []&Tag{}
+}
+
+pub fn (dom DocumentObjectModel) get_by_tag(name string) []Tag_ptr {
+	if name in dom.tag_type {
+		return dom.tag_type[name]
+	}
+	return []&Tag{}
+}
+
+pub fn (dom DocumentObjectModel) get_by_attribute(name string) []Tag_ptr {
+	if name in dom.all_attributes {
+		return dom.all_attributes[name]
+	}
+	return []&Tag{}
+}
+
+pub fn (dom DocumentObjectModel) get_root() &Tag {
+	return dom.root
+}
+
+pub fn (dom DocumentObjectModel) get_all_tags() []Tag_ptr {
+	return dom.all_tags
+}
+
+/*pub fn (dom DocumentObjectModel) get_xpath() XPath {
+	return XPath{
+		dom: dom
+	}
+}*/