HR Util methods
diff --git a/erpnext/hr/utils.py b/erpnext/hr/utils.py
index 057f406..42bfacc 100644
--- a/erpnext/hr/utils.py
+++ b/erpnext/hr/utils.py
@@ -4,8 +4,7 @@
 from __future__ import unicode_literals
 import frappe
 from frappe import _
-from frappe.utils import formatdate, format_datetime
-from frappe.utils import getdate, get_datetime
+from frappe.utils import formatdate, format_datetime, getdate, get_datetime, nowdate
 
 def set_employee_name(doc):
 	if doc.employee and not doc.employee_name:
@@ -49,3 +48,89 @@
 			new_data = get_datetime(new_data)
 		setattr(employee, item.fieldname, new_data)
 	return employee
+
+def validate_dates(doc, from_date, to_date):
+	date_of_joining, relieving_date = frappe.db.get_value("Employee", doc.employee, ["date_of_joining", "relieving_date"])
+	if getdate(from_date) > getdate(to_date):
+		frappe.throw(_("To date can not be less than from date"))
+	elif getdate(from_date) > getdate(nowdate()):
+		frappe.throw(_("Future dates not allowed"))
+	elif date_of_joining and getdate(from_date) < getdate(date_of_joining):
+		frappe.throw(_("From date can not be less than employee's joining date"))
+	elif relieving_date and getdate(to_date) > getdate(relieving_date):
+		frappe.throw(_("To date can not greater than employee's relieving date"))
+
+def validate_overlap(doc, from_date, to_date, company = None):
+	query = """
+		select name
+		from `tab{0}`
+		where name != %(name)s
+		"""
+	query += get_doc_condition(doc.doctype)
+
+	if not doc.name:
+		# hack! if name is null, it could cause problems with !=
+		doc.name = "New "+doc.doctype
+
+	overlap_doc = frappe.db.sql(query.format(doc.doctype),{
+			"employee": doc.employee,
+			"from_date": from_date,
+			"to_date": to_date,
+			"name": doc.name,
+			"company": company
+		}, as_dict = 1)
+
+	if overlap_doc:
+		exists_for = doc.employee
+		if company:
+			exists_for = company
+		throw_overlap_error(doc, exists_for, overlap_doc[0].name, from_date, to_date)
+
+def get_doc_condition(doctype):
+	if doctype == "Compensatory Leave Request":
+		return "and employee = %(employee)s and docstatus < 2 \
+		and (work_from_date between %(from_date)s and %(to_date)s \
+		or work_end_date between %(from_date)s and %(to_date)s \
+		or (work_from_date < %(from_date)s and work_end_date > %(to_date)s))"
+	elif doctype == "Leave Period":
+		return "and company = %(company)s and (from_date between %(from_date)s and %(to_date)s \
+			or to_date between %(from_date)s and %(to_date)s \
+			or (from_date < %(from_date)s and to_date > %(to_date)s))"
+
+def throw_overlap_error(doc, exists_for, overlap_doc, from_date, to_date):
+	msg = _("A {0} exists between {1} and {2} (").format(doc.doctype,
+		formatdate(from_date), formatdate(to_date)) \
+		+ """ <b><a href="#Form/{0}/{1}">{1}</a></b>""".format(doc.doctype, overlap_doc) \
+		+ _(") for {0}").format(exists_for)
+	frappe.throw(msg)
+
+def get_employee_leave_policy(employee):
+	leave_policy = frappe.db.get_value("Employee", employee, "leave_policy")
+	if not leave_policy:
+		employee_grade = frappe.db.get_value("Employee", employee, "grade")
+		if employee_grade:
+			leave_policy = frappe.db.get_value("Employee Grade", employee_grade, "default_leave_policy")
+			if not leave_policy:
+				frappe.throw(_("Employee {0} of grade {1} have no default leave policy").format(employee, employee_grade))
+		else:
+			frappe.throw(_("Employee {0} has no grade to get default leave policy").format(employee))
+	if leave_policy:
+		return frappe.get_doc("Leave Policy", leave_policy)
+
+def get_leave_period(from_date, to_date, company):
+	leave_period = frappe.db.sql("""
+		select name, from_date, to_date
+		from `tabLeave Period`
+		where company=%(company)s and is_active=1
+			and (from_date between %(from_date)s and %(to_date)s
+				or to_date between %(from_date)s and %(to_date)s
+				or (from_date < %(from_date)s and to_date > %(to_date)s))
+	""", {
+		"from_date": from_date,
+		"to_date": to_date,
+		"company": company
+	}, as_dict=1)
+
+	if leave_period:
+		return leave_period
+