import re
from Tkinter import *
import tkMessageBox

def get(root):
if not hasattr(root, "_searchengine"):
root._searchengine = SearchEngine(root)
# XXX This will never garbage-collect -- who cares
return root._searchengine

class SearchEngine:

def __init__(self, root):
self.root = root
# State shared by search, replace, and grep;
# the search dialogs bind these to UI elements.
self.patvar = StringVar(root) # search pattern
self.revar = BooleanVar(root) # regular expression?
self.casevar = BooleanVar(root) # match case?
self.wordvar = BooleanVar(root) # match whole word?
self.wrapvar = BooleanVar(root) # wrap around buffer?
self.wrapvar.set(1) # (on by default)
self.backvar = BooleanVar(root) # search backwards?

# Access methods

def getpat(self):
return self.patvar.get()

def setpat(self, pat):
self.patvar.set(pat)

def isre(self):
return self.revar.get()

def iscase(self):
return self.casevar.get()

def isword(self):
return self.wordvar.get()

def iswrap(self):
return self.wrapvar.get()

def isback(self):
return self.backvar.get()

# Higher level access methods

def getcookedpat(self):
pat = self.getpat()
if not self.isre():
pat = re.escape(pat)
if self.isword():
pat = r"\b%s\b" % pat
return pat

def getprog(self):
pat = self.getpat()
if not pat:
self.report_error(pat, "Empty regular expression")
return None
pat = self.getcookedpat()
flags = 0
if not self.iscase():
flags = flags | re.IGNORECASE
try:
prog = re.compile(pat, flags)
except re.error, what:
try:
msg, col = what
except:
msg = str(what)
col = -1
self.report_error(pat, msg, col)
return None
return prog

def report_error(self, pat, msg, col=-1):
# Derived class could overrid this with something fancier
msg = "Error: " + str(msg)
if pat:
msg = msg + "\np\Pattern: " + str(pat)
if col >= 0:
msg = msg + "\nOffset: " + str(col)
tkMessageBox.showerror("Regular expression error",
msg, master=self.root)

def setcookedpat(self, pat):
if self.isre():
pat = re.escape(pat)
self.setpat(pat)

def search_text(self, text, prog=None, ok=0):
"""Search a text widget for the pattern.

If prog is given, it should be the precompiled pattern.
Return a tuple (lineno, matchobj); None if not found.

This obeys the wrap and direction (back) settings.

The search starts at the selection (if there is one) or
at the insert mark (otherwise). If the search is forward,
it starts at the right of the selection; for a backward
search, it starts at the left end. An empty match exactly
at either end of the selection (or at the insert mark if
there is no selection) is ignored unless the ok flag is true
-- this is done to guarantee progress.

If the search is allowed to wrap around, it will return the
original selection if (and only if) it is the only match.

"""
if not prog:
prog = self.getprog()
if not prog:
return None # Compilation failed -- stop
wrap = self.wrapvar.get()
first, last = get_selection(text)
if self.isback():
if ok:
start = last
else:
start = first
line, col = get_line_col(start)
res = self.search_backward(text, prog, line, col, wrap, ok)
else:
if ok:
start = first
else:
start = last
line, col = get_line_col(start)
res = self.search_forward(text, prog, line, col, wrap, ok)
return res

def search_forward(self, text, prog, line, col, wrap, ok=0):
wrapped = 0
startline = line
chars = text.get("%d.0" % line, "%d.0" % (line+1))
while chars:
m = prog.search(chars[:-1], col)
if m:
if ok or m.end() > col:
return line, m
line = line + 1
if wrapped and line > startline:
break
col = 0
ok = 1
chars = text.get("%d.0" % line, "%d.0" % (line+1))
if not chars and wrap:
wrapped = 1
wrap = 0
line = 1
chars = text.get("1.0", "2.0")
return None

def search_backward(self, text, prog, line, col, wrap, ok=0):
wrapped = 0
startline = line
chars = text.get("%d.0" % line, "%d.0" % (line+1))
while 1:
m = search_reverse(prog, chars[:-1], col)
if m:
if ok or m.start() < col:
return line, m
line = line - 1
if wrapped and line < startline:
break
ok = 1
if line <= 0:
if not wrap:
break
wrapped = 1
wrap = 0
pos = text.index("end-1c")
line, col = map(int, pos.split("."))
chars = text.get("%d.0" % line, "%d.0" % (line+1))
col = len(chars) - 1
return None

# Helper to search backwards in a string.
# (Optimized for the case where the pattern isn't found.)

def search_reverse(prog, chars, col):
m = prog.search(chars)
if not m:
return None
found = None
i, j = m.span()
while i < col and j <= col:
found = m
if i == j:
j = j+1
m = prog.search(chars, j)
if not m:
break
i, j = m.span()
return found

# Helper to get selection end points, defaulting to insert mark.
# Return a tuple of indices ("line.col" strings).

def get_selection(text):
try:
first = text.index("sel.first")
last = text.index("sel.last")
except TclError:
first = last = None
if not first:
first = text.index("insert")
if not last:
last = first
return first, last

# Helper to parse a text index into a (line, col) tuple.

def get_line_col(index):
line, col = map(int, index.split(".")) # Fails on invalid index
return line, col