varexpand: use list for efficient append

diff --git a/pym/portage/util/__init__.py b/pym/portage/util/__init__.py
index fc4b75b20ddb3be7fa1fe885bd468099a05d0d6e..ae560c0d56311e54f7fc021bf70eb5a5154fede7 100644 (file)
--- a/pym/portage/util/__init__.py
+++ b/pym/portage/util/__init__.py
@@ -661,21 +661,21 @@ def varexpand(mystring, mydict=None):
        insing=0
        indoub=0
        pos=1
-       newstring = ""
+       newstring = []
        while (pos<len(mystring)):
                if (mystring[pos]=="'") and (mystring[pos-1]!="\\"):
                        if (indoub):
-                               newstring=newstring+"'"
+                               newstring.append("'")
                        else:
-                               newstring += "'" # Quote removal is handled by shlex.
+                               newstring.append("'") # Quote removal is handled by shlex.
                                insing=not insing
                        pos=pos+1
                        continue
                elif (mystring[pos]=='"') and (mystring[pos-1]!="\\"):
                        if (insing):
-                               newstring=newstring+'"'
+                               newstring.append('"')
                        else:
-                               newstring += '"' # Quote removal is handled by shlex.
+                               newstring.append('"') # Quote removal is handled by shlex.
                                indoub=not indoub
                        pos=pos+1
                        continue
@@ -683,7 +683,7 @@ def varexpand(mystring, mydict=None):
                        #expansion time
                        if (mystring[pos]=="\n"):
                                #convert newlines to spaces
-                               newstring=newstring+" "
+                               newstring.append(" ")
                                pos=pos+1
                        elif (mystring[pos]=="\\"):
                                # For backslash expansion, this function used to behave like
@@ -695,17 +695,17 @@ def varexpand(mystring, mydict=None):
                                # escaped quotes here, since getconfig() uses shlex
                                # to handle that earlier.
                                if (pos+1>=len(mystring)):
-                                       newstring=newstring+mystring[pos]
+                                       newstring.append(mystring[pos])
                                        break
                                else:
                                        a = mystring[pos + 1]
                                        pos = pos + 2
                                        if a in ("\\", "$"):
-                                               newstring = newstring + a
+                                               newstring.append(a)
                                        elif a == "\n":
                                                pass
                                        else:
-                                               newstring = newstring + mystring[pos-2:pos]
+                                               newstring.append(mystring[pos - 2:pos])
                                        continue
                        elif (mystring[pos]=="$") and (mystring[pos-1]!="\\"):
                                pos=pos+1
@@ -734,15 +734,15 @@ def varexpand(mystring, mydict=None):
                                        return ""
                                numvars=numvars+1
                                if myvarname in mydict:
-                                       newstring=newstring+mydict[myvarname] 
+                                       newstring.append(mydict[myvarname])
                        else:
-                               newstring=newstring+mystring[pos]
+                               newstring.append(mystring[pos])
                                pos=pos+1
                else:
-                       newstring=newstring+mystring[pos]
+                       newstring.append(mystring[pos])
                        pos=pos+1
 
-       return newstring
+       return "".join(newstring)
 
 # broken and removed, but can still be imported
 pickle_write = None