1 # diffhelpers.py - pure Python implementation of diffhelpers.c |
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2 # |
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3 # Copyright 2009 Matt Mackall <mpm@selenic.com> and others |
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4 # |
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5 # This software may be used and distributed according to the terms of the |
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6 # GNU General Public License version 2 or any later version. |
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7 |
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8 from __future__ import absolute_import |
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9 |
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10 def addlines(fp, hunk, lena, lenb, a, b): |
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11 """Read lines from fp into the hunk |
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12 |
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13 The hunk is parsed into two arrays, a and b. a gets the old state of |
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14 the text, b gets the new state. The control char from the hunk is saved |
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15 when inserting into a, but not b (for performance while deleting files.) |
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16 """ |
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17 while True: |
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18 todoa = lena - len(a) |
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19 todob = lenb - len(b) |
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20 num = max(todoa, todob) |
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21 if num == 0: |
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22 break |
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23 for i in xrange(num): |
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24 s = fp.readline() |
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25 if s == "\\ No newline at end of file\n": |
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26 fixnewline(hunk, a, b) |
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27 continue |
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28 if s == "\n": |
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29 # Some patches may be missing the control char |
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30 # on empty lines. Supply a leading space. |
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31 s = " \n" |
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32 hunk.append(s) |
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33 if s.startswith('+'): |
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34 b.append(s[1:]) |
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35 elif s.startswith('-'): |
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36 a.append(s) |
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37 else: |
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38 b.append(s[1:]) |
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39 a.append(s) |
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40 return 0 |
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41 |
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42 def fixnewline(hunk, a, b): |
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43 """Fix up the last lines of a and b when the patch has no newline at EOF""" |
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44 l = hunk[-1] |
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45 # tolerate CRLF in last line |
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46 if l.endswith('\r\n'): |
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47 hline = l[:-2] |
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48 else: |
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49 hline = l[:-1] |
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50 |
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51 if hline.startswith((' ', '+')): |
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52 b[-1] = hline[1:] |
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53 if hline.startswith((' ', '-')): |
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54 a[-1] = hline |
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55 hunk[-1] = hline |
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56 return 0 |
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57 |
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58 def testhunk(a, b, bstart): |
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59 """Compare the lines in a with the lines in b |
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60 |
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61 a is assumed to have a control char at the start of each line, this char |
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62 is ignored in the compare. |
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63 """ |
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64 alen = len(a) |
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65 blen = len(b) |
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66 if alen > blen - bstart: |
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67 return -1 |
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68 for i in xrange(alen): |
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69 if a[i][1:] != b[i + bstart]: |
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70 return -1 |
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71 return 0 |
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