mirror of
https://gitlab.winehq.org/wine/wine-staging.git
synced 2024-11-21 16:46:54 -08:00
patchutils.py: Implement algorithm to autogenerate #ifdef patches.
This commit is contained in:
Sebastian Lackner
parent
60f7d52725
commit
eadd577d84
304
debian/tools/patchutils.py
vendored
304
debian/tools/patchutils.py
vendored
@ -40,6 +40,14 @@ class PatchApplyError(RuntimeError):
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"""Failed to apply/merge patch."""
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pass
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class PatchDiffError(RuntimeError):
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"""Failed to compute diff."""
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pass
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class CParserError(RuntimeError):
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"""Unable to parse C source."""
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pass
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class PatchObject(object):
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def __init__(self, filename, header):
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self.patch_author = header['author']
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@ -362,3 +370,299 @@ def apply_patch(original, patchfile, reverse=False, fuzz=2):
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except:
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os.unlink(result.name)
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raise
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def generate_ifdef_patch(original, patched, ifdef):
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"""Generate a patch which adds #ifdef where necessary to keep both the original and patched version."""
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def _preprocess_source(fp):
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"""Simple C preprocessor to determine where we can savely add #ifdef instructions."""
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_re_state0 = re.compile("(\"|/[/*])")
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_re_state1 = re.compile("(\\\"|\")")
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_re_state2 = re.compile("\\*/")
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# We need to read the original file, and figure out where lines can be splitted
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lines = []
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original.seek(0)
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for line in original:
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lines.append(line.rstrip("\r\n"))
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split = set([0])
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state = 0
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i = 0
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while i < len(lines):
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# Read a full line (and handle line continuation)
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line = lines[i]
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i += 1
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while line.endswith("\\"):
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if i >= len(lines):
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raise CParserError("Unexpected end of file.")
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line = line[:-1] + lines[i]
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i += 1
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# To find out where we can add our #ifdef tags we use a simple
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# statemachine. This allows finding the beginning of a multiline
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# instruction or comment.
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j = 0
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while True:
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# State 0: No context
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if state == 0:
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match = _re_state0.search(line, j)
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if match is None: break
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if match.group(0) == "\"":
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state = 1 # Begin of string
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elif match.group(0) == "/*":
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state = 2 # Begin of comment
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elif match.group(0) == "//":
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break # Rest of the line is a comment, which can be savely ignored
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else:
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assert 0
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# State 1: Inside of string
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elif state == 1:
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match = _re_state1.search(line, j)
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if match is None:
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raise CParserError("Line ended in the middle of a string.")
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if match.group(0) == "\"":
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state = 0 # End of string
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elif match.group(0) != "\\\"":
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assert 0
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# State 2: Multiline comment
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elif state == 2:
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match = _re_state2.search(line, j)
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if match is None: break
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if match.group(0) == "*/":
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state = 0 # End of comment
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else:
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assert 0
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else:
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raise CParserError("Internal state error.")
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j = match.end()
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# Only in state 0 (no context) we can split here
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if state == 0:
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split.add(i)
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# Ensure that the last comment is properly terminated
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if state != 0:
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raise CParserError("Unexpected end of file.")
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return lines, split
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#
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# The basic of idea of this algorithm is as following:
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#
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# (1) determine diff between original file and patched file
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# (2) run the preprocessor, to determine where #ifdefs can be savely added
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# (3) use diff and preprocessor information to create a merged version containing #ifdefs
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# (4) create another diff to apply the changes on the patched version
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#
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with tempfile.NamedTemporaryFile() as diff:
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exitcode = subprocess.call(["diff", "-u", original.name, patched.name],
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stdout=diff, stderr=_devnull)
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if exitcode == 0:
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return None
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elif exitcode != 1:
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raise PatchDiffError("Failed to compute diff (exitcode %d)." % exitcode)
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# Preprocess the original C source
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lines, split = _preprocess_source(original)
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# Parse the created diff file
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diff.flush()
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diff.seek(0)
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# We expect this output format from 'diff', if this is not the case things might go wrong.
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line = diff.readline()
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assert line.startswith("--- ")
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line = diff.readline()
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assert line.startswith("+++ ")
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hunks = []
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while True:
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line = diff.readline()
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if line == "":
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break
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# Parse each hunk, and extract the srclines and dstlines. This algorithm is very
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# similar to _read_single_patch.
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if not line.startswith("@@ -"):
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raise PatchParserError("Unable to parse line '%s'." % line)
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r = re.match("^@@ -(([0-9]+),)?([0-9]+) \+(([0-9]+),)?([0-9]+) @@", line)
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if not r: raise PatchParserError("Unable to parse hunk header '%s'." % line)
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srcpos = max(int(r.group(2)) - 1, 0) if r.group(2) else 0
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dstpos = max(int(r.group(5)) - 1, 0) if r.group(5) else 0
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srclines, dstlines = int(r.group(3)), int(r.group(6))
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if srclines <= 0 and dstlines <= 0:
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raise PatchParserError("Empty hunk doesn't make sense.")
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srcdata = []
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dstdata = []
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try:
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while srclines > 0 or dstlines > 0:
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line = diff.readline().rstrip("\r\n")
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if line[0] == " ":
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if srclines == 0 or dstlines == 0:
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raise PatchParserError("Corrupted patch.")
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srcdata.append(line[1:])
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dstdata.append(line[1:])
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srclines -= 1
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dstlines -= 1
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elif line[0] == "-":
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if srclines == 0:
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raise PatchParserError("Corrupted patch.")
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srcdata.append(line[1:])
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srclines -= 1
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elif line[0] == "+":
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if dstlines == 0:
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raise PatchParserError("Corrupted patch.")
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dstdata.append(line[1:])
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dstlines -= 1
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elif line[0] == "\\":
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pass # ignore
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else:
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raise PatchParserError("Unexpected line in hunk.")
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except IndexError: # triggered by ""[0]
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raise PatchParserError("Truncated patch.")
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# Ensure that the patch would really apply in practice
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if lines[srcpos:srcpos + len(srcdata)] != srcdata:
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raise PatchParserError("Patch failed to apply.")
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# Strip common lines from the beginning and end
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while len(srcdata) > 0 and len(dstdata) > 0 and \
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srcdata[0] == dstdata[0]:
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srcdata.pop(0)
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dstdata.pop(0)
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srcpos += 1
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dstpos += 1
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while len(srcdata) > 0 and len(dstdata) > 0 and \
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srcdata[-1] == dstdata[-1]:
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srcdata.pop()
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dstdata.pop()
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# Ensure that diff generated valid output
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assert len(srcdata) > 0 or len(dstdata) > 0
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# If this is the first hunk, then check if we have to extend it at the beginning
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if len(hunks) == 0:
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while srcpos > 0 and srcpos not in split:
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srcpos -= 1
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srcdata.insert(0, lines[srcpos])
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dstdata.insert(0, lines[srcpos])
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hunks.append((srcpos, dstpos, srcdata, dstdata))
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# Check if we can merge with the previous hunk
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else:
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prev_srcpos, prev_dstpos, prev_srcdata, prev_dstdata = hunks[-1]
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prev_endpos = prev_srcpos + len(prev_srcdata)
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found = 0
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for i in xrange(prev_endpos, srcpos):
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if i in split:
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found += 1
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# At least two possible splitting positions inbetween
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if found >= 2:
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while prev_endpos not in split:
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prev_srcdata.append(lines[prev_endpos])
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prev_dstdata.append(lines[prev_endpos])
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prev_endpos += 1
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while srcpos not in split:
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srcpos -= 1
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srcdata.insert(0, lines[srcpos])
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dstdata.insert(0, lines[srcpos])
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hunks.append((srcpos, dstpos, srcdata, dstdata))
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# Merge hunks
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else:
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while prev_endpos < srcpos:
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prev_srcdata.append(lines[prev_endpos])
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prev_dstdata.append(lines[prev_endpos])
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prev_endpos += 1
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assert prev_dstpos + len(prev_dstdata) == dstpos
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hunks[-1][2] += srcdata
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hunks[-1][3] += dstdata
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# Ready with this hunk
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pass
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# We might have to extend the last hunk
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if len(hunks):
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prev_srcpos, prev_dstpos, prev_srcdata, prev_dstdata = hunks[-1]
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prev_endpos = prev_srcpos + len(prev_srcdata)
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while prev_endpos < len(lines) and prev_endpos not in split:
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prev_srcdata.append(lines[prev_endpos])
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prev_dstdata.append(lines[prev_endpos])
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prev_endpos += 1
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# We don't need the diff anymore, all hunks are in memory
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diff.close()
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# Generate resulting file with #ifdefs
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with tempfile.NamedTemporaryFile() as intermediate:
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pos = 0
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while len(hunks):
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srcpos, dstpos, srcdata, dstdata = hunks.pop(0)
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if pos < srcpos:
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intermediate.write("\n".join(lines[pos:srcpos]))
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intermediate.write("\n")
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if len(srcdata) and len(dstdata):
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intermediate.write("#if defined(%s)\n" % ifdef)
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intermediate.write("\n".join(dstdata))
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intermediate.write("\n#else /* %s */\n" % ifdef)
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intermediate.write("\n".join(srcdata))
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intermediate.write("\n#endif /* %s */\n" % ifdef)
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elif len(srcdata):
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intermediate.write("#if !defined(%s)\n" % ifdef)
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intermediate.write("\n".join(srcdata))
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intermediate.write("\n#endif /* %s */\n" % ifdef)
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elif len(dstdata):
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intermediate.write("#if defined(%s)\n" % ifdef)
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intermediate.write("\n".join(dstdata))
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intermediate.write("\n#endif /* %s */\n" % ifdef)
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else:
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assert 0
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pos = srcpos + len(srcdata)
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if pos < len(lines):
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intermediate.write("\n".join(lines[pos:]))
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intermediate.write("\n")
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intermediate.flush()
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# Now we can finally compute the diff between the patched file and our intermediate file
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diff = tempfile.NamedTemporaryFile()
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exitcode = subprocess.call(["diff", "-u", patched.name, intermediate.name],
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stdout=diff, stderr=_devnull)
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if exitcode != 1: # exitcode 0 cannot (=shouldn't) happen in this situation
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raise PatchDiffError("Failed to compute diff (exitcode %d)." % exitcode)
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diff.flush()
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diff.seek(0)
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# We expect this output format from 'diff', if this is not the case things might go wrong.
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line = diff.readline()
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assert line.startswith("--- ")
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line = diff.readline()
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assert line.startswith("+++ ")
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# Return the final diff
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return diff
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