| # Copyright (C) 2014 The Android Open Source Project |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| from __future__ import print_function |
| |
| from collections import deque, OrderedDict |
| from hashlib import sha1 |
| import heapq |
| import itertools |
| import multiprocessing |
| import os |
| import pprint |
| import re |
| import subprocess |
| import sys |
| import threading |
| import tempfile |
| |
| from rangelib import * |
| |
| __all__ = ["EmptyImage", "DataImage", "BlockImageDiff"] |
| |
| def compute_patch(src, tgt, imgdiff=False): |
| srcfd, srcfile = tempfile.mkstemp(prefix="src-") |
| tgtfd, tgtfile = tempfile.mkstemp(prefix="tgt-") |
| patchfd, patchfile = tempfile.mkstemp(prefix="patch-") |
| os.close(patchfd) |
| |
| try: |
| with os.fdopen(srcfd, "wb") as f_src: |
| for p in src: |
| f_src.write(p) |
| |
| with os.fdopen(tgtfd, "wb") as f_tgt: |
| for p in tgt: |
| f_tgt.write(p) |
| try: |
| os.unlink(patchfile) |
| except OSError: |
| pass |
| if imgdiff: |
| p = subprocess.call(["imgdiff", "-z", srcfile, tgtfile, patchfile], |
| stdout=open("/dev/null", "a"), |
| stderr=subprocess.STDOUT) |
| else: |
| p = subprocess.call(["bsdiff", srcfile, tgtfile, patchfile]) |
| |
| if p: |
| raise ValueError("diff failed: " + str(p)) |
| |
| with open(patchfile, "rb") as f: |
| return f.read() |
| finally: |
| try: |
| os.unlink(srcfile) |
| os.unlink(tgtfile) |
| os.unlink(patchfile) |
| except OSError: |
| pass |
| |
| class EmptyImage(object): |
| """A zero-length image.""" |
| blocksize = 4096 |
| care_map = RangeSet() |
| total_blocks = 0 |
| file_map = {} |
| def ReadRangeSet(self, ranges): |
| return () |
| def TotalSha1(self): |
| return sha1().hexdigest() |
| |
| |
| class DataImage(object): |
| """An image wrapped around a single string of data.""" |
| |
| def __init__(self, data, trim=False, pad=False): |
| self.data = data |
| self.blocksize = 4096 |
| |
| assert not (trim and pad) |
| |
| partial = len(self.data) % self.blocksize |
| if partial > 0: |
| if trim: |
| self.data = self.data[:-partial] |
| elif pad: |
| self.data += '\0' * (self.blocksize - partial) |
| else: |
| raise ValueError(("data for DataImage must be multiple of %d bytes " |
| "unless trim or pad is specified") % |
| (self.blocksize,)) |
| |
| assert len(self.data) % self.blocksize == 0 |
| |
| self.total_blocks = len(self.data) / self.blocksize |
| self.care_map = RangeSet(data=(0, self.total_blocks)) |
| |
| zero_blocks = [] |
| nonzero_blocks = [] |
| reference = '\0' * self.blocksize |
| |
| for i in range(self.total_blocks): |
| d = self.data[i*self.blocksize : (i+1)*self.blocksize] |
| if d == reference: |
| zero_blocks.append(i) |
| zero_blocks.append(i+1) |
| else: |
| nonzero_blocks.append(i) |
| nonzero_blocks.append(i+1) |
| |
| self.file_map = {"__ZERO": RangeSet(zero_blocks), |
| "__NONZERO": RangeSet(nonzero_blocks)} |
| |
| def ReadRangeSet(self, ranges): |
| return [self.data[s*self.blocksize:e*self.blocksize] for (s, e) in ranges] |
| |
| def TotalSha1(self): |
| if not hasattr(self, "sha1"): |
| self.sha1 = sha1(self.data).hexdigest() |
| return self.sha1 |
| |
| |
| class Transfer(object): |
| def __init__(self, tgt_name, src_name, tgt_ranges, src_ranges, style, by_id): |
| self.tgt_name = tgt_name |
| self.src_name = src_name |
| self.tgt_ranges = tgt_ranges |
| self.src_ranges = src_ranges |
| self.style = style |
| self.intact = (getattr(tgt_ranges, "monotonic", False) and |
| getattr(src_ranges, "monotonic", False)) |
| self.goes_before = {} |
| self.goes_after = {} |
| |
| self.stash_before = [] |
| self.use_stash = [] |
| |
| self.id = len(by_id) |
| by_id.append(self) |
| |
| def NetStashChange(self): |
| return (sum(sr.size() for (_, sr) in self.stash_before) - |
| sum(sr.size() for (_, sr) in self.use_stash)) |
| |
| def __str__(self): |
| return (str(self.id) + ": <" + str(self.src_ranges) + " " + self.style + |
| " to " + str(self.tgt_ranges) + ">") |
| |
| |
| # BlockImageDiff works on two image objects. An image object is |
| # anything that provides the following attributes: |
| # |
| # blocksize: the size in bytes of a block, currently must be 4096. |
| # |
| # total_blocks: the total size of the partition/image, in blocks. |
| # |
| # care_map: a RangeSet containing which blocks (in the range [0, |
| # total_blocks) we actually care about; i.e. which blocks contain |
| # data. |
| # |
| # file_map: a dict that partitions the blocks contained in care_map |
| # into smaller domains that are useful for doing diffs on. |
| # (Typically a domain is a file, and the key in file_map is the |
| # pathname.) |
| # |
| # ReadRangeSet(): a function that takes a RangeSet and returns the |
| # data contained in the image blocks of that RangeSet. The data |
| # is returned as a list or tuple of strings; concatenating the |
| # elements together should produce the requested data. |
| # Implementations are free to break up the data into list/tuple |
| # elements in any way that is convenient. |
| # |
| # TotalSha1(): a function that returns (as a hex string) the SHA-1 |
| # hash of all the data in the image (ie, all the blocks in the |
| # care_map) |
| # |
| # When creating a BlockImageDiff, the src image may be None, in which |
| # case the list of transfers produced will never read from the |
| # original image. |
| |
| class BlockImageDiff(object): |
| def __init__(self, tgt, src=None, threads=None, version=2): |
| if threads is None: |
| threads = multiprocessing.cpu_count() // 2 |
| if threads == 0: threads = 1 |
| self.threads = threads |
| self.version = version |
| |
| assert version in (1, 2) |
| |
| self.tgt = tgt |
| if src is None: |
| src = EmptyImage() |
| self.src = src |
| |
| # The updater code that installs the patch always uses 4k blocks. |
| assert tgt.blocksize == 4096 |
| assert src.blocksize == 4096 |
| |
| # The range sets in each filemap should comprise a partition of |
| # the care map. |
| self.AssertPartition(src.care_map, src.file_map.values()) |
| self.AssertPartition(tgt.care_map, tgt.file_map.values()) |
| |
| def Compute(self, prefix): |
| # When looking for a source file to use as the diff input for a |
| # target file, we try: |
| # 1) an exact path match if available, otherwise |
| # 2) a exact basename match if available, otherwise |
| # 3) a basename match after all runs of digits are replaced by |
| # "#" if available, otherwise |
| # 4) we have no source for this target. |
| self.AbbreviateSourceNames() |
| self.FindTransfers() |
| |
| # Find the ordering dependencies among transfers (this is O(n^2) |
| # in the number of transfers). |
| self.GenerateDigraph() |
| # Find a sequence of transfers that satisfies as many ordering |
| # dependencies as possible (heuristically). |
| self.FindVertexSequence() |
| # Fix up the ordering dependencies that the sequence didn't |
| # satisfy. |
| if self.version == 1: |
| self.RemoveBackwardEdges() |
| else: |
| self.ReverseBackwardEdges() |
| self.ImproveVertexSequence() |
| |
| # Double-check our work. |
| self.AssertSequenceGood() |
| |
| self.ComputePatches(prefix) |
| self.WriteTransfers(prefix) |
| |
| def WriteTransfers(self, prefix): |
| out = [] |
| |
| out.append("%d\n" % (self.version,)) # format version number |
| total = 0 |
| performs_read = False |
| |
| stashes = {} |
| stashed_blocks = 0 |
| max_stashed_blocks = 0 |
| |
| free_stash_ids = [] |
| next_stash_id = 0 |
| |
| for xf in self.transfers: |
| |
| if self.version < 2: |
| assert not xf.stash_before |
| assert not xf.use_stash |
| |
| for s, sr in xf.stash_before: |
| assert s not in stashes |
| if free_stash_ids: |
| sid = heapq.heappop(free_stash_ids) |
| else: |
| sid = next_stash_id |
| next_stash_id += 1 |
| stashes[s] = sid |
| stashed_blocks += sr.size() |
| out.append("stash %d %s\n" % (sid, sr.to_string_raw())) |
| |
| if stashed_blocks > max_stashed_blocks: |
| max_stashed_blocks = stashed_blocks |
| |
| if self.version == 1: |
| src_string = xf.src_ranges.to_string_raw() |
| elif self.version == 2: |
| |
| # <# blocks> <src ranges> |
| # OR |
| # <# blocks> <src ranges> <src locs> <stash refs...> |
| # OR |
| # <# blocks> - <stash refs...> |
| |
| size = xf.src_ranges.size() |
| src_string = [str(size)] |
| |
| unstashed_src_ranges = xf.src_ranges |
| mapped_stashes = [] |
| for s, sr in xf.use_stash: |
| sid = stashes.pop(s) |
| stashed_blocks -= sr.size() |
| unstashed_src_ranges = unstashed_src_ranges.subtract(sr) |
| sr = xf.src_ranges.map_within(sr) |
| mapped_stashes.append(sr) |
| src_string.append("%d:%s" % (sid, sr.to_string_raw())) |
| heapq.heappush(free_stash_ids, sid) |
| |
| if unstashed_src_ranges: |
| src_string.insert(1, unstashed_src_ranges.to_string_raw()) |
| if xf.use_stash: |
| mapped_unstashed = xf.src_ranges.map_within(unstashed_src_ranges) |
| src_string.insert(2, mapped_unstashed.to_string_raw()) |
| mapped_stashes.append(mapped_unstashed) |
| self.AssertPartition(RangeSet(data=(0, size)), mapped_stashes) |
| else: |
| src_string.insert(1, "-") |
| self.AssertPartition(RangeSet(data=(0, size)), mapped_stashes) |
| |
| src_string = " ".join(src_string) |
| |
| # both versions: |
| # zero <rangeset> |
| # new <rangeset> |
| # erase <rangeset> |
| # |
| # version 1: |
| # bsdiff patchstart patchlen <src rangeset> <tgt rangeset> |
| # imgdiff patchstart patchlen <src rangeset> <tgt rangeset> |
| # move <src rangeset> <tgt rangeset> |
| # |
| # version 2: |
| # bsdiff patchstart patchlen <tgt rangeset> <src_string> |
| # imgdiff patchstart patchlen <tgt rangeset> <src_string> |
| # move <tgt rangeset> <src_string> |
| |
| tgt_size = xf.tgt_ranges.size() |
| |
| if xf.style == "new": |
| assert xf.tgt_ranges |
| out.append("%s %s\n" % (xf.style, xf.tgt_ranges.to_string_raw())) |
| total += tgt_size |
| elif xf.style == "move": |
| performs_read = True |
| assert xf.tgt_ranges |
| assert xf.src_ranges.size() == tgt_size |
| if xf.src_ranges != xf.tgt_ranges: |
| if self.version == 1: |
| out.append("%s %s %s\n" % ( |
| xf.style, |
| xf.src_ranges.to_string_raw(), xf.tgt_ranges.to_string_raw())) |
| elif self.version == 2: |
| out.append("%s %s %s\n" % ( |
| xf.style, |
| xf.tgt_ranges.to_string_raw(), src_string)) |
| total += tgt_size |
| elif xf.style in ("bsdiff", "imgdiff"): |
| performs_read = True |
| assert xf.tgt_ranges |
| assert xf.src_ranges |
| if self.version == 1: |
| out.append("%s %d %d %s %s\n" % ( |
| xf.style, xf.patch_start, xf.patch_len, |
| xf.src_ranges.to_string_raw(), xf.tgt_ranges.to_string_raw())) |
| elif self.version == 2: |
| out.append("%s %d %d %s %s\n" % ( |
| xf.style, xf.patch_start, xf.patch_len, |
| xf.tgt_ranges.to_string_raw(), src_string)) |
| total += tgt_size |
| elif xf.style == "zero": |
| assert xf.tgt_ranges |
| to_zero = xf.tgt_ranges.subtract(xf.src_ranges) |
| if to_zero: |
| out.append("%s %s\n" % (xf.style, to_zero.to_string_raw())) |
| total += to_zero.size() |
| else: |
| raise ValueError, "unknown transfer style '%s'\n" % (xf.style,) |
| |
| out.insert(1, str(total) + "\n") |
| if self.version >= 2: |
| # version 2 only: after the total block count, we give the number |
| # of stash slots needed, and the maximum size needed (in blocks) |
| out.insert(2, str(next_stash_id) + "\n") |
| out.insert(3, str(max_stashed_blocks) + "\n") |
| |
| # sanity check: abort if we're going to need more than 512 MB if |
| # stash space |
| assert max_stashed_blocks * self.tgt.blocksize < (512 << 20) |
| |
| all_tgt = RangeSet(data=(0, self.tgt.total_blocks)) |
| if performs_read: |
| # if some of the original data is used, then at the end we'll |
| # erase all the blocks on the partition that don't contain data |
| # in the new image. |
| new_dontcare = all_tgt.subtract(self.tgt.care_map) |
| if new_dontcare: |
| out.append("erase %s\n" % (new_dontcare.to_string_raw(),)) |
| else: |
| # if nothing is read (ie, this is a full OTA), then we can start |
| # by erasing the entire partition. |
| out.insert(2, "erase %s\n" % (all_tgt.to_string_raw(),)) |
| |
| with open(prefix + ".transfer.list", "wb") as f: |
| for i in out: |
| f.write(i) |
| |
| if self.version >= 2: |
| print("max stashed blocks: %d (%d bytes)\n" % ( |
| max_stashed_blocks, max_stashed_blocks * self.tgt.blocksize)) |
| |
| def ComputePatches(self, prefix): |
| print("Reticulating splines...") |
| diff_q = [] |
| patch_num = 0 |
| with open(prefix + ".new.dat", "wb") as new_f: |
| for xf in self.transfers: |
| if xf.style == "zero": |
| pass |
| elif xf.style == "new": |
| for piece in self.tgt.ReadRangeSet(xf.tgt_ranges): |
| new_f.write(piece) |
| elif xf.style == "diff": |
| src = self.src.ReadRangeSet(xf.src_ranges) |
| tgt = self.tgt.ReadRangeSet(xf.tgt_ranges) |
| |
| # We can't compare src and tgt directly because they may have |
| # the same content but be broken up into blocks differently, eg: |
| # |
| # ["he", "llo"] vs ["h", "ello"] |
| # |
| # We want those to compare equal, ideally without having to |
| # actually concatenate the strings (these may be tens of |
| # megabytes). |
| |
| src_sha1 = sha1() |
| for p in src: |
| src_sha1.update(p) |
| tgt_sha1 = sha1() |
| tgt_size = 0 |
| for p in tgt: |
| tgt_sha1.update(p) |
| tgt_size += len(p) |
| |
| if src_sha1.digest() == tgt_sha1.digest(): |
| # These are identical; we don't need to generate a patch, |
| # just issue copy commands on the device. |
| xf.style = "move" |
| else: |
| # For files in zip format (eg, APKs, JARs, etc.) we would |
| # like to use imgdiff -z if possible (because it usually |
| # produces significantly smaller patches than bsdiff). |
| # This is permissible if: |
| # |
| # - the source and target files are monotonic (ie, the |
| # data is stored with blocks in increasing order), and |
| # - we haven't removed any blocks from the source set. |
| # |
| # If these conditions are satisfied then appending all the |
| # blocks in the set together in order will produce a valid |
| # zip file (plus possibly extra zeros in the last block), |
| # which is what imgdiff needs to operate. (imgdiff is |
| # fine with extra zeros at the end of the file.) |
| imgdiff = (xf.intact and |
| xf.tgt_name.split(".")[-1].lower() |
| in ("apk", "jar", "zip")) |
| xf.style = "imgdiff" if imgdiff else "bsdiff" |
| diff_q.append((tgt_size, src, tgt, xf, patch_num)) |
| patch_num += 1 |
| |
| else: |
| assert False, "unknown style " + xf.style |
| |
| if diff_q: |
| if self.threads > 1: |
| print("Computing patches (using %d threads)..." % (self.threads,)) |
| else: |
| print("Computing patches...") |
| diff_q.sort() |
| |
| patches = [None] * patch_num |
| |
| lock = threading.Lock() |
| def diff_worker(): |
| while True: |
| with lock: |
| if not diff_q: return |
| tgt_size, src, tgt, xf, patchnum = diff_q.pop() |
| patch = compute_patch(src, tgt, imgdiff=(xf.style == "imgdiff")) |
| size = len(patch) |
| with lock: |
| patches[patchnum] = (patch, xf) |
| print("%10d %10d (%6.2f%%) %7s %s" % ( |
| size, tgt_size, size * 100.0 / tgt_size, xf.style, |
| xf.tgt_name if xf.tgt_name == xf.src_name else ( |
| xf.tgt_name + " (from " + xf.src_name + ")"))) |
| |
| threads = [threading.Thread(target=diff_worker) |
| for i in range(self.threads)] |
| for th in threads: |
| th.start() |
| while threads: |
| threads.pop().join() |
| else: |
| patches = [] |
| |
| p = 0 |
| with open(prefix + ".patch.dat", "wb") as patch_f: |
| for patch, xf in patches: |
| xf.patch_start = p |
| xf.patch_len = len(patch) |
| patch_f.write(patch) |
| p += len(patch) |
| |
| def AssertSequenceGood(self): |
| # Simulate the sequences of transfers we will output, and check that: |
| # - we never read a block after writing it, and |
| # - we write every block we care about exactly once. |
| |
| # Start with no blocks having been touched yet. |
| touched = RangeSet() |
| |
| # Imagine processing the transfers in order. |
| for xf in self.transfers: |
| # Check that the input blocks for this transfer haven't yet been touched. |
| |
| x = xf.src_ranges |
| if self.version >= 2: |
| for _, sr in xf.use_stash: |
| x = x.subtract(sr) |
| |
| assert not touched.overlaps(x) |
| # Check that the output blocks for this transfer haven't yet been touched. |
| assert not touched.overlaps(xf.tgt_ranges) |
| # Touch all the blocks written by this transfer. |
| touched = touched.union(xf.tgt_ranges) |
| |
| # Check that we've written every target block. |
| assert touched == self.tgt.care_map |
| |
| def ImproveVertexSequence(self): |
| print("Improving vertex order...") |
| |
| # At this point our digraph is acyclic; we reversed any edges that |
| # were backwards in the heuristically-generated sequence. The |
| # previously-generated order is still acceptable, but we hope to |
| # find a better order that needs less memory for stashed data. |
| # Now we do a topological sort to generate a new vertex order, |
| # using a greedy algorithm to choose which vertex goes next |
| # whenever we have a choice. |
| |
| # Make a copy of the edge set; this copy will get destroyed by the |
| # algorithm. |
| for xf in self.transfers: |
| xf.incoming = xf.goes_after.copy() |
| xf.outgoing = xf.goes_before.copy() |
| |
| L = [] # the new vertex order |
| |
| # S is the set of sources in the remaining graph; we always choose |
| # the one that leaves the least amount of stashed data after it's |
| # executed. |
| S = [(u.NetStashChange(), u.order, u) for u in self.transfers |
| if not u.incoming] |
| heapq.heapify(S) |
| |
| while S: |
| _, _, xf = heapq.heappop(S) |
| L.append(xf) |
| for u in xf.outgoing: |
| del u.incoming[xf] |
| if not u.incoming: |
| heapq.heappush(S, (u.NetStashChange(), u.order, u)) |
| |
| # if this fails then our graph had a cycle. |
| assert len(L) == len(self.transfers) |
| |
| self.transfers = L |
| for i, xf in enumerate(L): |
| xf.order = i |
| |
| def RemoveBackwardEdges(self): |
| print("Removing backward edges...") |
| in_order = 0 |
| out_of_order = 0 |
| lost_source = 0 |
| |
| for xf in self.transfers: |
| lost = 0 |
| size = xf.src_ranges.size() |
| for u in xf.goes_before: |
| # xf should go before u |
| if xf.order < u.order: |
| # it does, hurray! |
| in_order += 1 |
| else: |
| # it doesn't, boo. trim the blocks that u writes from xf's |
| # source, so that xf can go after u. |
| out_of_order += 1 |
| assert xf.src_ranges.overlaps(u.tgt_ranges) |
| xf.src_ranges = xf.src_ranges.subtract(u.tgt_ranges) |
| xf.intact = False |
| |
| if xf.style == "diff" and not xf.src_ranges: |
| # nothing left to diff from; treat as new data |
| xf.style = "new" |
| |
| lost = size - xf.src_ranges.size() |
| lost_source += lost |
| |
| print((" %d/%d dependencies (%.2f%%) were violated; " |
| "%d source blocks removed.") % |
| (out_of_order, in_order + out_of_order, |
| (out_of_order * 100.0 / (in_order + out_of_order)) |
| if (in_order + out_of_order) else 0.0, |
| lost_source)) |
| |
| def ReverseBackwardEdges(self): |
| print("Reversing backward edges...") |
| in_order = 0 |
| out_of_order = 0 |
| stashes = 0 |
| stash_size = 0 |
| |
| for xf in self.transfers: |
| lost = 0 |
| size = xf.src_ranges.size() |
| for u in xf.goes_before.copy(): |
| # xf should go before u |
| if xf.order < u.order: |
| # it does, hurray! |
| in_order += 1 |
| else: |
| # it doesn't, boo. modify u to stash the blocks that it |
| # writes that xf wants to read, and then require u to go |
| # before xf. |
| out_of_order += 1 |
| |
| overlap = xf.src_ranges.intersect(u.tgt_ranges) |
| assert overlap |
| |
| u.stash_before.append((stashes, overlap)) |
| xf.use_stash.append((stashes, overlap)) |
| stashes += 1 |
| stash_size += overlap.size() |
| |
| # reverse the edge direction; now xf must go after u |
| del xf.goes_before[u] |
| del u.goes_after[xf] |
| xf.goes_after[u] = None # value doesn't matter |
| u.goes_before[xf] = None |
| |
| print((" %d/%d dependencies (%.2f%%) were violated; " |
| "%d source blocks stashed.") % |
| (out_of_order, in_order + out_of_order, |
| (out_of_order * 100.0 / (in_order + out_of_order)) |
| if (in_order + out_of_order) else 0.0, |
| stash_size)) |
| |
| def FindVertexSequence(self): |
| print("Finding vertex sequence...") |
| |
| # This is based on "A Fast & Effective Heuristic for the Feedback |
| # Arc Set Problem" by P. Eades, X. Lin, and W.F. Smyth. Think of |
| # it as starting with the digraph G and moving all the vertices to |
| # be on a horizontal line in some order, trying to minimize the |
| # number of edges that end up pointing to the left. Left-pointing |
| # edges will get removed to turn the digraph into a DAG. In this |
| # case each edge has a weight which is the number of source blocks |
| # we'll lose if that edge is removed; we try to minimize the total |
| # weight rather than just the number of edges. |
| |
| # Make a copy of the edge set; this copy will get destroyed by the |
| # algorithm. |
| for xf in self.transfers: |
| xf.incoming = xf.goes_after.copy() |
| xf.outgoing = xf.goes_before.copy() |
| |
| # We use an OrderedDict instead of just a set so that the output |
| # is repeatable; otherwise it would depend on the hash values of |
| # the transfer objects. |
| G = OrderedDict() |
| for xf in self.transfers: |
| G[xf] = None |
| s1 = deque() # the left side of the sequence, built from left to right |
| s2 = deque() # the right side of the sequence, built from right to left |
| |
| while G: |
| |
| # Put all sinks at the end of the sequence. |
| while True: |
| sinks = [u for u in G if not u.outgoing] |
| if not sinks: break |
| for u in sinks: |
| s2.appendleft(u) |
| del G[u] |
| for iu in u.incoming: |
| del iu.outgoing[u] |
| |
| # Put all the sources at the beginning of the sequence. |
| while True: |
| sources = [u for u in G if not u.incoming] |
| if not sources: break |
| for u in sources: |
| s1.append(u) |
| del G[u] |
| for iu in u.outgoing: |
| del iu.incoming[u] |
| |
| if not G: break |
| |
| # Find the "best" vertex to put next. "Best" is the one that |
| # maximizes the net difference in source blocks saved we get by |
| # pretending it's a source rather than a sink. |
| |
| max_d = None |
| best_u = None |
| for u in G: |
| d = sum(u.outgoing.values()) - sum(u.incoming.values()) |
| if best_u is None or d > max_d: |
| max_d = d |
| best_u = u |
| |
| u = best_u |
| s1.append(u) |
| del G[u] |
| for iu in u.outgoing: |
| del iu.incoming[u] |
| for iu in u.incoming: |
| del iu.outgoing[u] |
| |
| # Now record the sequence in the 'order' field of each transfer, |
| # and by rearranging self.transfers to be in the chosen sequence. |
| |
| new_transfers = [] |
| for x in itertools.chain(s1, s2): |
| x.order = len(new_transfers) |
| new_transfers.append(x) |
| del x.incoming |
| del x.outgoing |
| |
| self.transfers = new_transfers |
| |
| def GenerateDigraph(self): |
| print("Generating digraph...") |
| for a in self.transfers: |
| for b in self.transfers: |
| if a is b: continue |
| |
| # If the blocks written by A are read by B, then B needs to go before A. |
| i = a.tgt_ranges.intersect(b.src_ranges) |
| if i: |
| if b.src_name == "__ZERO": |
| # the cost of removing source blocks for the __ZERO domain |
| # is (nearly) zero. |
| size = 0 |
| else: |
| size = i.size() |
| b.goes_before[a] = size |
| a.goes_after[b] = size |
| |
| def FindTransfers(self): |
| self.transfers = [] |
| empty = RangeSet() |
| for tgt_fn, tgt_ranges in self.tgt.file_map.items(): |
| if tgt_fn == "__ZERO": |
| # the special "__ZERO" domain is all the blocks not contained |
| # in any file and that are filled with zeros. We have a |
| # special transfer style for zero blocks. |
| src_ranges = self.src.file_map.get("__ZERO", empty) |
| Transfer(tgt_fn, "__ZERO", tgt_ranges, src_ranges, |
| "zero", self.transfers) |
| continue |
| |
| elif tgt_fn in self.src.file_map: |
| # Look for an exact pathname match in the source. |
| Transfer(tgt_fn, tgt_fn, tgt_ranges, self.src.file_map[tgt_fn], |
| "diff", self.transfers) |
| continue |
| |
| b = os.path.basename(tgt_fn) |
| if b in self.src_basenames: |
| # Look for an exact basename match in the source. |
| src_fn = self.src_basenames[b] |
| Transfer(tgt_fn, src_fn, tgt_ranges, self.src.file_map[src_fn], |
| "diff", self.transfers) |
| continue |
| |
| b = re.sub("[0-9]+", "#", b) |
| if b in self.src_numpatterns: |
| # Look for a 'number pattern' match (a basename match after |
| # all runs of digits are replaced by "#"). (This is useful |
| # for .so files that contain version numbers in the filename |
| # that get bumped.) |
| src_fn = self.src_numpatterns[b] |
| Transfer(tgt_fn, src_fn, tgt_ranges, self.src.file_map[src_fn], |
| "diff", self.transfers) |
| continue |
| |
| Transfer(tgt_fn, None, tgt_ranges, empty, "new", self.transfers) |
| |
| def AbbreviateSourceNames(self): |
| self.src_basenames = {} |
| self.src_numpatterns = {} |
| |
| for k in self.src.file_map.keys(): |
| b = os.path.basename(k) |
| self.src_basenames[b] = k |
| b = re.sub("[0-9]+", "#", b) |
| self.src_numpatterns[b] = k |
| |
| @staticmethod |
| def AssertPartition(total, seq): |
| """Assert that all the RangeSets in 'seq' form a partition of the |
| 'total' RangeSet (ie, they are nonintersecting and their union |
| equals 'total').""" |
| so_far = RangeSet() |
| for i in seq: |
| assert not so_far.overlaps(i) |
| so_far = so_far.union(i) |
| assert so_far == total |
