refactor BlockDifference into common
Move BlockDifference into common and make its script generation code
more complete, so that it can be use by releasetools.py to do diffs on
baseband images.
Bug: 16984795
Change-Id: Iba9afc1c7755458ce47468b5170672612b2cb4b3
diff --git a/tools/releasetools/blockimgdiff.py b/tools/releasetools/blockimgdiff.py
index 7b01f71..6f94eda 100644
--- a/tools/releasetools/blockimgdiff.py
+++ b/tools/releasetools/blockimgdiff.py
@@ -14,6 +14,8 @@
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-")
@@ -60,6 +62,59 @@
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):
@@ -104,6 +159,10 @@
# 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.
@@ -478,7 +537,12 @@
# 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:
- size = i.size()
+ 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
@@ -491,7 +555,8 @@
# 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, None, tgt_ranges, src_ranges, "zero", self.transfers)
+ Transfer(tgt_fn, "__ZERO", tgt_ranges, src_ranges,
+ "zero", self.transfers)
continue
elif tgt_fn in self.src.file_map: