Merge "Improve the comment in AddSplitTransfers" (cca4a4c9) · Commits · e / os / android_build

tools/releasetools/blockimgdiff.py

+36 −23

Original line number	Diff line number	Diff line
		@@ -1178,9 +1178,22 @@ class BlockImageDiff(object):
		def FindTransfers(self):
		"""Parse the file_map to generate all the transfers."""

		def AddSplitTransfers(tgt_name, src_name, tgt_ranges, src_ranges, style,
		by_id):
		"""Add one or multiple Transfer()s by splitting large files."""
		def AddSplitTransfersWithFixedSizeChunks(tgt_name, src_name, tgt_ranges,
		src_ranges, style, by_id):
		"""Add one or multiple Transfer()s by splitting large files.

		For BBOTA v3, we need to stash source blocks for resumable feature.
		However, with the growth of file size and the shrink of the cache
		partition source blocks are too large to be stashed. If a file occupies
		too many blocks, we split it into smaller pieces by getting multiple
		Transfer()s.

		The downside is that after splitting, we may increase the package size
		since the split pieces don't align well. According to our experiments,
		1/8 of the cache size as the per-piece limit appears to be optimal.
		Compared to the fixed 1024-block limit, it reduces the overall package
		size by 30% for volantis, and 20% for angler and bullhead."""

		pieces = 0
		while (tgt_ranges.size() > max_blocks_per_transfer and
		src_ranges.size() > max_blocks_per_transfer):
		@@ -1207,21 +1220,15 @@ class BlockImageDiff(object):
		self.tgt.RangeSha1(tgt_ranges), self.src.RangeSha1(src_ranges),
		style, by_id)

		def FindZipsAndAddSplitTransfers(tgt_name, src_name, tgt_ranges,
		src_ranges, style, by_id):
		"""Find all the zip archives and add split transfers for the other files.

		For BBOTA v3, we need to stash source blocks for resumable feature.
		However, with the growth of file size and the shrink of the cache
		partition source blocks are too large to be stashed. If a file occupies
		too many blocks, we split it into smaller pieces by getting multiple
		Transfer()s.
		def AddSplitTransfers(tgt_name, src_name, tgt_ranges, src_ranges, style,
		by_id):
		"""Find all the zip files and split the others with a fixed chunk size.

		The downside is that after splitting, we may increase the package size
		since the split pieces don't align well. According to our experiments,
		1/8 of the cache size as the per-piece limit appears to be optimal.
		Compared to the fixed 1024-block limit, it reduces the overall package
		size by 30% for volantis, and 20% for angler and bullhead."""
		This function will construct a list of zip archives, which will later be
		split by imgdiff to reduce the final patch size. For the other files,
		we will plainly split them based on a fixed chunk size with the potential
		patch size penalty.
		"""

		assert style == "diff"

		@@ -1241,8 +1248,8 @@ class BlockImageDiff(object):
		large_apks.append((tgt_name, src_name, tgt_ranges, src_ranges))
		return

		AddSplitTransfers(tgt_name, src_name, tgt_ranges, src_ranges,
		style, by_id)
		AddSplitTransfersWithFixedSizeChunks(tgt_name, src_name, tgt_ranges,
		src_ranges, style, by_id)

		def AddTransfer(tgt_name, src_name, tgt_ranges, src_ranges, style, by_id,
		split=False):
		@@ -1292,7 +1299,7 @@ class BlockImageDiff(object):
		assert tgt_changed + tgt_skipped.size() == tgt_size
		print('%10d %10d (%6.2f%%) %s' % (tgt_skipped.size(), tgt_size,
		tgt_skipped.size() * 100.0 / tgt_size, tgt_name))
		FindZipsAndAddSplitTransfers(
		AddSplitTransfers(
		"%s-skipped" % (tgt_name,),
		"%s-skipped" % (src_name,),
		tgt_skipped, src_skipped, style, by_id)
		@@ -1309,7 +1316,7 @@ class BlockImageDiff(object):
		return

		# Add the transfer(s).
		FindZipsAndAddSplitTransfers(
		AddSplitTransfers(
		tgt_name, src_name, tgt_ranges, src_ranges, style, by_id)

		def ParseAndValidateSplitInfo(patch_size, tgt_ranges, src_ranges,
		@@ -1384,6 +1391,11 @@ class BlockImageDiff(object):
		be valid because the block ranges of src-X & tgt-X will always stay the
		same afterwards; but there's a chance we don't use the patch if we
		convert the "diff" command into "new" or "move" later.

		The split will be attempted by calling imgdiff, which expects the input
		files to be valid zip archives. If imgdiff fails for some reason (i.e.
		holes in the APK file), we will fall back to split the failed APKs into
		fixed size chunks.
		"""

		while True:
		@@ -1412,7 +1424,8 @@ class BlockImageDiff(object):
		print("Failed to create patch between {} and {},"
		" falling back to bsdiff".format(src_name, tgt_name))
		with transfer_lock:
		AddSplitTransfers(tgt_name, src_name, tgt_ranges, src_ranges,
		AddSplitTransfersWithFixedSizeChunks(tgt_name, src_name,
		tgt_ranges, src_ranges,
		"diff", self.transfers)
		continue