Merge "Implement a custom deflate sink function for bspatch"
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp
index 702a624..df75f98 100644
--- a/applypatch/imgpatch.cpp
+++ b/applypatch/imgpatch.cpp
@@ -26,12 +26,14 @@
#include <sys/stat.h>
#include <unistd.h>
+#include <memory>
#include <string>
#include <vector>
+#include <android-base/logging.h>
+#include <android-base/memory.h>
#include <applypatch/applypatch.h>
#include <applypatch/imgdiff.h>
-#include <android-base/memory.h>
#include <openssl/sha.h>
#include <zlib.h>
@@ -43,6 +45,86 @@
return android::base::get_unaligned<int32_t>(address);
}
+// This function is a wrapper of ApplyBSDiffPatch(). It has a custom sink function to deflate the
+// patched data and stream the deflated data to output.
+static bool ApplyBSDiffPatchAndStreamOutput(const uint8_t* src_data, size_t src_len,
+ const Value* patch, size_t patch_offset,
+ const char* deflate_header, SinkFn sink, SHA_CTX* ctx) {
+ size_t expected_target_length = static_cast<size_t>(Read8(deflate_header + 32));
+ int level = Read4(deflate_header + 40);
+ int method = Read4(deflate_header + 44);
+ int window_bits = Read4(deflate_header + 48);
+ int mem_level = Read4(deflate_header + 52);
+ int strategy = Read4(deflate_header + 56);
+
+ std::unique_ptr<z_stream, decltype(&deflateEnd)> strm(new z_stream(), deflateEnd);
+ strm->zalloc = Z_NULL;
+ strm->zfree = Z_NULL;
+ strm->opaque = Z_NULL;
+ strm->avail_in = 0;
+ strm->next_in = nullptr;
+ int ret = deflateInit2(strm.get(), level, method, window_bits, mem_level, strategy);
+ if (ret != Z_OK) {
+ LOG(ERROR) << "Failed to init uncompressed data deflation: " << ret;
+ return false;
+ }
+
+ // Define a custom sink wrapper that feeds to bspatch. It deflates the available patch data on
+ // the fly and outputs the compressed data to the given sink.
+ size_t actual_target_length = 0;
+ size_t total_written = 0;
+ static constexpr size_t buffer_size = 32768;
+ auto compression_sink = [&](const uint8_t* data, size_t len) -> size_t {
+ // The input patch length for an update never exceeds INT_MAX.
+ strm->avail_in = len;
+ strm->next_in = data;
+ do {
+ std::vector<uint8_t> buffer(buffer_size);
+ strm->avail_out = buffer_size;
+ strm->next_out = buffer.data();
+ if (actual_target_length + len < expected_target_length) {
+ ret = deflate(strm.get(), Z_NO_FLUSH);
+ } else {
+ ret = deflate(strm.get(), Z_FINISH);
+ }
+ if (ret != Z_OK && ret != Z_STREAM_END) {
+ LOG(ERROR) << "Failed to deflate stream: " << ret;
+ // zero length indicates an error in the sink function of bspatch().
+ return 0;
+ }
+
+ size_t have = buffer_size - strm->avail_out;
+ total_written += have;
+ if (sink(buffer.data(), have) != have) {
+ LOG(ERROR) << "Failed to write " << have << " compressed bytes to output.";
+ return 0;
+ }
+ if (ctx) SHA1_Update(ctx, buffer.data(), have);
+ } while ((strm->avail_in != 0 || strm->avail_out == 0) && ret != Z_STREAM_END);
+
+ actual_target_length += len;
+ return len;
+ };
+
+ if (ApplyBSDiffPatch(src_data, src_len, patch, patch_offset, compression_sink, nullptr) != 0) {
+ return false;
+ }
+
+ if (ret != Z_STREAM_END) {
+ LOG(ERROR) << "ret is expected to be Z_STREAM_END, but it's " << ret;
+ return false;
+ }
+
+ if (expected_target_length != actual_target_length) {
+ LOG(ERROR) << "target length is expected to be " << expected_target_length << ", but it's "
+ << actual_target_length;
+ return false;
+ }
+ LOG(DEBUG) << "bspatch writes " << total_written << " bytes in total to streaming output.";
+
+ return true;
+}
+
int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const unsigned char* patch_data,
size_t patch_size, SinkFn sink) {
Value patch(VAL_BLOB, std::string(reinterpret_cast<const char*>(patch_data), patch_size));
@@ -137,12 +219,6 @@
size_t src_len = static_cast<size_t>(Read8(deflate_header + 8));
size_t patch_offset = static_cast<size_t>(Read8(deflate_header + 16));
size_t expanded_len = static_cast<size_t>(Read8(deflate_header + 24));
- size_t target_len = static_cast<size_t>(Read8(deflate_header + 32));
- int level = Read4(deflate_header + 40);
- int method = Read4(deflate_header + 44);
- int windowBits = Read4(deflate_header + 48);
- int memLevel = Read4(deflate_header + 52);
- int strategy = Read4(deflate_header + 56);
if (src_start + src_len > old_size) {
printf("source data too short\n");
@@ -199,60 +275,12 @@
}
}
- // Next, apply the bsdiff patch (in memory) to the uncompressed data.
- std::vector<uint8_t> uncompressed_target_data;
- // TODO: replace the custom sink function passed into ApplyBSDiffPatch so that it wraps the
- // given sink function to stream output to save memory.
- if (ApplyBSDiffPatch(expanded_source.data(), expanded_len, patch, patch_offset,
- [&uncompressed_target_data](const uint8_t* data, size_t len) {
- uncompressed_target_data.insert(uncompressed_target_data.end(), data, data + len);
- return len;
- }, nullptr) != 0) {
- return -1;
- }
- if (uncompressed_target_data.size() != target_len) {
- printf("expected target len to be %zu, but it's %zu\n", target_len,
- uncompressed_target_data.size());
+ if (!ApplyBSDiffPatchAndStreamOutput(expanded_source.data(), expanded_len, patch,
+ patch_offset, deflate_header, sink, ctx)) {
+ LOG(ERROR) << "Fail to apply streaming bspatch.";
return -1;
}
- // Now compress the target data and append it to the output.
-
- // we're done with the expanded_source data buffer, so we'll
- // reuse that memory to receive the output of deflate.
- if (expanded_source.size() < 32768U) {
- expanded_source.resize(32768U);
- }
-
- {
- std::vector<unsigned char>& temp_data = expanded_source;
-
- // now the deflate stream
- z_stream strm;
- strm.zalloc = Z_NULL;
- strm.zfree = Z_NULL;
- strm.opaque = Z_NULL;
- strm.avail_in = uncompressed_target_data.size();
- strm.next_in = uncompressed_target_data.data();
- int ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy);
- if (ret != Z_OK) {
- printf("failed to init uncompressed data deflation: %d\n", ret);
- return -1;
- }
- do {
- strm.avail_out = temp_data.size();
- strm.next_out = temp_data.data();
- ret = deflate(&strm, Z_FINISH);
- size_t have = temp_data.size() - strm.avail_out;
-
- if (sink(temp_data.data(), have) != have) {
- printf("failed to write %zd compressed bytes to output\n", have);
- return -1;
- }
- if (ctx) SHA1_Update(ctx, temp_data.data(), have);
- } while (ret != Z_STREAM_END);
- deflateEnd(&strm);
- }
} else {
printf("patch chunk %d is unknown type %d\n", i, type);
return -1;
