Implement ZipWriter for quickly writing ZipFiles.

The ZipWriter implementation exposes a stateful interface that allows
bytes of data to be streamed in as they arrive. ZipEntries can be
compressed and/or aligned on a 32-bit boundary for mmapping at runtime.

Change-Id: I43ac9e661aa5022f00d9e12b247c4314d61c441c

1 files changed, 262 insertions, 0 deletions

diff --git a/libziparchive/zip_writer.cc b/libziparchive/zip_writer.cc
new file mode 100644
index 000000000..de75d1ede
--- /dev/null
+++ b/libziparchive/zip_writer.cc
@@ -0,0 +1,262 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include "entry_name_utils-inl.h"
+#include "zip_archive_common.h"
+#include "ziparchive/zip_writer.h"
+
+#include <cassert>
+#include <cstdio>
+#include <memory>
+#include <zlib.h>
+
+/* Zip compression methods we support */
+enum {
+  kCompressStored     = 0,        // no compression
+  kCompressDeflated   = 8,        // standard deflate
+};
+
+// No error, operation completed successfully.
+static const int32_t kNoError = 0;
+
+// The ZipWriter is in a bad state.
+static const int32_t kInvalidState = -1;
+
+// There was an IO error while writing to disk.
+static const int32_t kIoError = -2;
+
+// The zip entry name was invalid.
+static const int32_t kInvalidEntryName = -3;
+
+static const char* sErrorCodes[] = {
+    "Invalid state",
+    "IO error",
+    "Invalid entry name",
+};
+
+const char* ZipWriter::ErrorCodeString(int32_t error_code) {
+  if (error_code < 0 && (-error_code) < static_cast<int32_t>(arraysize(sErrorCodes))) {
+    return sErrorCodes[-error_code];
+  }
+  return nullptr;
+}
+
+ZipWriter::ZipWriter(FILE* f) : file_(f), current_offset_(0), state_(State::kWritingZip) {
+}
+
+ZipWriter::ZipWriter(ZipWriter&& writer) : file_(writer.file_),
+                                           current_offset_(writer.current_offset_),
+                                           state_(writer.state_),
+                                           files_(std::move(writer.files_)) {
+  writer.file_ = nullptr;
+  writer.state_ = State::kError;
+}
+
+ZipWriter& ZipWriter::operator=(ZipWriter&& writer) {
+  file_ = writer.file_;
+  current_offset_ = writer.current_offset_;
+  state_ = writer.state_;
+  files_ = std::move(writer.files_);
+  writer.file_ = nullptr;
+  writer.state_ = State::kError;
+  return *this;
+}
+
+int32_t ZipWriter::HandleError(int32_t error_code) {
+  state_ = State::kError;
+  return error_code;
+}
+
+int32_t ZipWriter::StartEntry(const char* path, size_t flags) {
+  return StartEntryWithTime(path, flags, time_t());
+}
+
+static void ExtractTimeAndDate(time_t when, uint16_t* out_time, uint16_t* out_date) {
+  /* round up to an even number of seconds */
+  when = static_cast<time_t>((static_cast<unsigned long>(when) + 1) & (~1));
+
+  struct tm* ptm;
+#if !defined(_WIN32)
+    struct tm tm_result;
+    ptm = localtime_r(&when, &tm_result);
+#else
+    ptm = localtime(&when);
+#endif
+
+  int year = ptm->tm_year;
+  if (year < 80) {
+    year = 80;
+  }
+
+  *out_date = (year - 80) << 9 | (ptm->tm_mon + 1) << 5 | ptm->tm_mday;
+  *out_time = ptm->tm_hour << 11 | ptm->tm_min << 5 | ptm->tm_sec >> 1;
+}
+
+int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t time) {
+  if (state_ != State::kWritingZip) {
+    return kInvalidState;
+  }
+
+  FileInfo fileInfo = {};
+  fileInfo.path = std::string(path);
+  fileInfo.local_file_header_offset = current_offset_;
+
+  if (!IsValidEntryName(reinterpret_cast<const uint8_t*>(fileInfo.path.data()),
+                       fileInfo.path.size())) {
+    return kInvalidEntryName;
+  }
+
+  LocalFileHeader header = {};
+  header.lfh_signature = LocalFileHeader::kSignature;
+
+  // Set this flag to denote that a DataDescriptor struct will appear after the data,
+  // containing the crc and size fields.
+  header.gpb_flags |= kGPBDDFlagMask;
+
+  // For now, ignore the ZipWriter::kCompress flag.
+  fileInfo.compression_method = kCompressStored;
+  header.compression_method = fileInfo.compression_method;
+
+  ExtractTimeAndDate(time, &fileInfo.last_mod_time, &fileInfo.last_mod_date);
+  header.last_mod_time = fileInfo.last_mod_time;
+  header.last_mod_date = fileInfo.last_mod_date;
+
+  header.file_name_length = fileInfo.path.size();
+
+  off64_t offset = current_offset_ + sizeof(header) + fileInfo.path.size();
+  if ((flags & ZipWriter::kAlign32) && (offset & 0x03)) {
+    // Pad the extra field so the data will be aligned.
+    uint16_t padding = 4 - (offset % 4);
+    header.extra_field_length = padding;
+    offset += padding;
+  }
+
+  if (fwrite(&header, sizeof(header), 1, file_) != 1) {
+    return HandleError(kIoError);
+  }
+
+  if (fwrite(path, sizeof(*path), fileInfo.path.size(), file_) != fileInfo.path.size()) {
+    return HandleError(kIoError);
+  }
+
+  if (fwrite("\0\0\0", 1, header.extra_field_length, file_) != header.extra_field_length) {
+    return HandleError(kIoError);
+  }
+
+  files_.emplace_back(std::move(fileInfo));
+
+  current_offset_ = offset;
+  state_ = State::kWritingEntry;
+  return kNoError;
+}
+
+int32_t ZipWriter::WriteBytes(const void* data, size_t len) {
+  if (state_ != State::kWritingEntry) {
+    return HandleError(kInvalidState);
+  }
+
+  FileInfo& currentFile = files_.back();
+  if (currentFile.compression_method & kCompressDeflated) {
+    // TODO(adamlesinski): Implement compression using zlib deflate.
+    assert(false);
+  } else {
+    if (fwrite(data, 1, len, file_) != len) {
+      return HandleError(kIoError);
+    }
+    currentFile.crc32 = crc32(currentFile.crc32, reinterpret_cast<const Bytef*>(data), len);
+    currentFile.compressed_size += len;
+    current_offset_ += len;
+  }
+
+  currentFile.uncompressed_size += len;
+  return kNoError;
+}
+
+int32_t ZipWriter::FinishEntry() {
+  if (state_ != State::kWritingEntry) {
+    return kInvalidState;
+  }
+
+  const uint32_t sig = DataDescriptor::kOptSignature;
+  if (fwrite(&sig, sizeof(sig), 1, file_) != 1) {
+    state_ = State::kError;
+    return kIoError;
+  }
+
+  FileInfo& currentFile = files_.back();
+  DataDescriptor dd = {};
+  dd.crc32 = currentFile.crc32;
+  dd.compressed_size = currentFile.compressed_size;
+  dd.uncompressed_size = currentFile.uncompressed_size;
+  if (fwrite(&dd, sizeof(dd), 1, file_) != 1) {
+    return HandleError(kIoError);
+  }
+
+  current_offset_ += sizeof(DataDescriptor::kOptSignature) + sizeof(dd);
+  state_ = State::kWritingZip;
+  return kNoError;
+}
+
+int32_t ZipWriter::Finish() {
+  if (state_ != State::kWritingZip) {
+    return kInvalidState;
+  }
+
+  off64_t startOfCdr = current_offset_;
+  for (FileInfo& file : files_) {
+    CentralDirectoryRecord cdr = {};
+    cdr.record_signature = CentralDirectoryRecord::kSignature;
+    cdr.gpb_flags |= kGPBDDFlagMask;
+    cdr.compression_method = file.compression_method;
+    cdr.last_mod_time = file.last_mod_time;
+    cdr.last_mod_date = file.last_mod_date;
+    cdr.crc32 = file.crc32;
+    cdr.compressed_size = file.compressed_size;
+    cdr.uncompressed_size = file.uncompressed_size;
+    cdr.file_name_length = file.path.size();
+    cdr.local_file_header_offset = file.local_file_header_offset;
+    if (fwrite(&cdr, sizeof(cdr), 1, file_) != 1) {
+      return HandleError(kIoError);
+    }
+
+    if (fwrite(file.path.data(), 1, file.path.size(), file_) != file.path.size()) {
+      return HandleError(kIoError);
+    }
+
+    current_offset_ += sizeof(cdr) + file.path.size();
+  }
+
+  EocdRecord er = {};
+  er.eocd_signature = EocdRecord::kSignature;
+  er.disk_num = 1;
+  er.cd_start_disk = 1;
+  er.num_records_on_disk = files_.size();
+  er.num_records = files_.size();
+  er.cd_size = current_offset_ - startOfCdr;
+  er.cd_start_offset = startOfCdr;
+
+  if (fwrite(&er, sizeof(er), 1, file_) != 1) {
+    return HandleError(kIoError);
+  }
+
+  if (fflush(file_) != 0) {
+    return HandleError(kIoError);
+  }
+
+  current_offset_ += sizeof(er);
+  state_ = State::kDone;
+  return kNoError;
+}