zip: Add ZipReader and rework Unzip() using the new class.

chrome/common/zip_reader.h

Index: chrome/common/zip_reader.h
diff --git a/chrome/common/zip_reader.h b/chrome/common/zip_reader.h
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index 0000000000000000000000000000000000000000..4083c10115c70ae4290bfc00cb6f8475171a2e0f
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+++ b/chrome/common/zip_reader.h
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+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_COMMON_ZIP_READER_H_
+#define CHROME_COMMON_ZIP_READER_H_
+#pragma once
+
+#include <string>
+
+#include "base/file_path.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time.h"
+#include "third_party/zlib/contrib/minizip/unzip.h"
+
+namespace zip {
+
+// This class is used for reading zip files. A typical use case of this
+// class is to scan files in a zip file and extract them. The code will
+// look like:
+//
+//   ZipReader reader;
+//   reader.Open(zip_file_path);
+//   while (reader.HasMore()) {
+//     reader.OpenCurrentFileInZip();
+//     reader.ExtractCurrentFileToDirectory(output_directory_path);
+//     reader.AdvanceToNextFile();
+//   }
+//
+// For simplicty, error checking is omitted in the example code above. The
+// production code should check return values from all of these functions.
+//
+// This calls can also be used for random access of contents in a zip file
+// using LocateAndOpenFile().
+//
+class ZipReader {

[Aaron Boodman, 2011/11/09 08:00:40]

Nice API.

[satorux1, 2011/11/10 08:00:56]

Thanks!

+ public:
+  // This class represents information of a file in a zip file.
+  class FileInfo {
+   public:
+    FileInfo(const std::string& filename_in_zip,
+             const unz_file_info& raw_file_info);
+
+    // Returns the file path.

[Aaron Boodman, 2011/11/09 08:00:40]

It would be nice to indicate whether they are prefixed with '/' for those who
are unfamiliar with the intricacies of zip.

[satorux1, 2011/11/10 08:00:56]

Done. This comment made me to add a new evil zip file that contains file names
starting with /, and a test for it.

+    const FilePath& file_path() const { return file_path_; }
+
+    // Returns the size of the original file (i.e. after uncompressed).
+    const int64 original_size() const { return original_size_; }
+
+    // Returns the last modified time.
+    const base::Time last_modified() const { return last_modified_; }
+
+    // Returns true if the file is a directory.
+    bool is_directory() const { return is_directory_; }
+
+    // Returns true if the file is unsafe, like having ".." in its file
+    // name or invalid UTF-8 characters.
+    bool is_unsafe() const { return is_unsafe_; }
+
+   private:
+    const FilePath file_path_;
+    int64 original_size_;
+    base::Time last_modified_;
+    bool is_directory_;
+    bool is_unsafe_;
+    DISALLOW_COPY_AND_ASSIGN(FileInfo);
+  };
+
+  ZipReader();
+  ~ZipReader();
+
+  // Opens the zip file specified by |zip_file_path|. Returns true on
+  // success.
+  bool Open(const FilePath& zip_file_path);
+
+  // Closes the currently opened zip file. This function is called in the
+  // destructor of the class, so you usually don't need to call this.
+  void Close();
+
+  // Returns true if there is at least one file to read. This function is
+  // used to scan files with AdvanceToNextFile(), like:
+  //
+  // while (reader.HasMore()) {
+  //   // Do something with the current file here.
+  //   reader.AdvanceToNextFile();
+  // }
+  bool HasMore();
+
+  // Advances the next file. Returns true on success.
+  bool AdvanceToNextFile();
+
+  // Opens the current file in the zip file. On success, returns true and
+  // updates the the current file state (i.e. current_file_info() is
+  // updated). This function should be called before operations over the
+  // current file like ExtractCurrentFileToFile().
+  //
+  // Note that there is no CloseCurrentFileInZip(). The the current file
+  // state is reset automatically as needed.
+  bool OpenCurrentFileInZip();
+
+  // Locates a file in the zip file and opens it. Returns true on success.
+  // This function internally calls OpenCurrentFileInZip() on success.
+  // On failure, current_file_info() becomes NULL.
+  bool LocateAndOpenFile(const FilePath& path_in_zip);
+
+  // Extracts the current file to the given output file path. If the
+  // current file is a directory, just creates a directory
+  // instead. Returns true on success. OpenCurrentFileInZip() must be
+  // called beforehand.
+  //
+  // This function does not preserve the timestamp of the original file.
+  bool ExtractCurrentFileToFile(const FilePath& output_file_path);

[Aaron Boodman, 2011/11/09 08:00:40]

Throughout the API, consider using the term 'entry' instead of 'file' for the
items inside the zip. I think that makes it more clear that it might represent a
directory or a file.

[satorux1, 2011/11/10 08:00:56]

Good idea. Changed accordingly.

+
+  // Extracts the current file to the given output directory path using
+  // ExtractCurrentFileToFile(). Sub directories are created as needed
+  // based on the file path of the current file. For example, if the file
+  // path in zip is "foo/bar.txt", and the output directory is "output",
+  // "output/foo/bar.txt" will be created.
+  //
+  // Returns true on success. OpenCurrentFileInZip() must be called
+  // beforehand.
+  bool ExtractCurrentFileToDirectory(const FilePath& output_directory_path);

[Aaron Boodman, 2011/11/09 08:00:40]

Maybe "ExtractCurrentEntryIntoDirectory" ("into" instead of "to") to try and
make clear that you're not transforming the current entry into a directory ...
but just placing it into one.

[satorux1, 2011/11/10 08:00:56]

Done.

+
+  // Returns the current file info. Returns NULL if the current file is
+  // not yet opened. OpenCurrentFileInZip() must be called beforehand.
+  FileInfo* current_file_info() const {
+    return current_file_info_.get();
+  }
+
+  // Returns the number of files in the zip file.
+  // Open() must be called beforehand.
+  int num_files() const { return num_files_; }
+
+ private:
+  unzFile zip_file_;
+  int num_files_;
+  bool reached_end_;
+  scoped_ptr<FileInfo> current_file_info_;

[Aaron Boodman, 2011/11/09 08:00:40]

Call the DISALLOW_COPY_AND_ASSIGN macro from basictypes.h here.

[satorux1, 2011/11/10 08:00:56]

Good catch.  Added.

+};
+
+}  // namespace zip
+
+#endif  // CHROME_COMMON_ZIP_READER_H_