New Zip::ZipFromMemory API.

third_party/zlib/google/zip_reader.h

 // 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 THIRD_PARTY_ZLIB_GOOGLE_ZIP_READER_H_
 #define THIRD_PARTY_ZLIB_GOOGLE_ZIP_READER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
@@ skipping 17 matching lines @@
 // look like:
 //
 //   ZipReader reader;
 //   reader.Open(zip_file_path);
 //   while (reader.HasMore()) {
 //     reader.OpenCurrentEntryInZip();
 //     reader.ExtractCurrentEntryToDirectory(output_directory_path);
 //     reader.AdvanceToNextEntry();
 //   }
 //
-// For simplicty, error checking is omitted in the example code above. The
+// For simplicity, 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 LocateAndOpenEntry().
 //
 class ZipReader {
  public:
   // A callback that is called when the operation is successful.
   typedef base::Closure SuccessCallback;
   // A callback that is called when the operation fails.
@@ skipping 124 matching lines @@
   // timestamp is not valid, the timestamp will be set to the current time.
   bool ExtractCurrentEntryIntoDirectory(
       const base::FilePath& output_directory_path);
 
 #if defined(OS_POSIX)
   // Extracts the current entry by writing directly to a file descriptor.
   // Does not close the file descriptor. Returns true on success.
   bool ExtractCurrentEntryToFd(int fd);
 #endif
 
+  // Extracts the current entry into memory. If the current entry is a directory
+  // the |output| parameter is set to the empty string. If the current entry is
+  // a file, the |output| parameter is filled with its contents. Returns true on
+  // success. OpenCurrentEntryInZip() must be called beforehand.
+  // Note: the |output| parameter can be filled with a big amount of data, avoid
+  // passing it around by value, but by reference or pointer.
+  // Note that EntryInfo::original_size() can return a different value than the
+  // real size of the uncompressed contents. Therefore, to prevent excessive
+  // memory usage, the maximum amount of data to read has to be specified in
+  // |max_read_bytes|. If the real size of the uncompressed data is bigger than
+  // max_read_bytes then false is returned. |max_read_bytes| must be positive
+  // non-zero.

[hshi1, 2014/03/19 17:33:27]

nit: "positive non-zero" is redundant, just "positive" is sufficient.

+  bool ExtractCurrentEntryToString(
+      int max_read_bytes,

[hshi1, 2014/03/19 17:33:27]

question: this seems to assume that data size cannot exceed 0x7fffffff bytes?

[João Eiras, 2014/03/20 13:52:45]

size_t would be better, yes, though I wonder would want to read more than
2gigabytes into memory ? :) Still, std::string is limited by
std::string::max_size(), which is close to 2^32 or 2^64.

+      std::string* output) const;
+
   // Returns the current entry info. Returns NULL if the current entry is
   // not yet opened. OpenCurrentEntryInZip() must be called beforehand.
   EntryInfo* current_entry_info() const {
     return current_entry_info_.get();
   }
 
   // Returns the number of entries in the zip file.
   // Open() must be called beforehand.
   int num_entries() const { return num_entries_; }
 
@@ skipping 18 matching lines @@
   scoped_ptr<EntryInfo> current_entry_info_;
 
   base::WeakPtrFactory<ZipReader> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ZipReader);
 };
 
 }  // namespace zip
 
 #endif  // THIRD_PARTY_ZLIB_GOOGLE_ZIP_READER_H_