commit c33f5260ea74f64587f51c6b26d8e31d6163a8b1
author Songchun Fan <schfan@google.com> Tue Mar 24 09:15:51 2020 -0700
committer Songchun Fan <schfan@google.com> Tue Mar 24 10:16:49 2020 -0700
tree 204583eb8fb544f7b46bdd712410de7904a6dea2
parent 18c00858d280755790e6199f310c449a03050478

[libziparchive] add an option to start iteration with functor

To reduce the seeks for local file headers in large APK files, we can
specify entry prefix/suffix when we call StartIteration(). However,
some use cases need additional name matches that is outside the
prefix/suffix matches.

Adding a new option to StartIteration, which allows additional functor
that restricts the iteration to customized name matching schemes.

Test: atest ziparchive-tests
BUG: 151676293
Change-Id: Iff45e083b334602f183c05cb39ba521e7070252c

libziparchive/zip_archive.cc

diff --git a/libziparchive/zip_archive.cc b/libziparchive/zip_archive.cc
index afbc5d8..6b6502b 100644
--- a/libziparchive/zip_archive.cc
+++ b/libziparchive/zip_archive.cc
@@ -32,6 +32,7 @@
 #include <unistd.h>
 
 #include <memory>
+#include <optional>
 #include <vector>
 
 #if defined(__APPLE__)
@@ -675,31 +676,40 @@
 struct IterationHandle {
   ZipArchive* archive;
 
-  std::string prefix;
-  std::string suffix;
+  std::function<bool(std::string_view)> matcher;
 
   uint32_t position = 0;
 
-  IterationHandle(ZipArchive* archive, std::string_view in_prefix, std::string_view in_suffix)
-      : archive(archive), prefix(in_prefix), suffix(in_suffix) {}
+  IterationHandle(ZipArchive* archive, std::function<bool(std::string_view)> in_matcher)
+      : archive(archive), matcher(std::move(in_matcher)) {}
+
+  bool Match(std::string_view entry_name) const { return matcher(entry_name); }
 };
 
 int32_t StartIteration(ZipArchiveHandle archive, void** cookie_ptr,
                        const std::string_view optional_prefix,
                        const std::string_view optional_suffix) {
-  if (archive == nullptr || archive->cd_entry_map == nullptr) {
-    ALOGW("Zip: Invalid ZipArchiveHandle");
-    return kInvalidHandle;
-  }
-
   if (optional_prefix.size() > static_cast<size_t>(UINT16_MAX) ||
       optional_suffix.size() > static_cast<size_t>(UINT16_MAX)) {
     ALOGW("Zip: prefix/suffix too long");
     return kInvalidEntryName;
   }
+  auto matcher = [prefix = std::string(optional_prefix),
+                  suffix = std::string(optional_suffix)](std::string_view name) mutable {
+    return android::base::StartsWith(name, prefix) && android::base::EndsWith(name, suffix);
+  };
+  return StartIteration(archive, cookie_ptr, std::move(matcher));
+}
+
+int32_t StartIteration(ZipArchiveHandle archive, void** cookie_ptr,
+                       std::function<bool(std::string_view)> matcher) {
+  if (archive == nullptr || archive->cd_entry_map == nullptr) {
+    ALOGW("Zip: Invalid ZipArchiveHandle");
+    return kInvalidHandle;
+  }
 
   archive->cd_entry_map->ResetIteration();
-  *cookie_ptr = new IterationHandle(archive, optional_prefix, optional_suffix);
+  *cookie_ptr = new IterationHandle(archive, matcher);
   return 0;
 }
 
@@ -749,8 +759,7 @@
   auto entry = archive->cd_entry_map->Next(archive->central_directory.GetBasePtr());
   while (entry != std::pair<std::string_view, uint64_t>()) {
     const auto [entry_name, offset] = entry;
-    if (android::base::StartsWith(entry_name, handle->prefix) &&
-        android::base::EndsWith(entry_name, handle->suffix)) {
+    if (handle->Match(entry_name)) {
       const int error = FindEntry(archive, entry_name, offset, data);
       if (!error && name) {
         *name = entry_name;