Fix unzipping when there is a nested directory

Android CTS's `android-cts.zip` has a nested `android-cts/`
subdirectory that would fail in `ExtractOneTo()`.

Bug: b/466404901
Test:
  bazel run cuttlefish/host/commands/cvd:cvd -- \
      fetch \
      --default_build=aosp-android-latest-release/aosp_cf_x86_64_only_phone-userdebug \
      --test_suites_build=aosp-android13-tests-release/test_suites_x86_64 \
      --target_directory=/tmp/fetch-test

Author: jmacnak

base/cvd/cuttlefish/host/commands/cvd/fetch/fetch_context.cc

@@ -111,8 +111,10 @@ Result<void> FetchArtifact::ExtractAll(const std::string& local_path) {
     CF_EXPECT(!absl::StartsWith(member_name, "."));
     CF_EXPECT(!absl::StartsWith(member_name, "/"));
     CF_EXPECT(!absl::StrContains(member_name, "/../"));
-    std::string extract_path = fmt::format("{}/{}", local_path, member_name);
-    CF_EXPECT(ExtractOneTo(member_name, extract_path));
+    if (!CF_EXPECT(zip->EntryIsDirectory(i))) {
+      std::string extract_path = fmt::format("{}/{}", local_path, member_name);
+      CF_EXPECT(ExtractOneTo(member_name, extract_path));
+    }
   }
   return {};
 }
@@ -132,7 +134,8 @@ Result<void> FetchArtifact::ExtractOneTo(const std::string& member_name,
     CF_EXPECT(EnsureDirectoryExists(dir, kRwxAllMode));
   }
 
-  CF_EXPECT(ExtractFile(*zip, member_name, extract_path));
+  CF_EXPECT(ExtractFile(*zip, member_name, extract_path),
+            "Failed to extract " << member_name << " to " << extract_path);
 
   CF_EXPECT(fetch_build_context_.AddFileToConfig(extract_path, artifact_name_,
                                                  local_path));

base/cvd/cuttlefish/host/libs/zip/libzip_cc/archive.cc

@@ -18,6 +18,8 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 #include <string>
 #include <utility>
@@ -88,6 +90,19 @@ Result<uint32_t> ReadableZip::EntryUnixAttributes(uint64_t index) {
   return attributes;
 }
 
+Result<bool> ReadableZip::EntryIsDirectory(uint64_t index) {
+  const uint32_t attributes =
+      CF_EXPECT(EntryUnixAttributes(index),
+                "Failed to get attributes for entry " << index);
+
+  // See
+  //  * https://cs.android.com/android/platform/superproject/main/+/main:build/soong/zip/zip.go;drc=8967d7562557001eb10e216ba7a947fb6054c67c;l=782
+  //  * https://cs.android.com/android/platform/superproject/main/+/main:build/soong/third_party/zip/struct.go;drc=61197364367c9e404c7da6900658f1b16c42d0da;l=225
+  const mode_t mode = (attributes >> 16);
+
+  return S_ISDIR(mode);
+}
+
 Result<SeekableZipSource> ReadableZip::GetFile(const std::string& name) {
   zip_t* raw_zip = CF_EXPECT(raw_.get());
 

base/cvd/cuttlefish/host/libs/zip/libzip_cc/archive.h

@@ -44,6 +44,7 @@ class ReadableZip {
 
   Result<std::string> EntryName(uint64_t index);
   Result<uint32_t> EntryUnixAttributes(uint64_t index);
+  Result<bool> EntryIsDirectory(uint64_t index);
 
   /* Decompresses and extract a file from the archive. */
   Result<SeekableZipSource> GetFile(const std::string& name);