Add discovery logic for zip archives from the build system

Bug: b/470161243

Author: Databean

base/cvd/cuttlefish/host/commands/assemble_cvd/android_build/BUILD.bazel

@@ -28,3 +28,19 @@ cf_cc_library(
         "@fmt",
     ],
 )
+
+cf_cc_library(
+    name = "find_build_archive",
+    srcs = ["find_build_archive.cc"],
+    hdrs = ["find_build_archive.h"],
+    deps = [
+        "//cuttlefish/common/libs/utils:files",
+        "//cuttlefish/common/libs/utils:result",
+        "//cuttlefish/host/libs/config:build_archive",
+        "//cuttlefish/host/libs/config:fetcher_config",
+        "//cuttlefish/host/libs/config:file_source",
+        "//cuttlefish/host/libs/zip:zip_file",
+        "//cuttlefish/host/libs/zip/libzip_cc:archive",
+        "@abseil-cpp//absl/strings",
+    ],
+)

base/cvd/cuttlefish/host/commands/assemble_cvd/android_build/find_build_archive.cc

@@ -0,0 +1,88 @@
+//
+// Copyright (C) 2025 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 "cuttlefish/host/commands/assemble_cvd/android_build/find_build_archive.h"
+
+#include <optional>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/match.h"
+
+#include "cuttlefish/common/libs/utils/files.h"
+#include "cuttlefish/common/libs/utils/result.h"
+#include "cuttlefish/host/libs/config/build_archive.h"
+#include "cuttlefish/host/libs/config/fetcher_config.h"
+#include "cuttlefish/host/libs/config/file_source.h"
+#include "cuttlefish/host/libs/zip/libzip_cc/archive.h"
+#include "cuttlefish/host/libs/zip/zip_file.h"
+
+namespace cuttlefish {
+namespace {
+
+bool NameMatches(std::string_view name, std::string_view pattern) {
+  return absl::EndsWith(name, ".zip") && absl::StrContains(name, pattern);
+}
+
+}  // namespace
+
+Result<BuildArchive> FindBuildArchive(const FetcherConfig& config,
+                                      FileSource source,
+                                      std::string_view pattern) {
+  std::optional<std::string_view> archive_name;
+  for (const auto& [file_name, cvd_file] : config.get_cvd_files()) {
+    if (cvd_file.source != source) {
+      continue;
+    }
+    for (std::string_view name :
+         {cvd_file.archive_source, cvd_file.file_path}) {
+      if (NameMatches(name, pattern)) {
+        CF_EXPECTF(!archive_name.has_value() || *archive_name == name,
+                   "Multiple files match '{}': '{}' and '{}'", pattern,
+                   *archive_name, name);
+        archive_name = name;
+      }
+    }
+  }
+  CF_EXPECTF(archive_name.has_value(), "No archive found with '{}'", pattern);
+  return CF_EXPECT(
+      BuildArchive::FromFetcherConfig(config, source, *archive_name));
+}
+
+Result<BuildArchive> FindBuildArchive(const std::string& directory_path,
+                                      std::string_view pattern) {
+  std::vector<std::string> contents =
+      CF_EXPECT(DirectoryContents(directory_path));
+
+  std::optional<std::string_view> archive_name;
+  for (std::string_view member : contents) {
+    if (!NameMatches(member, pattern)) {
+      continue;
+    }
+    CF_EXPECTF(!archive_name.has_value(),
+               "Found two matching files for '{}' in '{}': '{}' and '{}'",
+               pattern, directory_path, *archive_name, member);
+    archive_name = member;
+  }
+  CF_EXPECTF(archive_name.has_value(), "Could not find file with '{}' in '{}'",
+             pattern, directory_path);
+
+  ReadableZip zip = CF_EXPECT(ZipOpenRead(std::string(*archive_name)));
+  return CF_EXPECT(BuildArchive::FromZip(std::move(zip)));
+}
+
+}  // namespace cuttlefish

base/cvd/cuttlefish/host/commands/assemble_cvd/android_build/find_build_archive.h

@@ -0,0 +1,42 @@
+//
+// Copyright (C) 2025 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.
+
+#pragma once
+
+#include <string>
+#include <string_view>
+
+#include "cuttlefish/common/libs/utils/result.h"
+#include "cuttlefish/host/libs/config/build_archive.h"
+#include "cuttlefish/host/libs/config/fetcher_config.h"
+#include "cuttlefish/host/libs/config/file_source.h"
+
+namespace cuttlefish {
+
+/**
+ * Scan a `FetcherConfig` for an archive containing the substring `pattern`.
+ * This could be a zip file still present, or the extracted contents of a zip
+ * file that was downloaded.
+ */
+Result<BuildArchive> FindBuildArchive(const FetcherConfig&, FileSource,
+                                      std::string_view pattern);
+/**
+ * Scan the contents of `directory_path` to find a file whose name contains
+ * `pattern` as a substring, and is a zip archive.
+ */
+Result<BuildArchive> FindBuildArchive(const std::string& directory_path,
+                                      std::string_view pattern);
+
+}  // namespace cuttlefish