Avoid unnecessary work in accessing container entries

- in sequence containers, use operator[] instead of .at() when
accessing indices guaranteed to be in bound;
- in associative containers, prefer .find() and reusing the
returned const iterator to using .contains() and .at(); while
there, make any so obtained iterators const if they are read-only.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/other_tools/just_mr/fetch.cpp b/src/other_tools/just_mr/fetch.cpp
index 3585d2f3..a7afc575 100644
--- a/src/other_tools/just_mr/fetch.cpp
+++ b/src/other_tools/just_mr/fetch.cpp
@@ -223,7 +223,8 @@ auto MultiRepoFetch(std::shared_ptr<Configuration> const& config,
                 return kExitFetchError;
             }
             auto repo_type_str = repo_type->get()->String();
-            if (not kCheckoutTypeMap.contains(repo_type_str)) {
+            auto const checkout_type_it = kCheckoutTypeMap.find(repo_type_str);
+            if (checkout_type_it == kCheckoutTypeMap.end()) {
                 Logger::Log(LogLevel::Error,
                             "Config: Unknown repository type {} for {}",
                             nlohmann::json(repo_type_str).dump(),
@@ -231,7 +232,7 @@ auto MultiRepoFetch(std::shared_ptr<Configuration> const& config,
                 return kExitFetchError;
             }
             // only do work if repo is archive or git tree type
-            switch (kCheckoutTypeMap.at(repo_type_str)) {
+            switch (checkout_type_it->second) {
                 case CheckoutType::Archive: {
                     auto logger = std::make_shared<AsyncMapConsumerLogger>(
                         [&repo_name](std::string const& msg, bool fatal) {