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.

5 files changed, 24 insertions, 19 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) {
diff --git a/src/other_tools/just_mr/launch.cpp b/src/other_tools/just_mr/launch.cpp
index 0a061031..c085f5be 100644
--- a/src/other_tools/just_mr/launch.cpp
+++ b/src/other_tools/just_mr/launch.cpp
@@ -93,8 +93,9 @@ auto CallJust(std::optional<std::filesystem::path> const& config_file,
 
     std::optional<LockFile> lock{};
     if (subcommand and kKnownJustSubcommands.contains(*subcommand)) {
+        auto const& flags = kKnownJustSubcommands.at(*subcommand);
         // Read the config file if needed
-        if (kKnownJustSubcommands.at(*subcommand).config) {
+        if (flags.config) {
             auto repo_lock =
                 RepositoryGarbageCollector::SharedLock(storage_config);
             if (not repo_lock) {
@@ -128,15 +129,14 @@ auto CallJust(std::optional<std::filesystem::path> const& config_file,
                 return kExitSetupError;
             }
         }
-        use_build_root = kKnownJustSubcommands.at(*subcommand).build_root;
-        use_launcher = kKnownJustSubcommands.at(*subcommand).launch;
-        supports_defines = kKnownJustSubcommands.at(*subcommand).defines;
-        supports_remote = kKnownJustSubcommands.at(*subcommand).remote;
-        supports_remote_properties =
-            kKnownJustSubcommands.at(*subcommand).remote_props;
-        supports_serve = kKnownJustSubcommands.at(*subcommand).serve;
-        supports_dispatch = kKnownJustSubcommands.at(*subcommand).dispatch;
-        does_build = kKnownJustSubcommands.at(*subcommand).does_build;
+        use_build_root = flags.build_root;
+        use_launcher = flags.launch;
+        supports_defines = flags.defines;
+        supports_remote = flags.remote;
+        supports_remote_properties = flags.remote_props;
+        supports_serve = flags.serve;
+        supports_dispatch = flags.dispatch;
+        does_build = flags.does_build;
     }
     // build just command
     std::vector<std::string> cmd = {common_args.just_path->string()};
diff --git a/src/other_tools/just_mr/mirrors.hpp b/src/other_tools/just_mr/mirrors.hpp
index 7480a839..41351bbb 100644
--- a/src/other_tools/just_mr/mirrors.hpp
+++ b/src/other_tools/just_mr/mirrors.hpp
@@ -158,7 +158,7 @@ namespace MirrorsUtils {
             CurlURLHandle::GetHostname(mirror).value_or(std::string{});
         auto it = mirrors_by_hostname.find(hostname);
         if (it != mirrors_by_hostname.end()) {
-            mirrors_by_hostname.at(hostname).emplace_back(mirror);
+            it->second.emplace_back(mirror);
         }
         else {
             // add missing or unknown hostnames to fallback list with key ""
diff --git a/src/other_tools/just_mr/update.cpp b/src/other_tools/just_mr/update.cpp
index e2ed9197..43fd2de6 100644
--- a/src/other_tools/just_mr/update.cpp
+++ b/src/other_tools/just_mr/update.cpp
@@ -24,6 +24,7 @@
 #include <optional>
 #include <thread>
 #include <unordered_map>
+#include <utility>
 #include <vector>
 
 #include "fmt/core.h"
@@ -118,7 +119,8 @@ auto MultiRepoUpdate(std::shared_ptr<Configuration> const& config,
                 return kExitUpdateError;
             }
             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,
                             "Unknown repository type {} for {}",
                             nlohmann::json(repo_type_str).dump(),
@@ -126,7 +128,7 @@ auto MultiRepoUpdate(std::shared_ptr<Configuration> const& config,
                 return kExitUpdateError;
             }
             // only do work if repo is git type
-            if (kCheckoutTypeMap.at(repo_type_str) == CheckoutType::Git) {
+            if (checkout_type_it->second == CheckoutType::Git) {
                 auto repo_desc_repository =
                     (*resolved_repo_desc)->At("repository");
                 if (not repo_desc_repository) {
diff --git a/src/other_tools/repo_map/repos_to_setup_map.cpp b/src/other_tools/repo_map/repos_to_setup_map.cpp
index 4e29ffc2..7aeb69f7 100644
--- a/src/other_tools/repo_map/repos_to_setup_map.cpp
+++ b/src/other_tools/repo_map/repos_to_setup_map.cpp
@@ -502,7 +502,8 @@ void DistdirCheckout(ExpressionPtr const& repo_desc,
         }
         // get repo_type
         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)(fmt::format("DistdirCheckout: Unknown type {} for "
                                   "repository {}",
                                   nlohmann::json(repo_type_str).dump(),
@@ -511,7 +512,7 @@ void DistdirCheckout(ExpressionPtr const& repo_desc,
             return;
         }
         // only do work if repo is archive type
-        if (kCheckoutTypeMap.at(repo_type_str) == CheckoutType::Archive) {
+        if (checkout_type_it->second == CheckoutType::Archive) {
             auto const archive =
                 ParseArchiveContent(*resolved_repo_desc, dist_repo_name);
             if (not archive) {
@@ -794,7 +795,8 @@ auto CreateReposToSetupMap(
             }
             // get repo_type
             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)(
                     fmt::format("Config: Unknown type {} for repository {}",
                                 nlohmann::json(repo_type_str).dump(),
@@ -811,7 +813,7 @@ auto CreateReposToSetupMap(
                               fatal);
                 });
             // do checkout
-            switch (kCheckoutTypeMap.at(repo_type_str)) {
+            switch (checkout_type_it->second) {
                 case CheckoutType::Git: {
                     GitCheckout(*resolved_repo_desc,
                                 std::move(repos),