Merge pull request #9794 from hercules-ci/queryPathInfoFromClientCache

refactor: Extract `Store::queryPathInfoFromClientCache`
NixOS · Jan 19, 2024 · 382fa51 · 382fa51
2 parents e6e160a + d19627e
commit 382fa51
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Showing 2 changed files with 52 additions and 24 deletions.
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
@@ -686,38 +686,56 @@ static bool goodStorePath(const StorePath & expected, const StorePath & actual)
 }
 
 
-void Store::queryPathInfo(const StorePath & storePath,
-    Callback<ref<const ValidPathInfo>> callback) noexcept
+std::optional<std::shared_ptr<const ValidPathInfo>> Store::queryPathInfoFromClientCache(const StorePath & storePath)
 {
     auto hashPart = std::string(storePath.hashPart());
 
-    try {
-        {
-            auto res = state.lock()->pathInfoCache.get(std::string(storePath.to_string()));
-            if (res && res->isKnownNow()) {
-                stats.narInfoReadAverted++;
-                if (!res->didExist())
-                    throw InvalidPath("path '%s' is not valid", printStorePath(storePath));
-                return callback(ref<const ValidPathInfo>(res->value));
-            }
+    {
+        auto res = state.lock()->pathInfoCache.get(std::string(storePath.to_string()));
+        if (res && res->isKnownNow()) {
+            stats.narInfoReadAverted++;
+            if (res->didExist())
+                return std::make_optional(res->value);
+            else
+                return std::make_optional(nullptr);
         }
+    }
 
-        if (diskCache) {
-            auto res = diskCache->lookupNarInfo(getUri(), hashPart);
-            if (res.first != NarInfoDiskCache::oUnknown) {
-                stats.narInfoReadAverted++;
-                {
-                    auto state_(state.lock());
-                    state_->pathInfoCache.upsert(std::string(storePath.to_string()),
-                        res.first == NarInfoDiskCache::oInvalid ? PathInfoCacheValue{} : PathInfoCacheValue{ .value = res.second });
-                    if (res.first == NarInfoDiskCache::oInvalid ||
-                        !goodStorePath(storePath, res.second->path))
-                        throw InvalidPath("path '%s' is not valid", printStorePath(storePath));
-                }
-                return callback(ref<const ValidPathInfo>(res.second));
+    if (diskCache) {
+        auto res = diskCache->lookupNarInfo(getUri(), hashPart);
+        if (res.first != NarInfoDiskCache::oUnknown) {
+            stats.narInfoReadAverted++;
+            {
+                auto state_(state.lock());
+                state_->pathInfoCache.upsert(std::string(storePath.to_string()),
+                    res.first == NarInfoDiskCache::oInvalid ? PathInfoCacheValue{} : PathInfoCacheValue{ .value = res.second });
+                if (res.first == NarInfoDiskCache::oInvalid ||
+                    !goodStorePath(storePath, res.second->path))
+                    return std::make_optional(nullptr);
             }
+            assert(res.second);
+            return std::make_optional(res.second);
         }
+    }
+
+    return std::nullopt;
+}
+
 
+void Store::queryPathInfo(const StorePath & storePath,
+    Callback<ref<const ValidPathInfo>> callback) noexcept
+{
+    auto hashPart = std::string(storePath.hashPart());
+
+    try {
+        auto r = queryPathInfoFromClientCache(storePath);
+        if (r.has_value()) {
+            std::shared_ptr<const ValidPathInfo> & info = *r;
+            if (info)
+                return callback(ref(info));
+            else
+                throw InvalidPath("path '%s' is not valid", printStorePath(storePath));
+        }
     } catch (...) { return callback.rethrow(); }
 
     auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));

diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
@@ -282,6 +282,16 @@ public:
     void queryPathInfo(const StorePath & path,
         Callback<ref<const ValidPathInfo>> callback) noexcept;
 
+    /**
+     * Version of queryPathInfo() that only queries the local narinfo cache and not
+     * the actual store.
+     *
+     * @return `std::nullopt` if nothing is known about the path in the local narinfo cache.
+     * @return `std::make_optional(nullptr)` if the path is known to not exist.
+     * @return `std::make_optional(validPathInfo)` if the path is known to exist.
+     */
+    std::optional<std::shared_ptr<const ValidPathInfo>> queryPathInfoFromClientCache(const StorePath & path);
+
     /**
      * Query the information about a realisation.
      */