From 83a6cb804bca0ef1954fb10552666e28f1f9f9c4 Mon Sep 17 00:00:00 2001
From: Max Kellermann <mk@cm4all.com>
Date: Wed, 2 Aug 2023 22:04:00 +0200
Subject: [PATCH] util/IntrusiveHashSet: add template argument `GetKey`
This is a big simplification of all IntrusiveHashSet users: instead of
having to implement multiple overloads of Hash and Equal, the
IntrusiveHashSet class can first extract the effective key from an
item and then pass it to the Hash/Equal functions.
---
src/RemoteTagCache.hxx | 26 ++++++--------------------
src/input/cache/Manager.cxx | 33 +++------------------------------
src/input/cache/Manager.hxx | 25 +++++--------------------
src/util/IntrusiveHashSet.hxx | 30 +++++++++++++++++++-----------
4 files changed, 33 insertions(+), 81 deletions(-)
diff --git a/src/RemoteTagCache.hxx b/src/RemoteTagCache.hxx
index 5295f46d9..96e59c0f2 100644
--- a/src/RemoteTagCache.hxx
+++ b/src/RemoteTagCache.hxx
@@ -52,26 +52,10 @@ class RemoteTagCache final {
void OnRemoteTag(Tag &&tag) noexcept override;
void OnRemoteTagError(std::exception_ptr e) noexcept override;
- struct Hash : std::hash<std::string> {
- using std::hash<std::string>::operator();
-
+ struct GetUri {
[[gnu::pure]]
- std::size_t operator()(const Item &item) const noexcept {
- return std::hash<std::string>::operator()(item.uri);
- }
- };
-
- struct Equal {
- [[gnu::pure]]
- bool operator()(const Item &a,
- const Item &b) const noexcept {
- return a.uri == b.uri;
- }
-
- [[gnu::pure]]
- bool operator()(const std::string &a,
- const Item &b) const noexcept {
- return a == b.uri;
+ std::string_view operator()(const Item &item) const noexcept {
+ return item.uri;
}
};
};
@@ -101,7 +85,9 @@ class RemoteTagCache final {
ItemList invoke_list;
IntrusiveHashSet<Item, 127,
- IntrusiveHashSetOperators<Item::Hash, Item::Equal>,
+ IntrusiveHashSetOperators<std::hash<std::string_view>,
+ std::equal_to<std::string_view>,
+ Item::GetUri>,
IntrusiveHashSetBaseHookTraits<Item>,
true> map;
diff --git a/src/input/cache/Manager.cxx b/src/input/cache/Manager.cxx
index 9ac0ae5d5..9b0356159 100644
--- a/src/input/cache/Manager.cxx
+++ b/src/input/cache/Manager.cxx
@@ -11,37 +11,10 @@
#include <string.h>
-inline std::size_t
-InputCacheManager::ItemHash::operator()(std::string_view uri) const noexcept
+inline std::string_view
+InputCacheManager::ItemGetUri::operator()(const InputCacheItem &item) const noexcept
{
- return std::hash<std::string_view>{}(uri);
-}
-
-inline std::size_t
-InputCacheManager::ItemHash::operator()(const InputCacheItem &item) const noexcept
-{
- return std::hash<std::string_view>{}(item.GetUri());
-}
-
-inline bool
-InputCacheManager::ItemEqual::operator()(const InputCacheItem &a,
- std::string_view b) const noexcept
-{
- return a.GetUri() == b;
-}
-
-inline bool
-InputCacheManager::ItemEqual::operator()(std::string_view a,
- const InputCacheItem &b) const noexcept
-{
- return a == b.GetUri();
-}
-
-inline bool
-InputCacheManager::ItemEqual::operator()(const InputCacheItem &a,
- const InputCacheItem &b) const noexcept
-{
- return a.GetUri() == b.GetUri();
+ return item.GetUri();
}
InputCacheManager::InputCacheManager(const InputCacheConfig &config) noexcept
diff --git a/src/input/cache/Manager.hxx b/src/input/cache/Manager.hxx
index 26cba09af..bf160bb12 100644
--- a/src/input/cache/Manager.hxx
+++ b/src/input/cache/Manager.hxx
@@ -24,32 +24,17 @@ class InputCacheManager {
size_t total_size = 0;
- struct ItemHash {
+ struct ItemGetUri {
[[gnu::pure]]
- std::size_t operator()(std::string_view uri) const noexcept;
-
- [[gnu::pure]]
- std::size_t operator()(const InputCacheItem &item) const noexcept;
- };
-
- struct ItemEqual {
- [[gnu::pure]]
- bool operator()(const InputCacheItem &a,
- std::string_view b) const noexcept;
-
- [[gnu::pure]]
- bool operator()(std::string_view a,
- const InputCacheItem &b) const noexcept;
-
- [[gnu::pure]]
- bool operator()(const InputCacheItem &a,
- const InputCacheItem &b) const noexcept;
+ std::string_view operator()(const InputCacheItem &item) const noexcept;
};
IntrusiveList<InputCacheItem> items_by_time;
IntrusiveHashSet<InputCacheItem, 127,
- IntrusiveHashSetOperators<ItemHash, ItemEqual>> items_by_uri;
+ IntrusiveHashSetOperators<std::hash<std::string_view>,
+ std::equal_to<std::string_view>,
+ ItemGetUri>> items_by_uri;
public:
explicit InputCacheManager(const InputCacheConfig &config) noexcept;
diff --git a/src/util/IntrusiveHashSet.hxx b/src/util/IntrusiveHashSet.hxx
index 5b2520a86..a1a252352 100644
--- a/src/util/IntrusiveHashSet.hxx
+++ b/src/util/IntrusiveHashSet.hxx
@@ -75,7 +75,12 @@ struct IntrusiveHashSetMemberHookTraits {
}
};
-template<typename Hash, typename Equal>
+/**
+ * @param GetKey a function object which extracts the "key" part of an
+ * item
+ */
+template<typename Hash, typename Equal,
+ typename GetKey=std::identity>
struct IntrusiveHashSetOperators {
using hasher = Hash;
using key_equal = Equal;
@@ -85,6 +90,9 @@ struct IntrusiveHashSetOperators {
[[no_unique_address]]
Equal equal;
+
+ [[no_unique_address]]
+ GetKey get_key;
};
/**
@@ -214,7 +222,7 @@ public:
Disposer<value_type> auto disposer) noexcept {
auto &bucket = GetBucket(key);
std::size_t n = bucket.remove_and_dispose_if([this, &key](const auto &item){
- return ops.equal(key, item);
+ return ops.equal(key, ops.get_key(item));
}, disposer);
counter -= n;
return n;
@@ -225,7 +233,7 @@ public:
Disposer<value_type> auto disposer) noexcept {
auto &bucket = GetBucket(key);
std::size_t n = bucket.remove_and_dispose_if([this, &key, &pred](const auto &item){
- return ops.equal(key, item) && pred(item);
+ return ops.equal(key, ops.get_key(item)) && pred(item);
}, disposer);
counter -= n;
return n;
@@ -247,7 +255,7 @@ public:
constexpr std::pair<bucket_iterator, bool> insert_check(const auto &key) noexcept {
auto &bucket = GetBucket(key);
for (auto &i : bucket)
- if (ops.equal(key, i))
+ if (ops.equal(key, ops.get_key(i)))
return {bucket.iterator_to(i), false};
/* bucket.end() is a pointer to the bucket's list
@@ -267,7 +275,7 @@ public:
/* using insert_after() so the new item gets inserted
at the front of the bucket list */
- GetBucket(item).insert_after(bucket, item);
+ GetBucket(ops.get_key(item)).insert_after(bucket, item);
}
/**
@@ -276,12 +284,12 @@ public:
*/
constexpr void insert(reference item) noexcept {
++counter;
- GetBucket(item).push_front(item);
+ GetBucket(ops.get_key(item)).push_front(item);
}
constexpr bucket_iterator erase(bucket_iterator i) noexcept {
--counter;
- return GetBucket(*i).erase(i);
+ return GetBucket(ops.get_key(*i)).erase(i);
}
constexpr bucket_iterator erase_and_dispose(bucket_iterator i,
@@ -295,7 +303,7 @@ public:
constexpr bucket_iterator find(const auto &key) noexcept {
auto &bucket = GetBucket(key);
for (auto &i : bucket)
- if (ops.equal(key, i))
+ if (ops.equal(key, ops.get_key(i)))
return bucket.iterator_to(i);
return end();
@@ -305,7 +313,7 @@ public:
constexpr const_bucket_iterator find(const auto &key) const noexcept {
auto &bucket = GetBucket(key);
for (auto &i : bucket)
- if (ops.equal(key, i))
+ if (ops.equal(key, ops.get_key(i)))
return bucket.iterator_to(i);
return end();
@@ -322,7 +330,7 @@ public:
std::predicate<const_reference> auto pred) noexcept {
auto &bucket = GetBucket(key);
for (auto &i : bucket)
- if (ops.equal(key, i) && pred(i))
+ if (ops.equal(key, ops.get_key(i)) && pred(i))
return bucket.iterator_to(i);
return end();
@@ -349,7 +357,7 @@ public:
auto &bucket = GetBucket(key);
for (auto i = bucket.begin(), e = bucket.end(); i != e;) {
- if (!ops.equal(key, *i))
+ if (!ops.equal(key, ops.get_key(*i)))
++i;
else if (expired_pred(*i))
i = erase_and_dispose(i, disposer);