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tag/Builder: do not acquire tag_pool_lock if TagItem list is empty

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This commit is contained in:
Max Kellermann
2021-08-05 14:30:07 +02:00
parent 96875921b7
commit bde64a13e2
1 changed files with 27 additions and 14 deletions
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41
src/tag/Builder.cxx
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@@ -36,10 +36,12 @@ TagBuilder::TagBuilder(const Tag &other) noexcept
{
items.reserve(other.num_items);
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (unsigned i = 0, n = other.num_items; i != n; ++i)
items.push_back(tag_pool_dup_item(other.items[i]));
const std::size_t n = other.num_items;
if (n > 0) {
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (std::size_t i = 0; i != n; ++i)
items.push_back(tag_pool_dup_item(other.items[i]));
}
}
TagBuilder::TagBuilder(Tag &&other) noexcept
@@ -65,12 +67,15 @@ TagBuilder::operator=(const TagBuilder &other) noexcept
has_playlist = other.has_playlist;
RemoveAll();
items = other.items;
/* increment the tag pool refcounters */
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (auto &i : items)
i = tag_pool_dup_item(i);
if (!other.items.empty()) {
items = other.items;
/* increment the tag pool refcounters */
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (auto &i : items)
i = tag_pool_dup_item(i);
}
return *this;
}
@@ -181,11 +186,14 @@ TagBuilder::Complement(const Tag &other) noexcept
items.reserve(items.size() + other.num_items);
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (unsigned i = 0, n = other.num_items; i != n; ++i) {
TagItem *item = other.items[i];
if (!present[item->type])
items.push_back(tag_pool_dup_item(item));
const std::size_t n = other.num_items;
if (n > 0) {
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (std::size_t i = 0; i != n; ++i) {
TagItem *item = other.items[i];
if (!present[item->type])
items.push_back(tag_pool_dup_item(item));
}
}
}
@@ -245,6 +253,11 @@ TagBuilder::AddEmptyItem(TagType type) noexcept
void
TagBuilder::RemoveAll() noexcept
{
if (items.empty())
/* don't acquire the tag_pool_lock if we're not going
to call tag_pool_put_item() anyway */
return;
{
const std::lock_guard<Mutex> protect(tag_pool_lock);
for (auto i : items)