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author | Eelco Dolstra <eelco.dolstra@logicblox.com> | 2016-03-29 14:29:50 +0200 |
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committer | Eelco Dolstra <eelco.dolstra@logicblox.com> | 2016-03-29 16:37:16 +0200 |
commit | 784ee35c80774c5f073b6b8be6ab3d4d7e38e2f1 (patch) | |
tree | 1442cbfe72d75f5cb1dd8d68706220e5821ab374 /src/libutil/thread-pool.hh | |
parent | 0ebe69dc67853e9e2b2b7b22069e766a7cbc057d (diff) |
Add "nix verify-paths" command
Unlike "nix-store --verify-path", this command verifies signatures in
addition to store path contents, is multi-threaded (especially useful
when verifying binary caches), and has a progress indicator.
Example use:
$ nix verify-paths --store https://cache.nixos.org -r $(type -p thunderbird)
...
[17/132 checked] checking ‘/nix/store/rawakphadqrqxr6zri2rmnxh03gqkrl3-autogen-5.18.6’
Diffstat (limited to 'src/libutil/thread-pool.hh')
-rw-r--r-- | src/libutil/thread-pool.hh | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/libutil/thread-pool.hh b/src/libutil/thread-pool.hh new file mode 100644 index 000000000..77641d88b --- /dev/null +++ b/src/libutil/thread-pool.hh @@ -0,0 +1,52 @@ +#pragma once + +#include "sync.hh" +#include "util.hh" + +#include <queue> +#include <functional> +#include <thread> + +namespace nix { + +/* A simple thread pool that executes a queue of work items + (lambdas). */ +class ThreadPool +{ +public: + + ThreadPool(size_t nrThreads = 0); + + // FIXME: use std::packaged_task? + typedef std::function<void()> work_t; + + /* Enqueue a function to be executed by the thread pool. */ + void enqueue(const work_t & t); + + /* Execute work items until the queue is empty. Note that work + items are allowed to add new items to the queue; this is + handled correctly. Queue processing stops prematurely if any + work item throws an exception. This exception is propagated to + the calling thread. If multiple work items throw an exception + concurrently, only one item is propagated; the others are + printed on stderr and otherwise ignored. */ + void process(); + +private: + + size_t nrThreads; + + struct State + { + std::queue<work_t> left; + size_t pending = 0; + std::exception_ptr exception; + }; + + Sync<State> state; + + std::condition_variable wakeup; + +}; + +} |