From 784ee35c80774c5f073b6b8be6ab3d4d7e38e2f1 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 29 Mar 2016 14:29:50 +0200
Subject: Add "nix verify-paths" command
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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’
---
 src/libutil/thread-pool.cc | 81 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 src/libutil/thread-pool.cc

(limited to 'src/libutil/thread-pool.cc')

diff --git a/src/libutil/thread-pool.cc b/src/libutil/thread-pool.cc
new file mode 100644
index 000000000000..819aed748340
--- /dev/null
+++ b/src/libutil/thread-pool.cc
@@ -0,0 +1,81 @@
+#include "thread-pool.hh"
+
+namespace nix {
+
+ThreadPool::ThreadPool(size_t _nrThreads)
+    : nrThreads(_nrThreads)
+{
+    if (!nrThreads) {
+        nrThreads = std::thread::hardware_concurrency();
+        if (!nrThreads) nrThreads = 1;
+    }
+}
+
+void ThreadPool::enqueue(const work_t & t)
+{
+    auto state_(state.lock());
+    state_->left.push(t);
+    wakeup.notify_one();
+}
+
+void ThreadPool::process()
+{
+    printMsg(lvlDebug, format("starting pool of %d threads") % nrThreads);
+
+    std::vector<std::thread> workers;
+
+    for (size_t n = 0; n < nrThreads; n++)
+        workers.push_back(std::thread([&]() {
+            bool first = true;
+
+            while (true) {
+                work_t work;
+                {
+                    auto state_(state.lock());
+                    if (state_->exception) return;
+                    if (!first) {
+                        assert(state_->pending);
+                        state_->pending--;
+                    }
+                    first = false;
+                    while (state_->left.empty()) {
+                        if (!state_->pending) {
+                            wakeup.notify_all();
+                            return;
+                        }
+                        if (state_->exception) return;
+                        state_.wait(wakeup);
+                    }
+                    work = state_->left.front();
+                    state_->left.pop();
+                    state_->pending++;
+                }
+
+                try {
+                    work();
+                } catch (std::exception & e) {
+                    auto state_(state.lock());
+                    if (state_->exception)
+                        printMsg(lvlError, format("error: %s") % e.what());
+                    else {
+                        state_->exception = std::current_exception();
+                        wakeup.notify_all();
+                    }
+                }
+            }
+
+        }));
+
+    for (auto & thr : workers)
+        thr.join();
+
+    {
+        auto state_(state.lock());
+        if (state_->exception)
+            std::rethrow_exception(state_->exception);
+    }
+}
+
+}
+
+
-- 
cgit 1.4.1