diff options
Diffstat (limited to 'vendor/github.com/sourcegraph/conc')
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/.golangci.yml | 11 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/LICENSE | 21 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/README.md | 464 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go119.go | 10 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go120.go | 10 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/iter/iter.go | 85 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/iter/map.go | 65 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/panics/panics.go | 102 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/panics/try.go | 11 | ||||
| -rw-r--r-- | vendor/github.com/sourcegraph/conc/waitgroup.go | 52 |
10 files changed, 831 insertions, 0 deletions
diff --git a/vendor/github.com/sourcegraph/conc/.golangci.yml b/vendor/github.com/sourcegraph/conc/.golangci.yml new file mode 100644 index 000000000..ae65a760a --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/.golangci.yml @@ -0,0 +1,11 @@ +linters: + disable-all: true + enable: + - errcheck + - godot + - gosimple + - govet + - ineffassign + - staticcheck + - typecheck + - unused diff --git a/vendor/github.com/sourcegraph/conc/LICENSE b/vendor/github.com/sourcegraph/conc/LICENSE new file mode 100644 index 000000000..1081f4ef4 --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/LICENSE @@ -0,0 +1,21 @@ +MIT License + +Copyright (c) 2023 Sourcegraph + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/vendor/github.com/sourcegraph/conc/README.md b/vendor/github.com/sourcegraph/conc/README.md new file mode 100644 index 000000000..1c87c3c96 --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/README.md @@ -0,0 +1,464 @@ + + +# `conc`: better structured concurrency for go + +[](https://pkg.go.dev/github.com/sourcegraph/conc) +[](https://sourcegraph.com/github.com/sourcegraph/conc) +[](https://goreportcard.com/report/github.com/sourcegraph/conc) +[](https://codecov.io/gh/sourcegraph/conc) +[](https://discord.gg/bvXQXmtRjN) + +`conc` is your toolbelt for structured concurrency in go, making common tasks +easier and safer. + +```sh +go get github.com/sourcegraph/conc +``` + +# At a glance + +- Use [`conc.WaitGroup`](https://pkg.go.dev/github.com/sourcegraph/conc#WaitGroup) if you just want a safer version of `sync.WaitGroup` +- Use [`pool.Pool`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#Pool) if you want a concurrency-limited task runner +- Use [`pool.ResultPool`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#ResultPool) if you want a concurrent task runner that collects task results +- Use [`pool.(Result)?ErrorPool`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#ErrorPool) if your tasks are fallible +- Use [`pool.(Result)?ContextPool`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#ContextPool) if your tasks should be canceled on failure +- Use [`stream.Stream`](https://pkg.go.dev/github.com/sourcegraph/conc/stream#Stream) if you want to process an ordered stream of tasks in parallel with serial callbacks +- Use [`iter.Map`](https://pkg.go.dev/github.com/sourcegraph/conc/iter#Map) if you want to concurrently map a slice +- Use [`iter.ForEach`](https://pkg.go.dev/github.com/sourcegraph/conc/iter#ForEach) if you want to concurrently iterate over a slice +- Use [`panics.Catcher`](https://pkg.go.dev/github.com/sourcegraph/conc/panics#Catcher) if you want to catch panics in your own goroutines + +All pools are created with +[`pool.New()`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#New) +or +[`pool.NewWithResults[T]()`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#NewWithResults), +then configured with methods: + +- [`p.WithMaxGoroutines()`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#Pool.MaxGoroutines) configures the maximum number of goroutines in the pool +- [`p.WithErrors()`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#Pool.WithErrors) configures the pool to run tasks that return errors +- [`p.WithContext(ctx)`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#Pool.WithContext) configures the pool to run tasks that should be canceled on first error +- [`p.WithFirstError()`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#ErrorPool.WithFirstError) configures error pools to only keep the first returned error rather than an aggregated error +- [`p.WithCollectErrored()`](https://pkg.go.dev/github.com/sourcegraph/conc/pool#ResultContextPool.WithCollectErrored) configures result pools to collect results even when the task errored + +# Goals + +The main goals of the package are: +1) Make it harder to leak goroutines +2) Handle panics gracefully +3) Make concurrent code easier to read + +## Goal #1: Make it harder to leak goroutines + +A common pain point when working with goroutines is cleaning them up. It's +really easy to fire off a `go` statement and fail to properly wait for it to +complete. + +`conc` takes the opinionated stance that all concurrency should be scoped. +That is, goroutines should have an owner and that owner should always +ensure that its owned goroutines exit properly. + +In `conc`, the owner of a goroutine is always a `conc.WaitGroup`. Goroutines +are spawned in a `WaitGroup` with `(*WaitGroup).Go()`, and +`(*WaitGroup).Wait()` should always be called before the `WaitGroup` goes out +of scope. + +In some cases, you might want a spawned goroutine to outlast the scope of the +caller. In that case, you could pass a `WaitGroup` into the spawning function. + +```go +func main() { + var wg conc.WaitGroup + defer wg.Wait() + + startTheThing(&wg) +} + +func startTheThing(wg *conc.WaitGroup) { + wg.Go(func() { ... }) +} +``` + +For some more discussion on why scoped concurrency is nice, check out [this +blog +post](https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/). + +## Goal #2: Handle panics gracefully + +A frequent problem with goroutines in long-running applications is handling +panics. A goroutine spawned without a panic handler will crash the whole process +on panic. This is usually undesirable. + +However, if you do add a panic handler to a goroutine, what do you do with the +panic once you catch it? Some options: +1) Ignore it +2) Log it +3) Turn it into an error and return that to the goroutine spawner +4) Propagate the panic to the goroutine spawner + +Ignoring panics is a bad idea since panics usually mean there is actually +something wrong and someone should fix it. + +Just logging panics isn't great either because then there is no indication to the spawner +that something bad happened, and it might just continue on as normal even though your +program is in a really bad state. + +Both (3) and (4) are reasonable options, but both require the goroutine to have +an owner that can actually receive the message that something went wrong. This +is generally not true with a goroutine spawned with `go`, but in the `conc` +package, all goroutines have an owner that must collect the spawned goroutine. +In the conc package, any call to `Wait()` will panic if any of the spawned goroutines +panicked. Additionally, it decorates the panic value with a stacktrace from the child +goroutine so that you don't lose information about what caused the panic. + +Doing this all correctly every time you spawn something with `go` is not +trivial and it requires a lot of boilerplate that makes the important parts of +the code more difficult to read, so `conc` does this for you. + +<table> +<tr> +<th><code>stdlib</code></th> +<th><code>conc</code></th> +</tr> +<tr> +<td> + +```go +type caughtPanicError struct { + val any + stack []byte +} + +func (e *caughtPanicError) Error() string { + return fmt.Sprintf( + "panic: %q\n%s", + e.val, + string(e.stack) + ) +} + +func main() { + done := make(chan error) + go func() { + defer func() { + if v := recover(); v != nil { + done <- &caughtPanicError{ + val: v, + stack: debug.Stack() + } + } else { + done <- nil + } + }() + doSomethingThatMightPanic() + }() + err := <-done + if err != nil { + panic(err) + } +} +``` +</td> +<td> + +```go +func main() { + var wg conc.WaitGroup + wg.Go(doSomethingThatMightPanic) + // panics with a nice stacktrace + wg.Wait() +} +``` +</td> +</tr> +</table> + +## Goal #3: Make concurrent code easier to read + +Doing concurrency correctly is difficult. Doing it in a way that doesn't +obfuscate what the code is actually doing is more difficult. The `conc` package +attempts to make common operations easier by abstracting as much boilerplate +complexity as possible. + +Want to run a set of concurrent tasks with a bounded set of goroutines? Use +`pool.New()`. Want to process an ordered stream of results concurrently, but +still maintain order? Try `stream.New()`. What about a concurrent map over +a slice? Take a peek at `iter.Map()`. + +Browse some examples below for some comparisons with doing these by hand. + +# Examples + +Each of these examples forgoes propagating panics for simplicity. To see +what kind of complexity that would add, check out the "Goal #2" header above. + +Spawn a set of goroutines and waiting for them to finish: + +<table> +<tr> +<th><code>stdlib</code></th> +<th><code>conc</code></th> +</tr> +<tr> +<td> + +```go +func main() { + var wg sync.WaitGroup + for i := 0; i < 10; i++ { + wg.Add(1) + go func() { + defer wg.Done() + // crashes on panic! + doSomething() + }() + } + wg.Wait() +} +``` +</td> +<td> + +```go +func main() { + var wg conc.WaitGroup + for i := 0; i < 10; i++ { + wg.Go(doSomething) + } + wg.Wait() +} +``` +</td> +</tr> +</table> + +Process each element of a stream in a static pool of goroutines: + +<table> +<tr> +<th><code>stdlib</code></th> +<th><code>conc</code></th> +</tr> +<tr> +<td> + +```go +func process(stream chan int) { + var wg sync.WaitGroup + for i := 0; i < 10; i++ { + wg.Add(1) + go func() { + defer wg.Done() + for elem := range stream { + handle(elem) + } + }() + } + wg.Wait() +} +``` +</td> +<td> + +```go +func process(stream chan int) { + p := pool.New().WithMaxGoroutines(10) + for elem := range stream { + elem := elem + p.Go(func() { + handle(elem) + }) + } + p.Wait() +} +``` +</td> +</tr> +</table> + +Process each element of a slice in a static pool of goroutines: + +<table> +<tr> +<th><code>stdlib</code></th> +<th><code>conc</code></th> +</tr> +<tr> +<td> + +```go +func process(values []int) { + feeder := make(chan int, 8) + + var wg sync.WaitGroup + for i := 0; i < 10; i++ { + wg.Add(1) + go func() { + defer wg.Done() + for elem := range feeder { + handle(elem) + } + }() + } + + for _, value := range values { + feeder <- value + } + close(feeder) + wg.Wait() +} +``` +</td> +<td> + +```go +func process(values []int) { + iter.ForEach(values, handle) +} +``` +</td> +</tr> +</table> + +Concurrently map a slice: + +<table> +<tr> +<th><code>stdlib</code></th> +<th><code>conc</code></th> +</tr> +<tr> +<td> + +```go +func concMap( + input []int, + f func(int) int, +) []int { + res := make([]int, len(input)) + var idx atomic.Int64 + + var wg sync.WaitGroup + for i := 0; i < 10; i++ { + wg.Add(1) + go func() { + defer wg.Done() + + for { + i := int(idx.Add(1) - 1) + if i >= len(input) { + return + } + + res[i] = f(input[i]) + } + }() + } + wg.Wait() + return res +} +``` +</td> +<td> + +```go +func concMap( + input []int, + f func(*int) int, +) []int { + return iter.Map(input, f) +} +``` +</td> +</tr> +</table> + +Process an ordered stream concurrently: + + +<table> +<tr> +<th><code>stdlib</code></th> +<th><code>conc</code></th> +</tr> +<tr> +<td> + +```go +func mapStream( + in chan int, + out chan int, + f func(int) int, +) { + tasks := make(chan func()) + taskResults := make(chan chan int) + + // Worker goroutines + var workerWg sync.WaitGroup + for i := 0; i < 10; i++ { + workerWg.Add(1) + go func() { + defer workerWg.Done() + for task := range tasks { + task() + } + }() + } + + // Ordered reader goroutines + var readerWg sync.WaitGroup + readerWg.Add(1) + go func() { + defer readerWg.Done() + for result := range taskResults { + item := <-result + out <- item + } + }() + + // Feed the workers with tasks + for elem := range in { + resultCh := make(chan int, 1) + taskResults <- resultCh + tasks <- func() { + resultCh <- f(elem) + } + } + + // We've exhausted input. + // Wait for everything to finish + close(tasks) + workerWg.Wait() + close(taskResults) + readerWg.Wait() +} +``` +</td> +<td> + +```go +func mapStream( + in chan int, + out chan int, + f func(int) int, +) { + s := stream.New().WithMaxGoroutines(10) + for elem := range in { + elem := elem + s.Go(func() stream.Callback { + res := f(elem) + return func() { out <- res } + }) + } + s.Wait() +} +``` +</td> +</tr> +</table> + +# Status + +This package is currently pre-1.0. There are likely to be minor breaking +changes before a 1.0 release as we stabilize the APIs and tweak defaults. +Please open an issue if you have questions, concerns, or requests that you'd +like addressed before the 1.0 release. Currently, a 1.0 is targeted for +March 2023. diff --git a/vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go119.go b/vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go119.go new file mode 100644 index 000000000..7087e32a8 --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go119.go @@ -0,0 +1,10 @@ +//go:build !go1.20 +// +build !go1.20 + +package multierror + +import "go.uber.org/multierr" + +var ( + Join = multierr.Combine +) diff --git a/vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go120.go b/vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go120.go new file mode 100644 index 000000000..39cff829a --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/internal/multierror/multierror_go120.go @@ -0,0 +1,10 @@ +//go:build go1.20 +// +build go1.20 + +package multierror + +import "errors" + +var ( + Join = errors.Join +) diff --git a/vendor/github.com/sourcegraph/conc/iter/iter.go b/vendor/github.com/sourcegraph/conc/iter/iter.go new file mode 100644 index 000000000..124b4f940 --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/iter/iter.go @@ -0,0 +1,85 @@ +package iter + +import ( + "runtime" + "sync/atomic" + + "github.com/sourcegraph/conc" +) + +// defaultMaxGoroutines returns the default maximum number of +// goroutines to use within this package. +func defaultMaxGoroutines() int { return runtime.GOMAXPROCS(0) } + +// Iterator can be used to configure the behaviour of ForEach +// and ForEachIdx. The zero value is safe to use with reasonable +// defaults. +// +// Iterator is also safe for reuse and concurrent use. +type Iterator[T any] struct { + // MaxGoroutines controls the maximum number of goroutines + // to use on this Iterator's methods. + // + // If unset, MaxGoroutines defaults to runtime.GOMAXPROCS(0). + MaxGoroutines int +} + +// ForEach executes f in parallel over each element in input. +// +// It is safe to mutate the input parameter, which makes it +// possible to map in place. +// +// ForEach always uses at most runtime.GOMAXPROCS goroutines. +// It takes roughly 2µs to start up the goroutines and adds +// an overhead of roughly 50ns per element of input. For +// a configurable goroutine limit, use a custom Iterator. +func ForEach[T any](input []T, f func(*T)) { Iterator[T]{}.ForEach(input, f) } + +// ForEach executes f in parallel over each element in input, +// using up to the Iterator's configured maximum number of +// goroutines. +// +// It is safe to mutate the input parameter, which makes it +// possible to map in place. +// +// It takes roughly 2µs to start up the goroutines and adds +// an overhead of roughly 50ns per element of input. +func (iter Iterator[T]) ForEach(input []T, f func(*T)) { + iter.ForEachIdx(input, func(_ int, t *T) { + f(t) + }) +} + +// ForEachIdx is the same as ForEach except it also provides the +// index of the element to the callback. +func ForEachIdx[T any](input []T, f func(int, *T)) { Iterator[T]{}.ForEachIdx(input, f) } + +// ForEachIdx is the same as ForEach except it also provides the +// index of the element to the callback. +func (iter Iterator[T]) ForEachIdx(input []T, f func(int, *T)) { + if iter.MaxGoroutines == 0 { + // iter is a value receiver and is hence safe to mutate + iter.MaxGoroutines = defaultMaxGoroutines() + } + + numInput := len(input) + if iter.MaxGoroutines > numInput { + // No more concurrent tasks than the number of input items. + iter.MaxGoroutines = numInput + } + + var idx atomic.Int64 + // Create the task outside the loop to avoid extra closure allocations. + task := func() { + i := int(idx.Add(1) - 1) + for ; i < numInput; i = int(idx.Add(1) - 1) { + f(i, &input[i]) + } + } + + var wg conc.WaitGroup + for i := 0; i < iter.MaxGoroutines; i++ { + wg.Go(task) + } + wg.Wait() +} diff --git a/vendor/github.com/sourcegraph/conc/iter/map.go b/vendor/github.com/sourcegraph/conc/iter/map.go new file mode 100644 index 000000000..efbe6bfaf --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/iter/map.go @@ -0,0 +1,65 @@ +package iter + +import ( + "sync" + + "github.com/sourcegraph/conc/internal/multierror" +) + +// Mapper is an Iterator with a result type R. It can be used to configure +// the behaviour of Map and MapErr. The zero value is safe to use with +// reasonable defaults. +// +// Mapper is also safe for reuse and concurrent use. +type Mapper[T, R any] Iterator[T] + +// Map applies f to each element of input, returning the mapped result. +// +// Map always uses at most runtime.GOMAXPROCS goroutines. For a configurable +// goroutine limit, use a custom Mapper. +func Map[T, R any](input []T, f func(*T) R) []R { + return Mapper[T, R]{}.Map(input, f) +} + +// Map applies f to each element of input, returning the mapped result. +// +// Map uses up to the configured Mapper's maximum number of goroutines. +func (m Mapper[T, R]) Map(input []T, f func(*T) R) []R { + res := make([]R, len(input)) + Iterator[T](m).ForEachIdx(input, func(i int, t *T) { + res[i] = f(t) + }) + return res +} + +// MapErr applies f to each element of the input, returning the mapped result +// and a combined error of all returned errors. +// +// Map always uses at most runtime.GOMAXPROCS goroutines. For a configurable +// goroutine limit, use a custom Mapper. +func MapErr[T, R any](input []T, f func(*T) (R, error)) ([]R, error) { + return Mapper[T, R]{}.MapErr(input, f) +} + +// MapErr applies f to each element of the input, returning the mapped result +// and a combined error of all returned errors. +// +// Map uses up to the configured Mapper's maximum number of goroutines. +func (m Mapper[T, R]) MapErr(input []T, f func(*T) (R, error)) ([]R, error) { + var ( + res = make([]R, len(input)) + errMux sync.Mutex + errs error + ) + Iterator[T](m).ForEachIdx(input, func(i int, t *T) { + var err error + res[i], err = f(t) + if err != nil { + errMux.Lock() + // TODO: use stdlib errors once multierrors land in go 1.20 + errs = multierror.Join(errs, err) + errMux.Unlock() + } + }) + return res, errs +} diff --git a/vendor/github.com/sourcegraph/conc/panics/panics.go b/vendor/github.com/sourcegraph/conc/panics/panics.go new file mode 100644 index 000000000..abbed7fa0 --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/panics/panics.go @@ -0,0 +1,102 @@ +package panics + +import ( + "fmt" + "runtime" + "runtime/debug" + "sync/atomic" +) + +// Catcher is used to catch panics. You can execute a function with Try, +// which will catch any spawned panic. Try can be called any number of times, +// from any number of goroutines. Once all calls to Try have completed, you can +// get the value of the first panic (if any) with Recovered(), or you can just +// propagate the panic (re-panic) with Repanic(). +type Catcher struct { + recovered atomic.Pointer[Recovered] +} + +// Try executes f, catching any panic it might spawn. It is safe +// to call from multiple goroutines simultaneously. +func (p *Catcher) Try(f func()) { + defer p.tryRecover() + f() +} + +func (p *Catcher) tryRecover() { + if val := recover(); val != nil { + rp := NewRecovered(1, val) + p.recovered.CompareAndSwap(nil, &rp) + } +} + +// Repanic panics if any calls to Try caught a panic. It will panic with the +// value of the first panic caught, wrapped in a panics.Recovered with caller +// information. +func (p *Catcher) Repanic() { + if val := p.Recovered(); val != nil { + panic(val) + } +} + +// Recovered returns the value of the first panic caught by Try, or nil if +// no calls to Try panicked. +func (p *Catcher) Recovered() *Recovered { + return p.recovered.Load() +} + +// NewRecovered creates a panics.Recovered from a panic value and a collected +// stacktrace. The skip parameter allows the caller to skip stack frames when +// collecting the stacktrace. Calling with a skip of 0 means include the call to +// NewRecovered in the stacktrace. +func NewRecovered(skip int, value any) Recovered { + // 64 frames should be plenty + var callers [64]uintptr + n := runtime.Callers(skip+1, callers[:]) + return Recovered{ + Value: value, + Callers: callers[:n], + Stack: debug.Stack(), + } +} + +// Recovered is a panic that was caught with recover(). +type Recovered struct { + // The original value of the panic. + Value any + // The caller list as returned by runtime.Callers when the panic was + // recovered. Can be used to produce a more detailed stack information with + // runtime.CallersFrames. + Callers []uintptr + // The formatted stacktrace from the goroutine where the panic was recovered. + // Easier to use than Callers. + Stack []byte +} + +// String renders a human-readable formatting of the panic. +func (p *Recovered) String() string { + return fmt.Sprintf("panic: %v\nstacktrace:\n%s\n", p.Value, p.Stack) +} + +// AsError casts the panic into an error implementation. The implementation +// is unwrappable with the cause of the panic, if the panic was provided one. +func (p *Recovered) AsError() error { + if p == nil { + return nil + } + return &ErrRecovered{*p} +} + +// ErrRecovered wraps a panics.Recovered in an error implementation. +type ErrRecovered struct{ Recovered } + +var _ error = (*ErrRecovered)(nil) + +func (p *ErrRecovered) Error() string { return p.String() } + +func (p *ErrRecovered) Unwrap() error { + if err, ok := p.Value.(error); ok { + return err + } + return nil +} diff --git a/vendor/github.com/sourcegraph/conc/panics/try.go b/vendor/github.com/sourcegraph/conc/panics/try.go new file mode 100644 index 000000000..4ded92a1c --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/panics/try.go @@ -0,0 +1,11 @@ +package panics + +// Try executes f, catching and returning any panic it might spawn. +// +// The recovered panic can be propagated with panic(), or handled as a normal error with +// (*panics.Recovered).AsError(). +func Try(f func()) *Recovered { + var c Catcher + c.Try(f) + return c.Recovered() +} diff --git a/vendor/github.com/sourcegraph/conc/waitgroup.go b/vendor/github.com/sourcegraph/conc/waitgroup.go new file mode 100644 index 000000000..47b1bc1a5 --- /dev/null +++ b/vendor/github.com/sourcegraph/conc/waitgroup.go @@ -0,0 +1,52 @@ +package conc + +import ( + "sync" + + "github.com/sourcegraph/conc/panics" +) + +// NewWaitGroup creates a new WaitGroup. +func NewWaitGroup() *WaitGroup { + return &WaitGroup{} +} + +// WaitGroup is the primary building block for scoped concurrency. +// Goroutines can be spawned in the WaitGroup with the Go method, +// and calling Wait() will ensure that each of those goroutines exits +// before continuing. Any panics in a child goroutine will be caught +// and propagated to the caller of Wait(). +// +// The zero value of WaitGroup is usable, just like sync.WaitGroup. +// Also like sync.WaitGroup, it must not be copied after first use. +type WaitGroup struct { + wg sync.WaitGroup + pc panics.Catcher +} + +// Go spawns a new goroutine in the WaitGroup. +func (h *WaitGroup) Go(f func()) { + h.wg.Add(1) + go func() { + defer h.wg.Done() + h.pc.Try(f) + }() +} + +// Wait will block until all goroutines spawned with Go exit and will +// propagate any panics spawned in a child goroutine. +func (h *WaitGroup) Wait() { + h.wg.Wait() + + // Propagate a panic if we caught one from a child goroutine. + h.pc.Repanic() +} + +// WaitAndRecover will block until all goroutines spawned with Go exit and +// will return a *panics.Recovered if one of the child goroutines panics. +func (h *WaitGroup) WaitAndRecover() *panics.Recovered { + h.wg.Wait() + + // Return a recovered panic if we caught one from a child goroutine. + return h.pc.Recovered() +} |