diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 12:36:04 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 12:36:04 +0000 |
commit | b09c6d56832eb1718c07d74abf3bc6ae3fe4e030 (patch) | |
tree | d2caec2610d4ea887803ec9e9c3cd77136c448ba /dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup | |
parent | Initial commit. (diff) | |
download | icingadb-upstream.tar.xz icingadb-upstream.zip |
Adding upstream version 1.1.0.upstream/1.1.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
3 files changed, 343 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go b/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go new file mode 100644 index 0000000..9857fe5 --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go @@ -0,0 +1,66 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package errgroup provides synchronization, error propagation, and Context +// cancelation for groups of goroutines working on subtasks of a common task. +package errgroup + +import ( + "context" + "sync" +) + +// A Group is a collection of goroutines working on subtasks that are part of +// the same overall task. +// +// A zero Group is valid and does not cancel on error. +type Group struct { + cancel func() + + wg sync.WaitGroup + + errOnce sync.Once + err error +} + +// WithContext returns a new Group and an associated Context derived from ctx. +// +// The derived Context is canceled the first time a function passed to Go +// returns a non-nil error or the first time Wait returns, whichever occurs +// first. +func WithContext(ctx context.Context) (*Group, context.Context) { + ctx, cancel := context.WithCancel(ctx) + return &Group{cancel: cancel}, ctx +} + +// Wait blocks until all function calls from the Go method have returned, then +// returns the first non-nil error (if any) from them. +func (g *Group) Wait() error { + g.wg.Wait() + if g.cancel != nil { + g.cancel() + } + return g.err +} + +// Go calls the given function in a new goroutine. +// +// The first call to return a non-nil error cancels the group; its error will be +// returned by Wait. +func (g *Group) Go(f func() error) { + g.wg.Add(1) + + go func() { + defer g.wg.Done() + + if err := f(); err != nil { + g.errOnce.Do(func() { + g.err = err + if g.cancel != nil { + g.cancel() + } + }) + } + }() +} diff --git a/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup_example_md5all_test.go b/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup_example_md5all_test.go new file mode 100644 index 0000000..739b336 --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup_example_md5all_test.go @@ -0,0 +1,101 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package errgroup_test + +import ( + "context" + "crypto/md5" + "fmt" + "io/ioutil" + "log" + "os" + "path/filepath" + + "golang.org/x/sync/errgroup" +) + +// Pipeline demonstrates the use of a Group to implement a multi-stage +// pipeline: a version of the MD5All function with bounded parallelism from +// https://blog.golang.org/pipelines. +func ExampleGroup_pipeline() { + m, err := MD5All(context.Background(), ".") + if err != nil { + log.Fatal(err) + } + + for k, sum := range m { + fmt.Printf("%s:\t%x\n", k, sum) + } +} + +type result struct { + path string + sum [md5.Size]byte +} + +// MD5All reads all the files in the file tree rooted at root and returns a map +// from file path to the MD5 sum of the file's contents. If the directory walk +// fails or any read operation fails, MD5All returns an error. +func MD5All(ctx context.Context, root string) (map[string][md5.Size]byte, error) { + // ctx is canceled when g.Wait() returns. When this version of MD5All returns + // - even in case of error! - we know that all of the goroutines have finished + // and the memory they were using can be garbage-collected. + g, ctx := errgroup.WithContext(ctx) + paths := make(chan string) + + g.Go(func() error { + defer close(paths) + return filepath.Walk(root, func(path string, info os.FileInfo, err error) error { + if err != nil { + return err + } + if !info.Mode().IsRegular() { + return nil + } + select { + case paths <- path: + case <-ctx.Done(): + return ctx.Err() + } + return nil + }) + }) + + // Start a fixed number of goroutines to read and digest files. + c := make(chan result) + const numDigesters = 20 + for i := 0; i < numDigesters; i++ { + g.Go(func() error { + for path := range paths { + data, err := ioutil.ReadFile(path) + if err != nil { + return err + } + select { + case c <- result{path, md5.Sum(data)}: + case <-ctx.Done(): + return ctx.Err() + } + } + return nil + }) + } + go func() { + g.Wait() + close(c) + }() + + m := make(map[string][md5.Size]byte) + for r := range c { + m[r.path] = r.sum + } + // Check whether any of the goroutines failed. Since g is accumulating the + // errors, we don't need to send them (or check for them) in the individual + // results sent on the channel. + if err := g.Wait(); err != nil { + return nil, err + } + return m, nil +} diff --git a/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup_test.go b/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup_test.go new file mode 100644 index 0000000..5a0b9cb --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup_test.go @@ -0,0 +1,176 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package errgroup_test + +import ( + "context" + "errors" + "fmt" + "net/http" + "os" + "testing" + + "golang.org/x/sync/errgroup" +) + +var ( + Web = fakeSearch("web") + Image = fakeSearch("image") + Video = fakeSearch("video") +) + +type Result string +type Search func(ctx context.Context, query string) (Result, error) + +func fakeSearch(kind string) Search { + return func(_ context.Context, query string) (Result, error) { + return Result(fmt.Sprintf("%s result for %q", kind, query)), nil + } +} + +// JustErrors illustrates the use of a Group in place of a sync.WaitGroup to +// simplify goroutine counting and error handling. This example is derived from +// the sync.WaitGroup example at https://golang.org/pkg/sync/#example_WaitGroup. +func ExampleGroup_justErrors() { + g := new(errgroup.Group) + var urls = []string{ + "http://www.golang.org/", + "http://www.google.com/", + "http://www.somestupidname.com/", + } + for _, url := range urls { + // Launch a goroutine to fetch the URL. + url := url // https://golang.org/doc/faq#closures_and_goroutines + g.Go(func() error { + // Fetch the URL. + resp, err := http.Get(url) + if err == nil { + resp.Body.Close() + } + return err + }) + } + // Wait for all HTTP fetches to complete. + if err := g.Wait(); err == nil { + fmt.Println("Successfully fetched all URLs.") + } +} + +// Parallel illustrates the use of a Group for synchronizing a simple parallel +// task: the "Google Search 2.0" function from +// https://talks.golang.org/2012/concurrency.slide#46, augmented with a Context +// and error-handling. +func ExampleGroup_parallel() { + Google := func(ctx context.Context, query string) ([]Result, error) { + g, ctx := errgroup.WithContext(ctx) + + searches := []Search{Web, Image, Video} + results := make([]Result, len(searches)) + for i, search := range searches { + i, search := i, search // https://golang.org/doc/faq#closures_and_goroutines + g.Go(func() error { + result, err := search(ctx, query) + if err == nil { + results[i] = result + } + return err + }) + } + if err := g.Wait(); err != nil { + return nil, err + } + return results, nil + } + + results, err := Google(context.Background(), "golang") + if err != nil { + fmt.Fprintln(os.Stderr, err) + return + } + for _, result := range results { + fmt.Println(result) + } + + // Output: + // web result for "golang" + // image result for "golang" + // video result for "golang" +} + +func TestZeroGroup(t *testing.T) { + err1 := errors.New("errgroup_test: 1") + err2 := errors.New("errgroup_test: 2") + + cases := []struct { + errs []error + }{ + {errs: []error{}}, + {errs: []error{nil}}, + {errs: []error{err1}}, + {errs: []error{err1, nil}}, + {errs: []error{err1, nil, err2}}, + } + + for _, tc := range cases { + g := new(errgroup.Group) + + var firstErr error + for i, err := range tc.errs { + err := err + g.Go(func() error { return err }) + + if firstErr == nil && err != nil { + firstErr = err + } + + if gErr := g.Wait(); gErr != firstErr { + t.Errorf("after %T.Go(func() error { return err }) for err in %v\n"+ + "g.Wait() = %v; want %v", + g, tc.errs[:i+1], err, firstErr) + } + } + } +} + +func TestWithContext(t *testing.T) { + errDoom := errors.New("group_test: doomed") + + cases := []struct { + errs []error + want error + }{ + {want: nil}, + {errs: []error{nil}, want: nil}, + {errs: []error{errDoom}, want: errDoom}, + {errs: []error{errDoom, nil}, want: errDoom}, + } + + for _, tc := range cases { + g, ctx := errgroup.WithContext(context.Background()) + + for _, err := range tc.errs { + err := err + g.Go(func() error { return err }) + } + + if err := g.Wait(); err != tc.want { + t.Errorf("after %T.Go(func() error { return err }) for err in %v\n"+ + "g.Wait() = %v; want %v", + g, tc.errs, err, tc.want) + } + + canceled := false + select { + case <-ctx.Done(): + canceled = true + default: + } + if !canceled { + t.Errorf("after %T.Go(func() error { return err }) for err in %v\n"+ + "ctx.Done() was not closed", + g, tc.errs) + } + } +} |