X-Git-Url: https://git.josue.xyz/?a=blobdiff_plain;f=.config%2Fcoc%2Fextensions%2Fcoc-go-data%2Ftools%2Fpkg%2Fmod%2Fmvdan.cc%2Fgofumpt%40v0.0.0-20200802201014-ab5a8192947d%2Fgofumports%2Finternal%2Fimports%2Fmod_cache.go;fp=.config%2Fcoc%2Fextensions%2Fcoc-go-data%2Ftools%2Fpkg%2Fmod%2Fmvdan.cc%2Fgofumpt%40v0.0.0-20200802201014-ab5a8192947d%2Fgofumports%2Finternal%2Fimports%2Fmod_cache.go;h=bd3fb53c1987f7c2835f0b512cbb692143e62689;hb=4d07c77cf4d78cab8639e13ddc3c22495e585b0b;hp=0000000000000000000000000000000000000000;hpb=b3950616b54221c40a7dab9099bda675007e5b6e;p=dotfiles%2F.git diff --git a/.config/coc/extensions/coc-go-data/tools/pkg/mod/mvdan.cc/gofumpt@v0.0.0-20200802201014-ab5a8192947d/gofumports/internal/imports/mod_cache.go b/.config/coc/extensions/coc-go-data/tools/pkg/mod/mvdan.cc/gofumpt@v0.0.0-20200802201014-ab5a8192947d/gofumports/internal/imports/mod_cache.go new file mode 100644 index 00000000..bd3fb53c --- /dev/null +++ b/.config/coc/extensions/coc-go-data/tools/pkg/mod/mvdan.cc/gofumpt@v0.0.0-20200802201014-ab5a8192947d/gofumports/internal/imports/mod_cache.go @@ -0,0 +1,232 @@ +package imports + +import ( + "context" + "fmt" + "sync" + + "mvdan.cc/gofumpt/gofumports/internal/gopathwalk" +) + +// To find packages to import, the resolver needs to know about all of the +// the packages that could be imported. This includes packages that are +// already in modules that are in (1) the current module, (2) replace targets, +// and (3) packages in the module cache. Packages in (1) and (2) may change over +// time, as the client may edit the current module and locally replaced modules. +// The module cache (which includes all of the packages in (3)) can only +// ever be added to. +// +// The resolver can thus save state about packages in the module cache +// and guarantee that this will not change over time. To obtain information +// about new modules added to the module cache, the module cache should be +// rescanned. +// +// It is OK to serve information about modules that have been deleted, +// as they do still exist. +// TODO(suzmue): can we share information with the caller about +// what module needs to be downloaded to import this package? + +type directoryPackageStatus int + +const ( + _ directoryPackageStatus = iota + directoryScanned + nameLoaded + exportsLoaded +) + +type directoryPackageInfo struct { + // status indicates the extent to which this struct has been filled in. + status directoryPackageStatus + // err is non-nil when there was an error trying to reach status. + err error + + // Set when status >= directoryScanned. + + // dir is the absolute directory of this package. + dir string + rootType gopathwalk.RootType + // nonCanonicalImportPath is the package's expected import path. It may + // not actually be importable at that path. + nonCanonicalImportPath string + + // Module-related information. + moduleDir string // The directory that is the module root of this dir. + moduleName string // The module name that contains this dir. + + // Set when status >= nameLoaded. + + packageName string // the package name, as declared in the source. + + // Set when status >= exportsLoaded. + + exports []string +} + +// reachedStatus returns true when info has a status at least target and any error associated with +// an attempt to reach target. +func (info *directoryPackageInfo) reachedStatus(target directoryPackageStatus) (bool, error) { + if info.err == nil { + return info.status >= target, nil + } + if info.status == target { + return true, info.err + } + return true, nil +} + +// dirInfoCache is a concurrency safe map for storing information about +// directories that may contain packages. +// +// The information in this cache is built incrementally. Entries are initialized in scan. +// No new keys should be added in any other functions, as all directories containing +// packages are identified in scan. +// +// Other functions, including loadExports and findPackage, may update entries in this cache +// as they discover new things about the directory. +// +// The information in the cache is not expected to change for the cache's +// lifetime, so there is no protection against competing writes. Users should +// take care not to hold the cache across changes to the underlying files. +// +// TODO(suzmue): consider other concurrency strategies and data structures (RWLocks, sync.Map, etc) +type dirInfoCache struct { + mu sync.Mutex + // dirs stores information about packages in directories, keyed by absolute path. + dirs map[string]*directoryPackageInfo + listeners map[*int]cacheListener +} + +type cacheListener func(directoryPackageInfo) + +// ScanAndListen calls listener on all the items in the cache, and on anything +// newly added. The returned stop function waits for all in-flight callbacks to +// finish and blocks new ones. +func (d *dirInfoCache) ScanAndListen(ctx context.Context, listener cacheListener) func() { + ctx, cancel := context.WithCancel(ctx) + + // Flushing out all the callbacks is tricky without knowing how many there + // are going to be. Setting an arbitrary limit makes it much easier. + const maxInFlight = 10 + sema := make(chan struct{}, maxInFlight) + for i := 0; i < maxInFlight; i++ { + sema <- struct{}{} + } + + cookie := new(int) // A unique ID we can use for the listener. + + // We can't hold mu while calling the listener. + d.mu.Lock() + var keys []string + for key := range d.dirs { + keys = append(keys, key) + } + d.listeners[cookie] = func(info directoryPackageInfo) { + select { + case <-ctx.Done(): + return + case <-sema: + } + listener(info) + sema <- struct{}{} + } + d.mu.Unlock() + + stop := func() { + cancel() + d.mu.Lock() + delete(d.listeners, cookie) + d.mu.Unlock() + for i := 0; i < maxInFlight; i++ { + <-sema + } + } + + // Process the pre-existing keys. + for _, k := range keys { + select { + case <-ctx.Done(): + return stop + default: + } + if v, ok := d.Load(k); ok { + listener(v) + } + } + + return stop +} + +// Store stores the package info for dir. +func (d *dirInfoCache) Store(dir string, info directoryPackageInfo) { + d.mu.Lock() + _, old := d.dirs[dir] + d.dirs[dir] = &info + var listeners []cacheListener + for _, l := range d.listeners { + listeners = append(listeners, l) + } + d.mu.Unlock() + + if !old { + for _, l := range listeners { + l(info) + } + } +} + +// Load returns a copy of the directoryPackageInfo for absolute directory dir. +func (d *dirInfoCache) Load(dir string) (directoryPackageInfo, bool) { + d.mu.Lock() + defer d.mu.Unlock() + info, ok := d.dirs[dir] + if !ok { + return directoryPackageInfo{}, false + } + return *info, true +} + +// Keys returns the keys currently present in d. +func (d *dirInfoCache) Keys() (keys []string) { + d.mu.Lock() + defer d.mu.Unlock() + for key := range d.dirs { + keys = append(keys, key) + } + return keys +} + +func (d *dirInfoCache) CachePackageName(info directoryPackageInfo) (string, error) { + if loaded, err := info.reachedStatus(nameLoaded); loaded { + return info.packageName, err + } + if scanned, err := info.reachedStatus(directoryScanned); !scanned || err != nil { + return "", fmt.Errorf("cannot read package name, scan error: %v", err) + } + info.packageName, info.err = packageDirToName(info.dir) + info.status = nameLoaded + d.Store(info.dir, info) + return info.packageName, info.err +} + +func (d *dirInfoCache) CacheExports(ctx context.Context, env *ProcessEnv, info directoryPackageInfo) (string, []string, error) { + if reached, _ := info.reachedStatus(exportsLoaded); reached { + return info.packageName, info.exports, info.err + } + if reached, err := info.reachedStatus(nameLoaded); reached && err != nil { + return "", nil, err + } + info.packageName, info.exports, info.err = loadExportsFromFiles(ctx, env, info.dir, false) + if info.err == context.Canceled || info.err == context.DeadlineExceeded { + return info.packageName, info.exports, info.err + } + // The cache structure wants things to proceed linearly. We can skip a + // step here, but only if we succeed. + if info.status == nameLoaded || info.err == nil { + info.status = exportsLoaded + } else { + info.status = nameLoaded + } + d.Store(info.dir, info) + return info.packageName, info.exports, info.err +}