[task scheduler] Move files from build_scheduler/ to task_scheduler/

build_scheduler/go/task_scheduler/cache_wrapper.go

-package task_scheduler
-
-import (
-        "fmt"
-
-        "go.skia.org/infra/build_scheduler/go/db"
-)
-
-// cacheWrapper is an implementation of db.TaskCache which allows insertion of
-// fake Tasks. Use one per task spec.
-type cacheWrapper struct {
-        byCommit map[string]*db.Task
-        byId     map[string]*db.Task
-        c        db.TaskCache
-        known    bool
-}
-
-func newCacheWrapper(c db.TaskCache) *cacheWrapper {
-        return &cacheWrapper{
-                byCommit: map[string]*db.Task{},
-                byId:     map[string]*db.Task{},
-                c:        c,
-                known:    false,
-        }
-}
-
-// See documentation for TaskCache interface.
-func (c *cacheWrapper) GetTask(id string) (*db.Task, error) {
-        if t, ok := c.byId[id]; ok {
-                return t, nil
-        }
-        return c.c.GetTask(id)
-}
-
-// See documentation for TaskCache interface.
-func (c *cacheWrapper) GetTaskForCommit(repo, commit, name string) (*db.Task, error) {
-        if t, ok := c.byCommit[commit]; ok {
-                return t, nil
-        }
-        return c.c.GetTaskForCommit(repo, commit, name)
-}
-
-// See documentation for TaskCache interface.
-func (c *cacheWrapper) GetTasksForCommits(string, []string) (map[string]map[string]*db.Task, error) {
-        return nil, fmt.Errorf("cacheWrapper.GetTasksForCommits not implemented.")
-}
-
-// See documentation for TaskCache interface.
-func (c *cacheWrapper) KnownTaskName(repo, name string) bool {
-        if c.known {
-                return true
-        }
-        return c.c.KnownTaskName(repo, name)
-}
-
-// See documentation for TaskCache interface.
-func (c *cacheWrapper) UnfinishedTasks() ([]*db.Task, error) {
-        return nil, fmt.Errorf("cacheWrapper.UnfinishedTasks not implemented.")
-}
-
-// See documentation for TaskCache interface.
-func (c *cacheWrapper) Update() error {
-        return fmt.Errorf("cacheWrapper.Update not implemented.")
-}
-
-// insert adds a task to the cacheWrapper's fake layer so that it will be
-// included in query results but not actually inserted into the DB.
-func (c *cacheWrapper) insert(t *db.Task) {
-        c.byId[t.Id] = t
-        for _, commit := range t.Commits {
-                c.byCommit[commit] = t
-        }
-        c.known = true
-}