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

build_scheduler/go/db/modified_tasks.go

Index: build_scheduler/go/db/modified_tasks.go
diff --git a/build_scheduler/go/db/modified_tasks.go b/build_scheduler/go/db/modified_tasks.go
deleted file mode 100644
index b76dd9221e30485eb1c04bc3cd896bc485310d21..0000000000000000000000000000000000000000
--- a/build_scheduler/go/db/modified_tasks.go
+++ /dev/null
@@ -1,128 +0,0 @@
-package db
-
-import (
-	"bytes"
-	"encoding/gob"
-	"sort"
-	"sync"
-	"time"
-
-	"github.com/satori/go.uuid"
-	"github.com/skia-dev/glog"
-)
-
-// ModifiedTasks allows subscribers to keep track of Tasks that have been
-// modified. It implements StartTrackingModifiedTasks and GetModifiedTasks from
-// the DB interface.
-type ModifiedTasks struct {
-	// map[subscriber_id][task_id]task_gob
-	tasks map[string]map[string][]byte
-	// After the expiration time, subscribers are automatically removed.
-	expiration map[string]time.Time
-	// Protects tasks and expiration.
-	mtx sync.RWMutex
-}
-
-// See docs for DB interface.
-func (m *ModifiedTasks) GetModifiedTasks(id string) ([]*Task, error) {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	if _, ok := m.expiration[id]; !ok {
-		return nil, ErrUnknownId
-	}
-	d := TaskDecoder{}
-	for _, g := range m.tasks[id] {
-		if !d.Process(g) {
-			break
-		}
-	}
-	rv, err := d.Result()
-	if err != nil {
-		return nil, err
-	}
-	m.expiration[id] = time.Now().Add(MODIFIED_TASKS_TIMEOUT)
-	delete(m.tasks, id)
-	sort.Sort(TaskSlice(rv))
-	return rv, nil
-}
-
-// clearExpiredSubscribers periodically deletes data about any subscribers that
-// haven't been seen within MODIFIED_TASKS_TIMEOUT. Must be called as a
-// goroutine. Returns when there are no remaining subscribers.
-func (m *ModifiedTasks) clearExpiredSubscribers() {
-	ticker := time.NewTicker(time.Minute)
-	for _ = range ticker.C {
-		m.mtx.Lock()
-		for id, t := range m.expiration {
-			if time.Now().After(t) {
-				glog.Warningf("Deleting expired subscriber with id %s; expiration time %s.", id, t)
-				delete(m.tasks, id)
-				delete(m.expiration, id)
-			}
-		}
-		anyLeft := len(m.expiration) > 0
-		if !anyLeft {
-			m.tasks = nil
-			m.expiration = nil
-		}
-		m.mtx.Unlock()
-		if !anyLeft {
-			break
-		}
-	}
-	ticker.Stop()
-}
-
-// TrackModifiedTask indicates the given Task should be returned from the next
-// call to GetModifiedTasks from each subscriber.
-func (m *ModifiedTasks) TrackModifiedTask(t *Task) {
-	var buf bytes.Buffer
-	if err := gob.NewEncoder(&buf).Encode(t); err != nil {
-		glog.Fatal(err)
-	}
-	m.TrackModifiedTasksGOB(map[string][]byte{t.Id: buf.Bytes()})
-}
-
-// TrackModifiedTasksGOB is a batch, GOB version of TrackModifiedTask. Given a
-// map from Task.Id to GOB-encoded task, it is equivalent to GOB-decoding each
-// value of gobs as a Task and calling TrackModifiedTask on each one. Values of
-// gobs must not be modified after this call.
-func (m *ModifiedTasks) TrackModifiedTasksGOB(gobs map[string][]byte) {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	for subId, _ := range m.expiration {
-		sub, ok := m.tasks[subId]
-		if !ok {
-			sub = make(map[string][]byte, len(gobs))
-			m.tasks[subId] = sub
-		}
-		for taskId, gob := range gobs {
-			sub[taskId] = gob
-		}
-	}
-}
-
-// See docs for DB interface.
-func (m *ModifiedTasks) StartTrackingModifiedTasks() (string, error) {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	if m.expiration == nil {
-		// Initialize the data structure and start expiration goroutine.
-		m.tasks = map[string]map[string][]byte{}
-		m.expiration = map[string]time.Time{}
-		go m.clearExpiredSubscribers()
-	} else if len(m.expiration) >= MAX_MODIFIED_TASKS_USERS {
-		return "", ErrTooManyUsers
-	}
-	id := uuid.NewV5(uuid.NewV1(), uuid.NewV4().String()).String()
-	m.expiration[id] = time.Now().Add(MODIFIED_TASKS_TIMEOUT)
-	return id, nil
-}
-
-// See docs for DB interface.
-func (m *ModifiedTasks) StopTrackingModifiedTasks(id string) {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	delete(m.tasks, id)
-	delete(m.expiration, id)
-}