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updating readme and package comments

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This commit is contained in:
Steve Domino
2015-07-07 17:37:08 -06:00
parent f06bf129bb
commit 09d4cba6cf
2 changed files with 98 additions and 29 deletions
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scribble.go
+47 -28
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@@ -5,6 +5,10 @@
// at http://mozilla.org/MPL/2.0/.
//
// scribble is a tiny JSON flat file store. It uses transactions that tell it what
// actions to perform, where it is to store data, and what it is going to write
// that data from, or read the data into. It creates a very simple database
// structure under a specified directory
package scribble
import (
@@ -19,29 +23,29 @@ import (
"github.com/pagodabox/golang-hatchet"
)
//
const Version = "0.0.1"
const Version = "0.1.0"
//
type (
// Driver
// a Driver is what is used to interact with the scribble database. It runs
// transactions, and provides log output
Driver struct {
mutexes map[string]sync.Mutex
dir string
log hatchet.Logger
dir string // the directory where scribble will create the database
log hatchet.Logger // the logger scirbble will log to
}
// Transaction represents
// a Transactions is what is used by a Driver to complete database operations
Transaction struct {
Action string
Collection string
ResourceID string
Container interface{}
Action string // the action for scribble to preform
Collection string // the forlder for scribble to read/write to/from
ResourceID string // the unique ID of the record
Container interface{} // what scribble will marshal from or unmarshal into
}
)
// New
// New creates a new scribble database at the desired directory location, and
// returns a *Driver to then use for interacting with the database
func New(dir string, logger hatchet.Logger) (*Driver, error) {
fmt.Printf("Creating database directory at '%v'...\n", dir)
@@ -57,7 +61,7 @@ func New(dir string, logger hatchet.Logger) (*Driver, error) {
log: logger,
}
//
// create database
if err := mkDir(scribble.dir); err != nil {
return nil, err
}
@@ -66,10 +70,11 @@ func New(dir string, logger hatchet.Logger) (*Driver, error) {
return scribble, nil
}
// Transact
// Transact determins the type of transactions to be run, and calls the appropriate
// method to complete the operation
func (d *Driver) Transact(trans Transaction) error {
//
// determin transaction to be run
switch trans.Action {
case "write":
return d.write(trans)
@@ -86,9 +91,10 @@ func (d *Driver) Transact(trans Transaction) error {
return nil
}
// private
// write
// write locks the database and then proceeds to write the data represented by a
// transaction.Container. It will create a direcotry that represents the collection
// to wich the record belongs (if it doesn't already exist), and write a file
// (named by he transaction.ResourceID) to that directory
func (d *Driver) write(trans Transaction) error {
mutex := d.getOrCreateMutex(trans.Collection)
@@ -103,12 +109,12 @@ func (d *Driver) write(trans Transaction) error {
return err
}
//
// create collection directory
if err := mkDir(dir); err != nil {
return err
}
//
// write marshaled data to a file, named by the resourceID
if err := ioutil.WriteFile(dir+"/"+trans.ResourceID, b, 0666); err != nil {
return err
}
@@ -118,16 +124,20 @@ func (d *Driver) write(trans Transaction) error {
return nil
}
// read
// read does the opposite operation as write. Reading a record from the database
// (named by the transaction.resourceID, found in the transaction.Collection), and
// unmarshaling the data into the transaction.Container
func (d *Driver) read(trans Transaction) error {
dir := d.dir + "/" + trans.Collection
// read record from database
b, err := ioutil.ReadFile(dir + "/" + trans.ResourceID)
if err != nil {
return err
}
// unmarshal data into the transaction.Container
if err := json.Unmarshal(b, trans.Container); err != nil {
return err
}
@@ -135,30 +145,35 @@ func (d *Driver) read(trans Transaction) error {
return nil
}
// readAll
// readAll does the same operation as read, reading all the records in the specified
// transaction.Collection
func (d *Driver) readAll(trans Transaction) error {
dir := d.dir + "/" + trans.Collection
//
// read all the files in the transaction.Collection
files, err := ioutil.ReadDir(dir)
// an error here just means an empty collection so do nothing
if err != nil {
// an error here just means an empty collection so do nothing
}
// the files read from the database
var f []string
// iterate over each of the files, attempting to read the file. If successful
// append the files to the collection of read files
for _, file := range files {
b, err := ioutil.ReadFile(dir + "/" + file.Name())
if err != nil {
return err
}
// append read file
f = append(f, string(b))
}
//
// unmarhsal the read files as a comma delimeted byte array
if err := json.Unmarshal([]byte("["+strings.Join(f, ",")+"]"), trans.Container); err != nil {
return err
}
@@ -166,7 +181,8 @@ func (d *Driver) readAll(trans Transaction) error {
return nil
}
// delete
// delete locks that database and then proceeds to remove the record (specified by
// transaction.ResourceID) from the collection
func (d *Driver) delete(trans Transaction) error {
mutex := d.getOrCreateMutex(trans.Collection)
@@ -174,6 +190,7 @@ func (d *Driver) delete(trans Transaction) error {
dir := d.dir + "/" + trans.Collection
// remove record from database
err := os.Remove(dir + "/" + trans.ResourceID)
if err != nil {
return err
@@ -186,7 +203,8 @@ func (d *Driver) delete(trans Transaction) error {
// helpers
// getOrCreateMutex
// getOrCreateMutex creates a new collection specific mutex any time a collection
// is being modfied to avoid unsafe operations
func (d *Driver) getOrCreateMutex(collection string) sync.Mutex {
c, ok := d.mutexes[collection]
@@ -200,7 +218,8 @@ func (d *Driver) getOrCreateMutex(collection string) sync.Mutex {
return c
}
// mkDir
// mkDir is a simple wrapper that attempts to make a directory at a specified
// location
func mkDir(d string) error {
//