Fix Locale.findPO to support language code simplification on LC_MESSAGES dir.

added support for .po files stored in a LC_MESSAGES subdir

README.md

@@ -4,20 +4,21 @@
 
 GNU gettext utilities for Go. 
 
-**Version: 0.9.0**
+Version: [1.0.1](https://github.com/leonelquinteros/gotext/releases/tag/v1.0.1)
 
 
-#Features
+# Features
 
 - Implements GNU gettext support in native Go.
-- Safe for concurrent use accross multiple goroutines. 
+- Complete support for [PO files](https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html).
+- Support for [pluralization rules](https://www.gnu.org/software/gettext/manual/html_node/Plural-forms.html).
+- Support for [message context](https://www.gnu.org/software/gettext/manual/html_node/Contexts.html).
+- Support for variables inside translation strings using Go's [fmt package syntax](https://golang.org/pkg/fmt/).
+- Thread-safe: This package is safe for concurrent use across multiple goroutines. 
 - It works with UTF-8 encoding as it's the default for Go language.
-- Unit tests available 
-- Language codes are automatically simplified from the form "en_UK" to "en" if the formed isn't available.
+- Unit tests available.
+- Language codes are automatically simplified from the form `en_UK` to `en` if the first isn't available.
 - Ready to use inside Go templates.
-- Support for pluralization rules.
-- Support for variables inside translation strings using Go's [fmt package syntax](https://golang.org/pkg/fmt/)
-
 
 
 # Installation 
@@ -43,30 +44,34 @@ Refer to the Godoc package documentation at (https://godoc.org/github.com/leonel
 
 # Locales directories structure
 
-The package will asume a directories structure starting with a base path that will be provided to the package configuration 
+The package will assume a directories structure starting with a base path that will be provided to the package configuration 
 or to object constructors depending on the use, but either will use the same convention to lookup inside the base path. 
 
 Inside the base directory where will be the language directories named using the language and country 2-letter codes (en_US, es_AR, ...). 
 All package functions can lookup after the simplified version for each language in case the full code isn't present but the more general language code exists. 
-So if the language set is "en_UK", but there is no directory named after that code and there is a directory named "en", 
+So if the language set is `en_UK`, but there is no directory named after that code and there is a directory named `en`, 
 all package functions will be able to resolve this generalization and provide translations for the more general library.  
 
 The language codes are assumed to be [ISO 639-1](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes) codes (2-letter codes). 
 That said, most functions will work with any coding standard as long the directory name matches the language code set on the configuration.
 
-A normal library directory structure may look like: 
+Then, there can be a `LC_MESSAGES` containing all PO files or the PO files themselves.  
+A library directory structure can look like: 
 
 ```
 /path/to/locales
 /path/to/locales/en_US
-/path/to/locales/en_US/default.po
-/path/to/locales/en_US/extras.po
+/path/to/locales/en_US/LC_MESSAGES
+/path/to/locales/en_US/LC_MESSAGES/default.po
+/path/to/locales/en_US/LC_MESSAGES/extras.po
 /path/to/locales/en_UK
-/path/to/locales/en_UK/default.po
-/path/to/locales/en_UK/extras.po
+/path/to/locales/en_UK/LC_MESSAGES
+/path/to/locales/en_UK/LC_MESSAGES/default.po
+/path/to/locales/en_UK/LC_MESSAGES/extras.po
 /path/to/locales/en_AU
-/path/to/locales/en_AU/default.po
-/path/to/locales/en_AU/extras.po
+/path/to/locales/en_AU/LC_MESSAGES
+/path/to/locales/en_AU/LC_MESSAGES/default.po
+/path/to/locales/en_AU/LC_MESSAGES/extras.po
 /path/to/locales/es
 /path/to/locales/es/default.po
 /path/to/locales/es/extras.po
@@ -84,9 +89,9 @@ And so on...
 
 # About translation function names
 
-The standard GNU gettext defines helper functions that maps to the gettext() function and it's widely adopted by most implementations. 
+The standard GNU gettext defines helper functions that maps to the `gettext()` function and it's widely adopted by most implementations. 
 
-The basic translation function is usually _() in the form: 
+The basic translation function is usually `_()` in the form: 
 
 ```
 _("Translate this")
@@ -109,8 +114,8 @@ func _(str string, vars ...interface{}) string {
 
 This is valid and can be used within a package.
 
-In normal conditions the Go compiler will optimize the calls to _() by replacing its content in place of the function call to reduce the function calling overhead. 
-This is a normal Go compiler behaviour.  
+In normal conditions the Go compiler will optimize the calls to `_()` by replacing its content in place of the function call to reduce the function calling overhead. 
+This is a normal Go compiler behavior.  
 
 
 
@@ -185,7 +190,7 @@ func main() {
 ```
 
 This is also helpful for using inside templates (from the "text/template" package), where you can pass the Locale object to the template.
-If you set the Locale object as "Loc" in the template, then the templace code would look like: 
+If you set the Locale object as "Loc" in the template, then the template code would look like: 
 
 ```
 {{ .Loc.Get "Translate this" }}

gotext.go

@@ -1,8 +1,6 @@
 /*
 Package gotext implements GNU gettext utilities.
 
-Version 0.9.0 (stable)
-
 For quick/simple translations you can use the package level functions directly.
 
     import "github.com/leonelquinteros/gotext"
@@ -124,3 +122,32 @@ func GetND(dom, str, plural string, n int, vars ...interface{}) string {
 	// Return translation
 	return storage.GetND(dom, str, plural, n, vars...)
 }
+
+// GetC uses the default domain globally set to return the corresponding translation of the given string in the given context.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func GetC(str, ctx string, vars ...interface{}) string {
+	return GetDC(domain, str, ctx, vars...)
+}
+
+// GetNC retrieves the (N)th plural form translation for the given string in the given context in the "default" domain.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
+	return GetNDC("default", str, plural, n, ctx, vars...)
+}
+
+// GetDC returns the corresponding translation in the given domain for the given string in the given context.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func GetDC(dom, str, ctx string, vars ...interface{}) string {
+	return GetNDC(dom, str, str, 0, ctx, vars...)
+}
+
+// GetNDC retrieves the (N)th plural form translation in the given domain for a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func GetNDC(dom, str, plural string, n int, ctx string, vars ...interface{}) string {
+	// Try to load default package Locale storage
+	loadStorage(false)
+
+	// Return translation
+	return storage.GetNDC(dom, str, plural, n, ctx, vars...)
+}

gotext_test.go

@@ -6,6 +6,29 @@ import (
 	"testing"
 )
 
+func TestGettersSetters(t *testing.T) {
+	SetDomain("test")
+	dom := GetDomain()
+
+	if dom != "test" {
+		t.Errorf("Expected GetDomain to return 'test', but got '%s'", dom)
+	}
+
+	SetLibrary("/tmp/test")
+	lib := GetLibrary()
+
+	if lib != "/tmp/test" {
+		t.Errorf("Expected GetLibrary to return '/tmp/test', but got '%s'", lib)
+	}
+
+	SetLanguage("es")
+	lang := GetLanguage()
+
+	if lang != "es" {
+		t.Errorf("Expected GetLanguage to return 'es', but got '%s'", lang)
+	}
+}
+
 func TestPackageFunctions(t *testing.T) {
 	// Set PO content
 	str := `# Some comment
@@ -16,6 +39,108 @@ msgstr "Translated text"
 msgid "Another string"
 msgstr ""
 
+msgid "One with var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular: %s"
+msgstr[1] "This one is the plural: %s"
+msgstr[2] "And this is the second plural form: %s"
+
+msgid "This one has invalid syntax translations"
+msgid_plural "Plural index"
+msgstr[abc] "Wrong index"
+msgstr[1 "Forgot to close brackets"
+msgstr[0] "Badly formatted string'
+
+msgid "Invalid formatted id[] with no translations
+
+msgctxt "Ctx"
+msgid "One with var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular in a Ctx context: %s"
+msgstr[1] "This one is the plural in a Ctx context: %s"
+
+msgid "Some random"
+msgstr "Some random translation"
+
+msgctxt "Ctx"
+msgid "Some random in a context"
+msgstr "Some random translation in a context"
+
+msgid "More"
+msgstr "More translation"
+
+    `
+
+	// Create Locales directory on default location
+	dirname := path.Clean("/tmp" + string(os.PathSeparator) + "en_US")
+	err := os.MkdirAll(dirname, os.ModePerm)
+	if err != nil {
+		t.Fatalf("Can't create test directory: %s", err.Error())
+	}
+
+	// Write PO content to default domain file
+	filename := path.Clean(dirname + string(os.PathSeparator) + "default.po")
+
+	f, err := os.Create(filename)
+	if err != nil {
+		t.Fatalf("Can't create test file: %s", err.Error())
+	}
+	defer f.Close()
+
+	_, err = f.WriteString(str)
+	if err != nil {
+		t.Fatalf("Can't write to test file: %s", err.Error())
+	}
+
+	// Set package configuration
+	Configure("/tmp", "en_US", "default")
+
+	// Test translations
+	tr := Get("My text")
+	if tr != "Translated text" {
+		t.Errorf("Expected 'Translated text' but got '%s'", tr)
+	}
+
+	v := "Variable"
+	tr = Get("One with var: %s", v)
+	if tr != "This one is the singular: Variable" {
+		t.Errorf("Expected 'This one is the singular: Variable' but got '%s'", tr)
+	}
+
+	// Test plural
+	tr = GetN("One with var: %s", "Several with vars: %s", 2, v)
+	if tr != "And this is the second plural form: Variable" {
+		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
+	}
+
+	// Test context translations
+	tr = GetC("Some random in a context", "Ctx")
+	if tr != "Some random translation in a context" {
+		t.Errorf("Expected 'Some random translation in a context' but got '%s'", tr)
+	}
+
+	v = "Variable"
+	tr = GetC("One with var: %s", "Ctx", v)
+	if tr != "This one is the singular in a Ctx context: Variable" {
+		t.Errorf("Expected 'This one is the singular in a Ctx context: Variable' but got '%s'", tr)
+	}
+
+	tr = GetNC("One with var: %s", "Several with vars: %s", 1, "Ctx", v)
+	if tr != "This one is the plural in a Ctx context: Variable" {
+		t.Errorf("Expected 'This one is the plural in a Ctx context: Variable' but got '%s'", tr)
+	}
+}
+
+func TestPackageRace(t *testing.T) {
+	// Set PO content
+	str := `# Some comment
+msgid "My text"
+msgstr "Translated text"
+
+# More comments
+msgid "Another string"
+msgstr ""
+
 msgid "One with var: %s"
 msgid_plural "Several with vars: %s"
 msgstr[0] "This one is the singular: %s"
@@ -45,21 +170,20 @@ msgstr[2] "And this is the second plural form: %s"
 		t.Fatalf("Can't write to test file: %s", err.Error())
 	}
 
+	// Init sync channels
+	c1 := make(chan bool)
+	c2 := make(chan bool)
+
 	// Test translations
-	tr := Get("My text")
-	if tr != "Translated text" {
-		t.Errorf("Expected 'Translated text' but got '%s'", tr)
-	}
+	go func(done chan bool) {
+		Get("My text")
+		done <- true
+	}(c1)
 
-	v := "Variable"
-	tr = Get("One with var: %s", v)
-	if tr != "This one is the singular: Variable" {
-		t.Errorf("Expected 'This one is the singular: Variable' but got '%s'", tr)
-	}
+	go func(done chan bool) {
+		Get("My text")
+		done <- true
+	}(c2)
 
-	// Test plural
-	tr = GetN("One with var: %s", "Several with vars: %s", 2, v)
-	if tr != "And this is the second plural form: Variable" {
-		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
-	}
+	Get("My text")
 }

locale.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"sync"
 )
 
 /*
@@ -19,13 +20,13 @@ Example:
         // Create Locale with library path and language code
         l := gotext.NewLocale("/path/to/i18n/dir", "en_US")
 
-        // Load domain '/path/to/i18n/dir/en_US/default.po'
+        // Load domain '/path/to/i18n/dir/en_US/LC_MESSAGES/default.po'
         l.AddDomain("default")
 
         // Translate text from default domain
         println(l.Get("Translate this"))
 
-        // Load different domain ('/path/to/i18n/dir/en_US/extras.po')
+        // Load different domain ('/path/to/i18n/dir/en_US/LC_MESSAGES/extras.po')
         l.AddDomain("extras")
 
         // Translate text from domain
@@ -42,6 +43,9 @@ type Locale struct {
 
 	// List of available domains for this locale.
 	domains map[string]*Po
+
+	// Sync Mutex
+	sync.RWMutex
 }
 
 // NewLocale creates and initializes a new Locale object for a given language.
@@ -54,25 +58,43 @@ func NewLocale(p, l string) *Locale {
 	}
 }
 
+func (l *Locale) findPO(dom string) string {
+	filename := path.Join(l.path, l.lang, "LC_MESSAGES", dom+".po")
+	if _, err := os.Stat(filename); err == nil {
+		return filename
+	}
+
+	if len(l.lang) > 2 {
+		filename = path.Join(l.path, l.lang[:2], "LC_MESSAGES", dom+".po")
+		if _, err := os.Stat(filename); err == nil {
+			return filename
+		}
+	}
+
+	filename = path.Join(l.path, l.lang, dom+".po")
+	if _, err := os.Stat(filename); err == nil {
+		return filename
+	}
+
+	if len(l.lang) > 2 {
+		filename = path.Join(l.path, l.lang[:2], dom+".po")
+	}
+
+	return filename
+}
+
 // AddDomain creates a new domain for a given locale object and initializes the Po object.
 // If the domain exists, it gets reloaded.
 func (l *Locale) AddDomain(dom string) {
 	po := new(Po)
 
-	// Check for file.
-	filename := path.Clean(l.path + string(os.PathSeparator) + l.lang + string(os.PathSeparator) + dom + ".po")
-
-	// Try to use the generic language dir if the provided isn't available
-	if _, err := os.Stat(filename); err != nil {
-		if len(l.lang) > 2 {
-			filename = path.Clean(l.path + string(os.PathSeparator) + l.lang[:2] + string(os.PathSeparator) + dom + ".po")
-		}
-	}
-
 	// Parse file.
-	po.ParseFile(filename)
+	po.ParseFile(l.findPO(dom))
 
 	// Save new domain
+	l.Lock()
+	defer l.Unlock()
+
 	if l.domains == nil {
 		l.domains = make(map[string]*Po)
 	}
@@ -92,16 +114,20 @@ func (l *Locale) GetN(str, plural string, n int, vars ...interface{}) string {
 	return l.GetND("default", str, plural, n, vars...)
 }
 
-// GetD returns the corresponding translation in the given domain for a given string.
+// GetD returns the corresponding translation in the given domain for the given string.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) GetD(dom, str string, vars ...interface{}) string {
 	return l.GetND(dom, str, str, 0, vars...)
 }
 
-// GetND retrieves the (N)th plural form translation in the given domain for a given string.
+// GetND retrieves the (N)th plural form translation in the given domain for the given string.
 // If n == 0, usually the singular form of the string is returned as defined in the PO file.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) GetND(dom, str, plural string, n int, vars ...interface{}) string {
+	// Sync read
+	l.RLock()
+	defer l.RUnlock()
+
 	if l.domains != nil {
 		if _, ok := l.domains[dom]; ok {
 			if l.domains[dom] != nil {
@@ -113,3 +139,42 @@ func (l *Locale) GetND(dom, str, plural string, n int, vars ...interface{}) stri
 	// Return the same we received by default
 	return fmt.Sprintf(plural, vars...)
 }
+
+// GetC uses a domain "default" to return the corresponding translation of the given string in the given context.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (l *Locale) GetC(str, ctx string, vars ...interface{}) string {
+	return l.GetDC("default", str, ctx, vars...)
+}
+
+// GetNC retrieves the (N)th plural form translation for the given string in the given context in the "default" domain.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (l *Locale) GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
+	return l.GetNDC("default", str, plural, n, ctx, vars...)
+}
+
+// GetDC returns the corresponding translation in the given domain for the given string in the given context.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (l *Locale) GetDC(dom, str, ctx string, vars ...interface{}) string {
+	return l.GetNDC(dom, str, str, 0, ctx, vars...)
+}
+
+// GetNDC retrieves the (N)th plural form translation in the given domain for the given string in the given context.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (l *Locale) GetNDC(dom, str, plural string, n int, ctx string, vars ...interface{}) string {
+	// Sync read
+	l.RLock()
+	defer l.RUnlock()
+
+	if l.domains != nil {
+		if _, ok := l.domains[dom]; ok {
+			if l.domains[dom] != nil {
+				return l.domains[dom].GetNC(str, plural, n, ctx, vars...)
+			}
+		}
+	}
+
+	// Return the same we received by default
+	return fmt.Sprintf(plural, vars...)
+}

locale_test.go

@@ -22,17 +22,41 @@ msgstr[0] "This one is the singular: %s"
 msgstr[1] "This one is the plural: %s"
 msgstr[2] "And this is the second plural form: %s"
 
+msgid "This one has invalid syntax translations"
+msgid_plural "Plural index"
+msgstr[abc] "Wrong index"
+msgstr[1 "Forgot to close brackets"
+msgstr[0] "Badly formatted string'
+
+msgid "Invalid formatted id[] with no translations
+
+msgctxt "Ctx"
+msgid "One with var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular in a Ctx context: %s"
+msgstr[1] "This one is the plural in a Ctx context: %s"
+
+msgid "Some random"
+msgstr "Some random translation"
+
+msgctxt "Ctx"
+msgid "Some random in a context"
+msgstr "Some random translation in a context"
+
+msgid "More"
+msgstr "More translation"
+
     `
 
 	// Create Locales directory with simplified language code
-	dirname := path.Clean("/tmp" + string(os.PathSeparator) + "en")
+	dirname := path.Join("/tmp", "en", "LC_MESSAGES")
 	err := os.MkdirAll(dirname, os.ModePerm)
 	if err != nil {
 		t.Fatalf("Can't create test directory: %s", err.Error())
 	}
 
 	// Write PO content to file
-	filename := path.Clean(dirname + string(os.PathSeparator) + "my_domain.po")
+	filename := path.Join(dirname, "my_domain.po")
 
 	f, err := os.Create(filename)
 	if err != nil {
@@ -48,6 +72,9 @@ msgstr[2] "And this is the second plural form: %s"
 	// Create Locale with full language code
 	l := NewLocale("/tmp", "en_US")
 
+	// Force nil domain storage
+	l.domains = nil
+
 	// Add domain
 	l.AddDomain("my_domain")
 
@@ -68,4 +95,122 @@ msgstr[2] "And this is the second plural form: %s"
 	if tr != "And this is the second plural form: Variable" {
 		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
 	}
+
+	// Test non-existent "deafult" domain responses
+	tr = l.Get("My text")
+	if tr != "My text" {
+		t.Errorf("Expected 'My text' but got '%s'", tr)
+	}
+
+	tr = l.GetN("One with var: %s", "Several with vars: %s", 2, v)
+	if tr != "Several with vars: Variable" {
+		t.Errorf("Expected 'Several with vars: Variable' but got '%s'", tr)
+	}
+
+	// Test inexistent translations
+	tr = l.Get("This is a test")
+	if tr != "This is a test" {
+		t.Errorf("Expected 'This is a test' but got '%s'", tr)
+	}
+
+	tr = l.GetN("This is a test", "This are tests", 1)
+	if tr != "This are tests" {
+		t.Errorf("Expected 'This are tests' but got '%s'", tr)
+	}
+
+	// Test syntax error parsed translations
+	tr = l.Get("This one has invalid syntax translations")
+	if tr != "This one has invalid syntax translations" {
+		t.Errorf("Expected 'This one has invalid syntax translations' but got '%s'", tr)
+	}
+
+	tr = l.GetN("This one has invalid syntax translations", "This are tests", 1)
+	if tr != "This are tests" {
+		t.Errorf("Expected 'Plural index' but got '%s'", tr)
+	}
+
+	// Test context translations
+	v = "Test"
+	tr = l.GetDC("my_domain", "One with var: %s", "Ctx", v)
+	if tr != "This one is the singular in a Ctx context: Test" {
+		t.Errorf("Expected 'This one is the singular in a Ctx context: Test' but got '%s'", tr)
+	}
+
+	// Test plural
+	tr = l.GetNDC("my_domain", "One with var: %s", "Several with vars: %s", 1, "Ctx", v)
+	if tr != "This one is the plural in a Ctx context: Test" {
+		t.Errorf("Expected 'This one is the plural in a Ctx context: Test' but got '%s'", tr)
+	}
+
+	// Test last translation
+	tr = l.GetD("my_domain", "More")
+	if tr != "More translation" {
+		t.Errorf("Expected 'More translation' but got '%s'", tr)
+	}
+}
+
+func TestLocaleRace(t *testing.T) {
+	// Set PO content
+	str := `# Some comment
+msgid "My text"
+msgstr "Translated text"
+
+# More comments
+msgid "Another string"
+msgstr ""
+
+msgid "One with var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular: %s"
+msgstr[1] "This one is the plural: %s"
+msgstr[2] "And this is the second plural form: %s"
+
+    `
+
+	// Create Locales directory with simplified language code
+	dirname := path.Join("/tmp", "es")
+	err := os.MkdirAll(dirname, os.ModePerm)
+	if err != nil {
+		t.Fatalf("Can't create test directory: %s", err.Error())
+	}
+
+	// Write PO content to file
+	filename := path.Join(dirname, "race.po")
+
+	f, err := os.Create(filename)
+	if err != nil {
+		t.Fatalf("Can't create test file: %s", err.Error())
+	}
+	defer f.Close()
+
+	_, err = f.WriteString(str)
+	if err != nil {
+		t.Fatalf("Can't write to test file: %s", err.Error())
+	}
+
+	// Create Locale with full language code
+	l := NewLocale("/tmp", "es")
+
+	// Init sync channels
+	ac := make(chan bool)
+	rc := make(chan bool)
+
+	// Add domain in goroutine
+	go func(l *Locale, done chan bool) {
+		l.AddDomain("race")
+		done <- true
+	}(l, ac)
+
+	// Get translations in goroutine
+	go func(l *Locale, done chan bool) {
+		l.GetD("race", "My text")
+		done <- true
+	}(l, rc)
+
+	// Get translations at top level
+	l.GetD("race", "My text")
+
+	// Wait for goroutines to finish
+	<-ac
+	<-rc
 }

po.go

@@ -66,6 +66,7 @@ Example:
 type Po struct {
 	// Storage
 	translations map[string]*translation
+	contexts     map[string]map[string]*translation
 
 	// Sync Mutex
 	sync.RWMutex
@@ -95,16 +96,23 @@ func (po *Po) ParseFile(f string) {
 
 // Parse loads the translations specified in the provided string (str)
 func (po *Po) Parse(str string) {
+	// Init storage
 	if po.translations == nil {
 		po.Lock()
 		po.translations = make(map[string]*translation)
+		po.contexts = make(map[string]map[string]*translation)
 		po.Unlock()
 	}
 
+	// Get lines
 	lines := strings.Split(str, "\n")
 
+	// Translation buffer
 	tr := newTranslation()
 
+	// Context buffer
+	ctx := ""
+
 	for _, l := range lines {
 		// Trim spaces
 		l = strings.TrimSpace(l)
@@ -115,19 +123,59 @@ func (po *Po) Parse(str string) {
 		}
 
 		// Skip invalid lines
-		if !strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") && !strings.HasPrefix(l, "msgstr") {
+		if !strings.HasPrefix(l, "msgctxt") && !strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") && !strings.HasPrefix(l, "msgstr") {
+			continue
+		}
+
+		// Buffer context and continue
+		if strings.HasPrefix(l, "msgctxt") {
+			// Save current translation buffer.
+			po.Lock()
+			// No context
+			if ctx == "" {
+				po.translations[tr.id] = tr
+			} else {
+				// Save context
+				if _, ok := po.contexts[ctx]; !ok {
+					po.contexts[ctx] = make(map[string]*translation)
+				}
+				po.contexts[ctx][tr.id] = tr
+			}
+			po.Unlock()
+
+			// Flush buffer
+			tr = newTranslation()
+			ctx = ""
+
+			// Buffer context
+			ctx, _ = strconv.Unquote(strings.TrimSpace(strings.TrimPrefix(l, "msgctxt")))
+
+			// Loop
 			continue
 		}
 
 		// Buffer msgid and continue
 		if strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") {
-			// Save current translation buffer.
+			// Save current translation buffer if not inside a context.
+			if ctx == "" {
 				po.Lock()
 				po.translations[tr.id] = tr
 				po.Unlock()
 
 				// Flush buffer
 				tr = newTranslation()
+				ctx = ""
+			} else if ctx != "" && tr.id != "" {
+				// Save current translation buffer inside a context
+				if _, ok := po.contexts[ctx]; !ok {
+					po.contexts[ctx] = make(map[string]*translation)
+				}
+				po.contexts[ctx][tr.id] = tr
+
+				// Flush buffer
+				tr = newTranslation()
+				ctx = ""
+			}
 
 			// Set id
 			tr.id, _ = strconv.Unquote(strings.TrimSpace(strings.TrimPrefix(l, "msgid")))
@@ -178,7 +226,15 @@ func (po *Po) Parse(str string) {
 	// Save last translation buffer.
 	if tr.id != "" {
 		po.Lock()
+		if ctx == "" {
 			po.translations[tr.id] = tr
+		} else {
+			// Save context
+			if _, ok := po.contexts[ctx]; !ok {
+				po.contexts[ctx] = make(map[string]*translation)
+			}
+			po.contexts[ctx][tr.id] = tr
+		}
 		po.Unlock()
 	}
 }
@@ -186,6 +242,10 @@ func (po *Po) Parse(str string) {
 // Get retrieves the corresponding translation for the given string.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (po *Po) Get(str string, vars ...interface{}) string {
+	// Sync read
+	po.RLock()
+	defer po.RUnlock()
+
 	if po.translations != nil {
 		if _, ok := po.translations[str]; ok {
 			return fmt.Sprintf(po.translations[str].get(), vars...)
@@ -200,6 +260,10 @@ func (po *Po) Get(str string, vars ...interface{}) string {
 // If n == 0, usually the singular form of the string is returned as defined in the PO file.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (po *Po) GetN(str, plural string, n int, vars ...interface{}) string {
+	// Sync read
+	po.RLock()
+	defer po.RUnlock()
+
 	if po.translations != nil {
 		if _, ok := po.translations[str]; ok {
 			return fmt.Sprintf(po.translations[str].getN(n), vars...)
@@ -209,3 +273,46 @@ func (po *Po) GetN(str, plural string, n int, vars ...interface{}) string {
 	// Return the plural string we received by default
 	return fmt.Sprintf(plural, vars...)
 }
+
+// GetC retrieves the corresponding translation for a given string in the given context.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (po *Po) GetC(str, ctx string, vars ...interface{}) string {
+	// Sync read
+	po.RLock()
+	defer po.RUnlock()
+
+	if po.contexts != nil {
+		if _, ok := po.contexts[ctx]; ok {
+			if po.contexts[ctx] != nil {
+				if _, ok := po.contexts[ctx][str]; ok {
+					return fmt.Sprintf(po.contexts[ctx][str].get(), vars...)
+				}
+			}
+		}
+	}
+
+	// Return the string we received by default
+	return fmt.Sprintf(str, vars...)
+}
+
+// GetNC retrieves the (N)th plural form translation for the given string in the given context.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (po *Po) GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
+	// Sync read
+	po.RLock()
+	defer po.RUnlock()
+
+	if po.contexts != nil {
+		if _, ok := po.contexts[ctx]; ok {
+			if po.contexts[ctx] != nil {
+				if _, ok := po.contexts[ctx][str]; ok {
+					return fmt.Sprintf(po.contexts[ctx][str].getN(n), vars...)
+				}
+			}
+		}
+	}
+
+	// Return the plural string we received by default
+	return fmt.Sprintf(plural, vars...)
+}

po_test.go

@@ -22,7 +22,31 @@ msgstr[0] "This one is the singular: %s"
 msgstr[1] "This one is the plural: %s"
 msgstr[2] "And this is the second plural form: %s"
 
+msgid "This one has invalid syntax translations"
+msgid_plural "Plural index"
+msgstr[abc] "Wrong index"
+msgstr[1 "Forgot to close brackets"
+msgstr[0] "Badly formatted string'
+
+msgid "Invalid formatted id[] with no translations
+
+msgctxt "Ctx"
+msgid "One with var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular in a Ctx context: %s"
+msgstr[1] "This one is the plural in a Ctx context: %s"
+
+msgid "Some random"
+msgstr "Some random translation"
+
+msgctxt "Ctx"
+msgid "Some random in a context"
+msgstr "Some random translation in a context"
+
+msgid "More"
+msgstr "More translation"
     `
+
 	// Write PO content to file
 	filename := path.Clean(os.TempDir() + string(os.PathSeparator) + "default.po")
 
@@ -37,8 +61,13 @@ msgstr[2] "And this is the second plural form: %s"
 		t.Fatalf("Can't write to test file: %s", err.Error())
 	}
 
-	// Parse po file
+	// Create po object
 	po := new(Po)
+
+	// Try to parse a directory
+	po.ParseFile(path.Clean(os.TempDir()))
+
+	// Parse file
 	po.ParseFile(filename)
 
 	// Test translations
@@ -58,4 +87,110 @@ msgstr[2] "And this is the second plural form: %s"
 	if tr != "And this is the second plural form: Variable" {
 		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
 	}
+
+	// Test inexistent translations
+	tr = po.Get("This is a test")
+	if tr != "This is a test" {
+		t.Errorf("Expected 'This is a test' but got '%s'", tr)
+	}
+
+	tr = po.GetN("This is a test", "This are tests", 1)
+	if tr != "This are tests" {
+		t.Errorf("Expected 'This are tests' but got '%s'", tr)
+	}
+
+	// Test syntax error parsed translations
+	tr = po.Get("This one has invalid syntax translations")
+	if tr != "" {
+		t.Errorf("Expected '' but got '%s'", tr)
+	}
+
+	tr = po.GetN("This one has invalid syntax translations", "This are tests", 1)
+	if tr != "Plural index" {
+		t.Errorf("Expected 'Plural index' but got '%s'", tr)
+	}
+
+	// Test context translations
+	v = "Test"
+	tr = po.GetC("One with var: %s", "Ctx", v)
+	if tr != "This one is the singular in a Ctx context: Test" {
+		t.Errorf("Expected 'This one is the singular in a Ctx context: Test' but got '%s'", tr)
+	}
+
+	// Test plural
+	tr = po.GetNC("One with var: %s", "Several with vars: %s", 1, "Ctx", v)
+	if tr != "This one is the plural in a Ctx context: Test" {
+		t.Errorf("Expected 'This one is the plural in a Ctx context: Test' but got '%s'", tr)
+	}
+
+	// Test last translation
+	tr = po.Get("More")
+	if tr != "More translation" {
+		t.Errorf("Expected 'More translation' but got '%s'", tr)
+	}
+
+}
+
+func TestTranslationObject(t *testing.T) {
+	tr := newTranslation()
+	str := tr.get()
+
+	if str != "" {
+		t.Errorf("Expected '' but got '%s'", str)
+	}
+
+	// Set id
+	tr.id = "Text"
+
+	// Get again
+	str = tr.get()
+
+	if str != "Text" {
+		t.Errorf("Expected 'Text' but got '%s'", str)
+	}
+}
+
+func TestPoRace(t *testing.T) {
+	// Set PO content
+	str := `# Some comment
+msgid "My text"
+msgstr "Translated text"
+
+# More comments
+msgid "Another string"
+msgstr ""
+
+msgid "One with var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular: %s"
+msgstr[1] "This one is the plural: %s"
+msgstr[2] "And this is the second plural form: %s"
+
+    `
+
+	// Create Po object
+	po := new(Po)
+
+	// Create sync channels
+	pc := make(chan bool)
+	rc := make(chan bool)
+
+	// Parse po content in a goroutine
+	go func(po *Po, done chan bool) {
+		po.Parse(str)
+		done <- true
+	}(po, pc)
+
+	// Read some translation on a goroutine
+	go func(po *Po, done chan bool) {
+		po.Get("My text")
+		done <- true
+	}(po, rc)
+
+	// Read something at top level
+	po.Get("My text")
+
+	// Wait for goroutines to finish
+	<-pc
+	<-rc
 }