Implement Process.cwd (#41)

* Implement `Process.cwd`
* Update `os` test suite

src/cli/modules.c

@@ -25,6 +25,7 @@ extern void fileWriteBytes(WrenVM* vm);
 extern void platformIsPosix(WrenVM* vm);
 extern void platformName(WrenVM* vm);
 extern void processAllArguments(WrenVM* vm);
+extern void processCwd(WrenVM* vm);
 extern void statPath(WrenVM* vm);
 extern void statBlockCount(WrenVM* vm);
 extern void statBlockSize(WrenVM* vm);
@@ -165,6 +166,7 @@ static ModuleRegistry modules[] =
     END_CLASS
     CLASS(Process)
       STATIC_METHOD("allArguments", processAllArguments)
+      STATIC_METHOD("cwd", processCwd)
     END_CLASS
   END_MODULE
   MODULE(repl)

src/module/os.c

@@ -1,4 +1,5 @@
 #include "os.h"
+#include "uv.h"
 #include "wren.h"
 
 #if __APPLE__
@@ -69,3 +70,18 @@ void processAllArguments(WrenVM* vm)
     wrenInsertInList(vm, 0, -1, 1);
   }
 }
+
+void processCwd(WrenVM* vm)
+{
+  wrenEnsureSlots(vm, 1);
+
+  char buffer[PATH_MAX * 4];
+  size_t length = sizeof(buffer);
+  if (uv_cwd(buffer, &length) != 0)
+  {
+    wrenSetSlotString(vm, 0, "Cannot get current working directory.");
+    return wrenAbortFiber(vm, 0);
+  }
+
+  wrenSetSlotString(vm, 0, buffer);
+}

src/module/os.wren

@@ -10,4 +10,5 @@ class Process {
   static arguments { allArguments[2..-1] }
 
   foreign static allArguments
+  foreign static cwd
 }

src/module/os.wren.inc

@@ -12,4 +12,5 @@ static const char* osModuleSource =
 "  static arguments { allArguments[2..-1] }\n"
 "\n"
 "  foreign static allArguments\n"
+"  foreign static cwd\n"
 "}\n";

test/os/process/cwd.wren

@@ -0,0 +1,8 @@
+import "io" for File, Directory
+import "os" for Process
+
+System.print(Process.cwd is String) // expect: true
+System.print(!Process.cwd.isEmpty) // expect: true
+System.print(Process.cwd.startsWith("/")) // expect: true
+System.print(File.realPath(Process.cwd) == Process.cwd) // expect: true
+System.print(Directory.exists(Process.cwd)) // expect: true