Support GLBIC example.

native_client_sdk/src/examples/dlopen/dlopen.cc

+// Copyright (c) 2012 The Native Client Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// @file
+/// This example demonstrates building a dynamic library which is loaded by the
+/// NaCl module.  To load the NaCl module, the browser first looks for the
+/// CreateModule() factory method (at the end of this file).  It calls
+/// CreateModule() once to load the module code from your .nexe.  After the
+/// .nexe code is loaded, CreateModule() is not called again.
+///
+/// Once the .nexe code is loaded, the browser then calls the CreateInstance()
+/// method on the object returned by CreateModule().  If the CreateInstance
+/// returns successfully, then Init function is called, which will load the
+/// shared object on a worker thread.  We use a worker because dlopen is
+/// a blocking call, which is not alowed on the main thread.
+
+#include <dlfcn.h> 
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+#include <ppapi/cpp/module.h>
+#include <ppapi/cpp/completion_callback.h>
+#include <ppapi/cpp/var.h>
+#include <ppapi/cpp/instance.h>
+
+#include "eightball.h"
+
+/// The Instance class.  One of these exists for each instance of your NaCl
+/// module on the web page.  The browser will ask the Module object to create
+/// a new Instance for each occurrence of the <embed> tag that has these
+/// attributes:
+/// <pre>
+///     type="application/x-nacl"
+///     nacl="dlopen.nmf"
+/// </pre>
+class dlOpenInstance : public pp::Instance {
+ public:
+  explicit dlOpenInstance(pp::Core *core, PP_Instance instance):
+    pp::Instance(instance) {
+    _dlhandle = NULL;
+    _eightball = NULL;
+    _core = core;
+    _tid = 0;
+  };
+  virtual ~dlOpenInstance(){};
+
+  // Helper function to post a message back to the JS and stdout functions.
+  void logmsg(const char* pStr){
+    PostMessage(pp::Var(pStr));
+    fprintf(stdout, pStr);
+  }
+
+  // Initialize the module, staring a worker thread to load the shared object.
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]){
+    logmsg("Spawning thread to cache .so files...");
+    if (pthread_create(&_tid, NULL, LoadLibrariesOnWorker, this)) {
+      logmsg("ERROR; pthread_create() failed.\n");
+      return false;
+    }
+    return true;
+  }
+
+  // This function is called on a worker thread, and will call dlopen to load
+  // the shared object.  In addition, note that this function does NOT call
+  // dlclose, which would close the shared object and unload it from memory.
+  void LoadLibrary()
+  {
+    const int32_t IMMEDIATELY = 0;
+    _dlhandle = dlopen("libeightball.so", RTLD_LAZY);
+    pp::CompletionCallback cc(LoadDoneCB, this);
+    _core->CallOnMainThread(IMMEDIATELY, cc , 0);
+  }
+
+  // This function will run on the main thread and use the handle it stored by
+  // the worker thread, assuming it successfully loaded, to get a pointer to the
+  // message function in the shared object.
+  void UseLibrary() {
+    if(this->_dlhandle == NULL){

[Brad Chen, 2012/01/31 22:29:54]

Google3 style prescribes a space after "if". Miss this one?

[noelallen1, 2012/02/01 17:46:10]

Done.

+      logmsg("libeightball.so did not load");
+    }
+    else {

[Brad Chen, 2012/01/31 22:29:54]

I don't particularly care for this formatting and I don't think it is google3
either. You should use "} else {\n", that is, no newline before the "else".
There are a few more of these below.

[noelallen1, 2012/02/01 17:46:10]

Done.

+      this->_eightball = (TYPE_eightball) dlsym(this->_dlhandle, "Magic8Ball");
+      if (NULL == this->_eightball) {
+          std::string ballmessage = "dlsym() returned NULL: ";
+          ballmessage += dlerror();
+          ballmessage += "\n";
+          logmsg(ballmessage.c_str());
+      }
+      else{
+        logmsg("Eightball loaded!");
+      }
+    }
+  }
+
+  // Called by the browser to handle the postMessage() call in Javascript.
+  virtual void HandleMessage(const pp::Var& var_message) {
+    if(NULL == this->_eightball){
+      logmsg("Eightball library not loaded");
+      return;
+    }
+
+    if (!var_message.is_string()) {
+      logmsg("Message is not a string.");
+      return;
+    }
+
+    std::string message = var_message.AsString();
+    if (message == "query") {
+      fprintf(stdout, "%s(%d) Got this far.\n", __FILE__, __LINE__);
+      std::string ballmessage = "!The Magic 8-Ball says: ";
+      ballmessage += this->_eightball();
+
+      logmsg(ballmessage.c_str());
+      fprintf(stdout, "%s(%d) Got this far.\n", __FILE__, __LINE__);
+    }
+    else {
+      std::string errormsg = "Unexpected message: ";
+      errormsg += message + "\n";
+      logmsg(errormsg.c_str());
+    }
+  }
+
+  static void* LoadLibrariesOnWorker(void *pInst) {
+    dlOpenInstance *inst = static_cast<dlOpenInstance *>(pInst);
+    inst->LoadLibrary();
+    return NULL;
+  }
+
+  static void LoadDoneCB(void *pInst, int32_t result) {
+    dlOpenInstance *inst = static_cast<dlOpenInstance *>(pInst);
+    inst->UseLibrary();
+  }
+
+ private:
+  void *_dlhandle;
+  TYPE_eightball _eightball;
+  pp::Core *_core;
+  pthread_t _tid;
+
+ };
+
+// The Module class.  The browser calls the CreateInstance() method to create
+// an instance of your NaCl module on the web page.  The browser creates a new
+// instance for each <embed> tag with type="application/x-nacl".
+class dlOpenModule : public pp::Module {
+   public:
+  dlOpenModule() : pp::Module() {}
+  virtual ~dlOpenModule() {}
+
+  // Create and return a dlOpenInstance object.
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new dlOpenInstance(core(), instance);
+  }
+};
+
+
+// Factory function called by the browser when the module is first loaded.
+// The browser keeps a singleton of this module.  It calls the
+// CreateInstance() method on the object you return to make instances.  There
+// is one instance per <embed> tag on the page.  This is the main binding
+// point for your NaCl module with the browser.
+namespace pp {
+  Module* CreateModule() {
+    return new dlOpenModule();
+  }
+}  // namespace pp
+