[NaCl SDK] Google Drive example

native_client_sdk/src/examples/demo/drive/drive.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <string>
+#include <vector>
+
+#include "json/reader.h"
+#include "json/writer.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/url_loader.h"
+#include "ppapi/cpp/url_request_info.h"
+#include "ppapi/cpp/url_response_info.h"
+#include "ppapi/cpp/var.h"
+#include "ppapi/utility/completion_callback_factory.h"
+
+namespace {
+
+const char kTokenMessage[] = "token:";
+const char kGetFileMessage[] = "getFile";
+const char kBoundary[] = "NACL_BOUNDARY_600673";
+
+std::string EncodeUriComponent(const std::string& s) {
+  char hex[] = "0123456789ABCDEF";
+  std::string result;
+  for (size_t i = 0; i < s.length(); ++i) {
+    char c = s[i];
+    if (isalpha(c) || isdigit(c) || strchr("-_.!~*'()", c)) {
+      result += c;
+    } else {
+      result += '%';
+      result += hex[(c >> 4) & 0xf];
+      result += hex[c & 0xf];
+    }
+  }
+  return result;
+}
+
+std::string IntToString(int x) {
+  char buffer[32];
+  snprintf(&buffer[0], 32, "%d", x);
+  return &buffer[0];
+}
+
+void AddQueryParameter(std::string* s,

[noelallen1, 2013/04/30 18:46:08]

Incorrect indent.

[binji, 2013/04/30 20:07:27]

Done.

+                              const std::string& key,
+                              const std::string& value,
+                              bool first) {
+  *s += first ? '?' : '&';
+  *s += EncodeUriComponent(key);
+  *s += '=';
+  *s += EncodeUriComponent(value);
+}
+
+void AddQueryParameter(std::string* s,
+                              const std::string& key,
+                              int value,
+                              bool first) {
+  AddQueryParameter(s, key, IntToString(value), first);
+}
+
+void AddAuthTokenHeader(std::string* s, const std::string& auth_token) {
+  *s += "Authorization: Bearer ";
+  *s += auth_token;
+  *s += "\n";
+}
+
+void AddHeader(std::string* s,
+                      const char* key,
+                      const std::string& value) {
+  *s += key;
+  *s += ": ";
+  *s += value;
+  *s += "\n";
+}
+
+}  // namespace
+
+//
+// UrlReader
+//
+struct UrlReaderParams {
+  std::string url;
+  std::string method;
+  std::string request_headers;
+  std::string request_body;
+};
+
+int32_t ReadUrl(pp::Instance* instance,
+                const UrlReaderParams& params,
+                std::string* output) {
+  pp::URLRequestInfo url_request(instance);
+  pp::URLLoader url_loader(instance);
+
+  url_request.SetURL(params.url);
+  url_request.SetMethod(params.method);
+  url_request.SetHeaders(params.request_headers);
+  url_request.SetRecordDownloadProgress(true);
+  if (params.request_body.size()) {
+    url_request.AppendDataToBody(params.request_body.data(),
+                                 params.request_body.size());
+  }
+
+  int32_t result = url_loader.Open(url_request, pp::BlockUntilComplete());
+  if (result != PP_OK) {
+    return result;
+  }
+
+  pp::URLResponseInfo url_response = url_loader.GetResponseInfo();
+  if (url_response.GetStatusCode() != 200)
+    return PP_ERROR_FAILED;
+
+  output->clear();
+
+  int64_t bytes_received = 0;
+  int64_t total_bytes_to_be_received = 0;
+  if (url_loader.GetDownloadProgress(&bytes_received,
+                                     &total_bytes_to_be_received)) {
+    if (total_bytes_to_be_received > 0) {
+      output->reserve(total_bytes_to_be_received);
+    }
+  }
+
+  url_request.SetRecordDownloadProgress(false);
+
+  const size_t kReadBufferSize = 16 * 1024;
+  uint8_t* buffer_ = new uint8_t[kReadBufferSize];
+
+  do {
+    result = url_loader.ReadResponseBody(
+        buffer_, kReadBufferSize, pp::BlockUntilComplete());
+    if (result > 0) {
+      size_t num_bytes =
+          result > kReadBufferSize ? kReadBufferSize : result;
+      output->insert(output->end(), buffer_, buffer_ + num_bytes);
+    }
+  } while (result > 0);
+
+  delete[] buffer_;
+
+  return result;
+}
+
+//
+// FilesList
+//
+struct FilesListParams {
+  int max_results;
+  std::string page_token;
+  std::string q;
+};
+
+int32_t ListFiles(pp::Instance* instance,
+                  const std::string& auth_token,
+                  const FilesListParams& params,
+                  Json::Value* root) {
+  static const char base_url[] = "https://www.googleapis.com/drive/v2/files";
+
+  UrlReaderParams p;
+  p.method = "GET";
+  p.url = base_url;
+  AddQueryParameter(&p.url, "maxResults", params.max_results, true);
+  if (params.page_token.length())
+    AddQueryParameter(&p.url, "pageToken", params.page_token, false);
+  AddQueryParameter(&p.url, "q", params.q, false);
+  AddQueryParameter(&p.url, "fields", "items(id,downloadUrl)", false);
+  AddAuthTokenHeader(&p.request_headers, auth_token);
+
+  std::string output;
+  int32_t result = ReadUrl(instance, p, &output);
+  if (result != PP_OK) {
+    return result;
+  }
+
+  Json::Reader reader(Json::Features::strictMode());
+  if (!reader.parse(output, *root, false)) {
+    return PP_ERROR_FAILED;
+  }
+
+  return PP_OK;
+}
+
+//
+// FilesInsert
+//
+struct FilesInsertParams {
+  std::string file_id;
+  std::string content;
+  std::string description;
+  std::string mime_type;
+  std::string title;
+};
+
+std::string BuildRequestBody(const FilesInsertParams& params) {
+  std::string result;
+  result += "--";
+  result += kBoundary;
+  result += "\nContent-Type: application/json; charset=UTF-8\n\n";
+
+  Json::Value value(Json::objectValue);
+  if (!params.description.empty())
+    value["description"] = Json::Value(params.description);
+
+  if (!params.mime_type.empty())
+    value["mimeType"] = Json::Value(params.mime_type);
+
+  if (!params.title.empty())
+    value["title"] = Json::Value(params.title);
+
+  Json::FastWriter writer;
+  std::string metadata = writer.write(value);
+
+  result += metadata;
+  result += "--";
+  result += kBoundary;
+  result += "\nContent-Type: ";
+  result += params.mime_type;
+  result += "\n\n";
+  result += params.content;
+  result += "\n--";
+  result += kBoundary;
+  result += "--";
+  return result;
+}
+
+int32_t InsertFile(pp::Instance* instance,
+                   const std::string& auth_token,
+                   const FilesInsertParams& params,
+                   Json::Value* root) {
+  static const char base_url[] =
+      "https://www.googleapis.com/upload/drive/v2/files";
+  const char* method = "POST";
+
+  UrlReaderParams p;
+  p.url = base_url;
+
+  // If file_id is defined, we are actually updating an existing file.
+  if (!params.file_id.empty()) {
+    p.url += "/";
+    p.url += params.file_id;
+    p.method = "PUT";
+  } else {
+    p.method = "POST";
+  }
+
+  AddQueryParameter(&p.url, "uploadType", "multipart", true);
+  AddQueryParameter(&p.url, "fields", "id,downloadUrl", false);
+  AddAuthTokenHeader(&p.request_headers, auth_token);
+  AddHeader(&p.request_headers,
+            "Content-Type",
+            std::string("multipart/related; boundary=") + kBoundary + "\n");
+  p.request_body = BuildRequestBody(params);
+
+  std::string output;
+  int32_t result = ReadUrl(instance, p, &output);
+  if (result != PP_OK) {
+    return result;
+  }
+
+  Json::Reader reader(Json::Features::strictMode());
+  if (!reader.parse(output, *root, false)) {
+    return PP_ERROR_FAILED;
+  }
+
+  return PP_OK;
+}
+
+//
+// Instance
+//
+class Instance : public pp::Instance {
+ public:
+  explicit Instance(PP_Instance instance);
+  virtual ~Instance();
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]);
+  virtual void HandleMessage(const pp::Var& var_message);
+
+  void PostMessagef(const char* format, ...);
+
+ private:
+  static void* ThreadThunk(void* param);
+  void ThreadMainLoop();
+  bool ThreadRequest();
+  bool ThreadGetFileMetadata(const char* title, Json::Value* metadata);
+  bool ThreadCreateFile(const char* title,
+                        const char* description,
+                        const char* content,
+                        Json::Value* metadata);
+  bool ThreadUpdateFile(const std::string& file_id,
+                        const std::string& content,
+                        Json::Value* metadata);
+  bool ThreadDownloadFile(const Json::Value& metadata, std::string* output);
+  bool GetMetadataKey(const Json::Value& metadata,
+                      const char* key,
+                      std::string* output);
+
+  std::string auth_token_;
+  pthread_t thread_;
+  pthread_mutex_t mutex_;
+  pthread_cond_t cond_;
+  bool has_request_;
+};
+
+Instance::Instance(PP_Instance instance) : pp::Instance(instance) {}
+
+Instance::~Instance() {}

[noelallen1, 2013/04/30 18:46:08]

required?

[binji, 2013/04/30 20:07:27]

Done.

+
+bool Instance::Init(uint32_t argc, const char* argn[], const char* argv[]) {

[noelallen1, 2013/04/30 18:46:08]

Unused args.  We should be consistent, see file_io:
  virtual bool Init(uint32_t /*argc*/, const char* /*argn*/[],
      const char* /*argv*/[])

[binji, 2013/04/30 20:07:27]

Done.

+  pthread_create(&thread_, NULL, &Instance::ThreadThunk, this);
+  pthread_mutex_init(&mutex_, NULL);
+  pthread_cond_init(&cond_, NULL);
+  return true;
+}
+
+void Instance::HandleMessage(const pp::Var& var_message) {
+  if (!var_message.is_string()) {
+    return;
+  }
+
+  std::string message = var_message.AsString();
+  if (!strncmp(message.c_str(), kTokenMessage, strlen(kTokenMessage))) {
+    // Auth token
+    auth_token_ = message.c_str() + strlen(kTokenMessage);

[noelallen1, 2013/04/30 18:46:08]

message.subst(strlen(kTokenMessage))?

[noelallen1, 2013/04/30 18:46:08]

Is this thread safe?  You are setting auth_token_ in one thread then using it in
the other?  Is it possible to get another auth_token message?

Would this all be cleaner if you used a message loop then let HandleMessage just
posted all string messages to the worker thread?  That should let you get rid of
the pthread mutex, cond_var, and simply issue a Run in your worker.

[binji, 2013/04/30 20:07:27]

Done.

+  } else if (!strncmp(
+                 message.c_str(), kGetFileMessage, strlen(kGetFileMessage))) {

[noelallen1, 2013/04/30 18:46:08]

message.compare(0, strlen(kGetFileMessage), kGetFileMessage)?

[binji, 2013/04/30 20:07:27]

Done.

+    // getFile
+    pthread_mutex_lock(&mutex_);
+    has_request_ = true;
+    pthread_cond_signal(&cond_);
+    pthread_mutex_unlock(&mutex_);
+  }
+}
+
+void Instance::PostMessagef(const char* format, ...) {
+  const size_t kBufferSize = 1024;
+  char buffer[kBufferSize];
+  va_list args;
+  va_start(args, format);
+  vsnprintf(&buffer[0], kBufferSize, format, args);
+
+  PostMessage(buffer);
+}
+
+// static
+void* Instance::ThreadThunk(void* param) {
+  static_cast<Instance*>(param)->ThreadMainLoop();
+  return NULL;
+}
+
+void Instance::ThreadMainLoop() {
+  while (1) {
+    pthread_mutex_lock(&mutex_);
+    while (!has_request_) {
+      pthread_cond_wait(&cond_, &mutex_);
+    }
+    has_request_ = false;
+    pthread_mutex_unlock(&mutex_);
+
+    // Perform the request.
+    ThreadRequest();
+  }
+}
+
+bool Instance::ThreadRequest() {
+  static int request_count = 0;
+  static const char kTitle[] = "hello nacl.txt";
+  Json::Value metadata;
+  std::string output;
+
+  PostMessagef("log:\n Got request (#%d).\n", ++request_count);
+  PostMessagef("log: Looking for file: \"%s\".\n", kTitle);
+
+  if (!ThreadGetFileMetadata(kTitle, &metadata)) {
+    PostMessagef("log: Not found! Creating a new file...\n");
+    // No data found, write a new file.
+    static const char kDescription[] = "A file generated by NaCl!";

[noelallen1, 2013/04/30 18:46:08]

Why is this local to ThreadRequest, but kToken is not local to HandleMessage?

[binji, 2013/04/30 20:07:27]

Done.

+    static const char kInitialContent[] = "Hello, Google Drive!";
+
+    if (!ThreadCreateFile(kTitle, kDescription, kInitialContent, &metadata)) {
+      PostMessagef("log: Creating the new file failed...\n");
+      return false;
+    }
+  } else {
+    PostMessagef("log: Found it! Downloading the file...\n");
+    // Found the file, download it's data.
+    output.clear();
+    if (!ThreadDownloadFile(metadata, &output)) {
+      PostMessagef("log: Downloading the file failed...\n");
+      return false;
+    }
+
+    // Modify it.
+    output += "\nHello, again Google Drive!";
+
+    std::string file_id;
+    if (!GetMetadataKey(metadata, "id", &file_id)) {
+      PostMessagef("log: Couldn't find the file id...\n");
+      return false;
+    }
+
+    PostMessagef("log: Updating the file...\n");
+    if (!ThreadUpdateFile(file_id, output, &metadata)) {
+      PostMessagef("log: Failed to update the file...\n");
+      return false;
+    }
+  }
+
+  PostMessagef("log: Done!\n");
+  PostMessagef("log: Downloading the newly written file...\n");
+  output.clear();
+  if (!ThreadDownloadFile(metadata, &output)) {
+    PostMessagef("log: Downloading the file failed...\n");
+    return false;
+  }
+
+  PostMessagef("log: Done!\n");
+  PostMessage(output);

[noelallen1, 2013/04/30 18:46:08]

Why PostMessage here but not above?  Both cases are implicit pp::Var
constructors.

[binji, 2013/04/30 20:07:27]

Done.

+  return true;
+}
+
+bool Instance::ThreadGetFileMetadata(const char* title, Json::Value* metadata) {
+  FilesListParams p;
+  p.max_results = 1;
+  p.q = "title = \'";

[noelallen1, 2013/04/30 18:46:08]

Var name p.q?

[binji, 2013/04/30 20:07:27]

Done.

+  p.q += title;
+  p.q += "\'";
+
+  Json::Value root;
+  int32_t result = ListFiles(this, auth_token_, p, &root);
+  if (result != PP_OK) {
+    PostMessagef("log: ListFiles failed with result %d\n", result);
+    return false;
+  }
+
+  // Extract the first item's metadata.
+  if (!root.isMember("items")) {
+    PostMessagef("log: ListFiles returned no items...\n");
+    return false;
+  }
+
+  Json::Value items = root["items"];
+  if (!items.isValidIndex(0)) {
+    PostMessage("log: Expected items[0] to be valid.\n");
+    return false;
+  }
+
+  *metadata = items[0U];
+  return true;
+}
+
+bool Instance::ThreadCreateFile(const char* title,
+                                const char* description,
+                                const char* content,
+                                Json::Value* metadata) {
+  FilesInsertParams p;
+  p.content = content;
+  p.description = description;
+  p.mime_type = "text/plain";
+  p.title = title;
+
+  int32_t result = InsertFile(this, auth_token_, p, metadata);
+  if (result != PP_OK) {
+    PostMessagef("log: Creating file failed with result %d\n", result);
+    return false;
+  }
+
+  return true;
+}
+
+bool Instance::ThreadUpdateFile(const std::string& file_id,
+                                const std::string& content,
+                                Json::Value* metadata) {
+  FilesInsertParams p;
+  p.file_id = file_id;
+  p.content = content;
+  p.mime_type = "text/plain";
+
+  int32_t result = InsertFile(this, auth_token_, p, metadata);
+  if (result != PP_OK) {
+    PostMessagef("log: Updating file failed with result %d\n", result);
+    return false;
+  }
+
+  return true;
+}
+
+bool Instance::ThreadDownloadFile(const Json::Value& metadata,
+                                  std::string* output) {
+  UrlReaderParams p;
+  p.method = "GET";
+
+  if (!GetMetadataKey(metadata, "downloadUrl", &p.url)) {
+    return false;
+  }
+
+  AddAuthTokenHeader(&p.request_headers, auth_token_);
+
+  int32_t result = ReadUrl(this, p, output);
+  if (result != PP_OK) {
+    PostMessagef("log: Downloading failed with result %d\n", result);
+    return false;
+  }
+
+  return true;
+}
+
+bool Instance::GetMetadataKey(const Json::Value& metadata,
+                              const char* key,
+                              std::string* output) {
+  Json::Value value = metadata[key];
+  if (!value.isString()) {
+    PostMessagef("log: Expected metadata.%s to be a string.\n", key);
+    return false;
+  }
+
+  *output = value.asString();
+  return true;
+}
+
+
+class Module : public pp::Module {
+ public:
+  Module() : pp::Module() {}
+  virtual ~Module() {}
+
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new Instance(instance);
+  }
+};
+
+namespace pp {
+
+Module* CreateModule() { return new ::Module(); }
+
+}  // namespace pp