[NaCl SDK] nacl_io: big refactor to return error value (errno).

native_client_sdk/src/libraries/nacl_io/mount_http.cc

Index: native_client_sdk/src/libraries/nacl_io/mount_http.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_http.cc b/native_client_sdk/src/libraries/nacl_io/mount_http.cc
index 9e6155f145bf87ff998d39a06cb8a5578f929a8e..7b4316e8428e7c52a8f18a212ced961b698fe5c6 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_http.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_http.cc
@@ -4,30 +4,30 @@
  */
 
 #include "nacl_io/mount_http.h"
+
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <ppapi/c/pp_errors.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+
 #include <vector>
+
+#include <ppapi/c/pp_errors.h>
+
 #include "nacl_io/mount_node_dir.h"
+#include "nacl_io/mount_node_http.h"
 #include "nacl_io/osinttypes.h"
 #include "sdk_util/auto_lock.h"
 
-#if defined(WIN32)
-#define snprintf _snprintf
-#endif
-
-
 namespace {
 
-typedef std::vector<char *> StringList_t;
-size_t SplitString(char *str, const char *delim, StringList_t* list) {
-  char *item = strtok(str, delim);
+typedef std::vector<char*> StringList_t;
+size_t SplitString(char* str, const char* delim, StringList_t* list) {
+  char* item = strtok(str, delim);
 
   list->clear();
   while (item) {
@@ -38,13 +38,7 @@ size_t SplitString(char *str, const char *delim, StringList_t* list) {
   return list->size();
 }
 
-
-// If we're attempting to read a partial request, but the server returns a full
-// request, we need to read all of the data up to the start of our partial
-// request into a dummy buffer. This is the maximum size of that buffer.
-const size_t MAX_READ_BUFFER_SIZE = 64 * 1024;
-const int32_t STATUSCODE_OK = 200;
-const int32_t STATUSCODE_PARTIAL_CONTENT = 206;
+}  // namespace
 
 std::string NormalizeHeaderKey(const std::string& s) {
   // Capitalize the first letter and any letter following a hyphen:
@@ -60,557 +54,64 @@ std::string NormalizeHeaderKey(const std::string& s) {
   return result;
 }
 
-StringMap_t ParseHeaders(const char* headers, int32_t headers_length) {
-  enum State {
-    FINDING_KEY,
-    SKIPPING_WHITESPACE,
-    FINDING_VALUE,
-  };
-
-  StringMap_t result;
-  std::string key;
-  std::string value;
-
-  State state = FINDING_KEY;
-  const char* start = headers;
-  for (int i = 0; i < headers_length; ++i) {
-    switch (state) {
-      case FINDING_KEY:
-        if (headers[i] == ':') {
-          // Found key.
-          key.assign(start, &headers[i] - start);
-          key = NormalizeHeaderKey(key);
-          state = SKIPPING_WHITESPACE;
-        }
-        break;
-
-      case SKIPPING_WHITESPACE:
-        if (headers[i] == ' ') {
-          // Found whitespace, keep going...
-          break;
-        }
-
-        // Found a non-whitespace, mark this as the start of the value.
-        start = &headers[i];
-        state = FINDING_VALUE;
-        // Fallthrough to start processing value without incrementing i.
-
-      case FINDING_VALUE:
-        if (headers[i] == '\n') {
-          // Found value.
-          value.assign(start, &headers[i] - start);
-          result[key] = value;
-          start = &headers[i + 1];
-          state = FINDING_KEY;
-        }
-        break;
-    }
-  }
-
-  return result;
-}
-
-bool ParseContentLength(const StringMap_t& headers, size_t* content_length) {
-  StringMap_t::const_iterator iter = headers.find("Content-Length");
-  if (iter == headers.end())
-    return false;
-
-  *content_length = strtoul(iter->second.c_str(), NULL, 10);
-  return true;
-}
-
-bool ParseContentRange(const StringMap_t& headers, size_t* read_start,
-                       size_t* read_end, size_t* entity_length) {
-  StringMap_t::const_iterator iter = headers.find("Content-Range");
-  if (iter == headers.end())
-    return false;
-
-  // The key should look like "bytes ##-##/##" or "bytes ##-##/*". The last
-  // value is the entity length, which can potentially be * (i.e. unknown).
-  int read_start_int;
-  int read_end_int;
-  int entity_length_int;
-  int result = sscanf(iter->second.c_str(), "bytes %"SCNuS"-%"SCNuS"/%"SCNuS,
-                      &read_start_int, &read_end_int, &entity_length_int);
-
-  // The Content-Range header specifies an inclusive range: e.g. the first ten
-  // bytes is "bytes 0-9/*". Convert it to a half-open range by incrementing
-  // read_end.
-  if (result == 2) {
-    *read_start = read_start_int;
-    *read_end = read_end_int + 1;
-    *entity_length = 0;
-    return true;
-  } else if (result == 3) {
-    *read_start = read_start_int;
-    *read_end = read_end_int + 1;
-    *entity_length = entity_length_int;
-    return true;
-  }
-
-  return false;
-}
-
-}  // namespace
-
-
-class MountNodeHttp : public MountNode {
- public:
-  virtual int FSync();
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count);
-  virtual int GetStat(struct stat* stat);
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int FTruncate(off_t size);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-  virtual size_t GetSize();
-
-  void SetCachedSize(off_t size);
-
- protected:
-  MountNodeHttp(Mount* mount, const std::string& url, bool cache_content);
-
- private:
-  bool OpenUrl(const char* method,
-               StringMap_t* request_headers,
-               PP_Resource* out_loader,
-               PP_Resource* out_request,
-               PP_Resource* out_response,
-               int32_t* out_statuscode,
-               StringMap_t* out_response_headers);
-
-  int DownloadToCache();
-  int ReadPartialFromCache(size_t offs, void* buf, size_t count);
-  int DownloadPartial(size_t offs, void* buf, size_t count);
-  int DownloadToBuffer(PP_Resource loader, void* buf, size_t count);
-
-  std::string url_;
-  std::vector<char> buffer_;
-
-  bool cache_content_;
-  bool has_cached_size_;
-  std::vector<char> cached_data_;
-
-  friend class MountHttp;
-};
-
-void MountNodeHttp::SetCachedSize(off_t size) {
-  has_cached_size_ = true;
-  stat_.st_size = size;
-}
-
-int MountNodeHttp::FSync() {
-  errno = ENOSYS;
-  return -1;
-}
-
-int MountNodeHttp::GetDents(size_t offs, struct dirent* pdir, size_t count) {
-  errno = ENOSYS;
-  return -1;
-}
-
-int MountNodeHttp::GetStat(struct stat* stat) {
-  AutoLock lock(&lock_);
-
-  // Assume we need to 'HEAD' if we do not know the size, otherwise, assume
-  // that the information is constant.  We can add a timeout if needed.
-  MountHttp* mount = static_cast<MountHttp*>(mount_);
-  if (stat_.st_size == 0 || !mount->cache_stat_) {
-    StringMap_t headers;
-    PP_Resource loader;
-    PP_Resource request;
-    PP_Resource response;
-    int32_t statuscode;
-    StringMap_t response_headers;
-    if (!OpenUrl("HEAD", &headers, &loader, &request, &response, &statuscode,
-                &response_headers)) {
-      // errno is already set by OpenUrl.
-      return -1;
-    }
-
-    ScopedResource scoped_loader(mount_->ppapi(), loader);
-    ScopedResource scoped_request(mount_->ppapi(), request);
-    ScopedResource scoped_response(mount_->ppapi(), response);
-
-
-    size_t entity_length;
-    if (ParseContentLength(response_headers, &entity_length)) {
-      SetCachedSize(static_cast<off_t>(entity_length));
-    } else if (cache_content_ && !has_cached_size_) {
-      DownloadToCache();
-    } else {
-      // Don't use SetCachedSize here -- it is actually unknown.
-      stat_.st_size = 0;
-    }
-
-    stat_.st_atime = 0; // TODO(binji): Use "Last-Modified".
-    stat_.st_mtime = 0;
-    stat_.st_ctime = 0;
-  }
-
-  // Fill the stat structure if provided
-  if (stat) {
-    memcpy(stat, &stat_, sizeof(stat_));
-  }
-  return 0;
-}
-
-int MountNodeHttp::Read(size_t offs, void* buf, size_t count) {
-  AutoLock lock(&lock_);
-  if (cache_content_) {
-    if (cached_data_.empty()) {
-      if (DownloadToCache() < 0)
-        return -1;
-    }
-
-    return ReadPartialFromCache(offs, buf, count);
-  }
-
-  return DownloadPartial(offs, buf, count);
-}
-
-int MountNodeHttp::FTruncate(off_t size) {
-  errno = ENOSYS;
-  return -1;
-}
-
-int MountNodeHttp::Write(size_t offs, const void* buf, size_t count) {
-  // TODO(binji): support POST?
-  errno = ENOSYS;
-  return -1;
-}
-
-size_t MountNodeHttp::GetSize() {
-  // TODO(binji): This value should be cached properly; i.e. obey the caching
-  // headers returned by the server.
-  AutoLock lock(&lock_);
-  if (!has_cached_size_) {
-    // Even if DownloadToCache fails, the best result we can return is what
-    // was written to stat_.st_size.
-    if (cache_content_)
-      DownloadToCache();
-  }
-
-  return stat_.st_size;
-}
-
-MountNodeHttp::MountNodeHttp(Mount* mount, const std::string& url,
-                             bool cache_content)
-    : MountNode(mount),
-      url_(url),
-      cache_content_(cache_content),
-      has_cached_size_(false) {
-}
-
-bool MountNodeHttp::OpenUrl(const char* method,
-                           StringMap_t* request_headers,
-                           PP_Resource* out_loader,
-                           PP_Resource* out_request,
-                           PP_Resource* out_response,
-                           int32_t* out_statuscode,
-                           StringMap_t* out_response_headers) {
-  // Assume lock_ is already held.
-
-  PepperInterface* ppapi = mount_->ppapi();
-
-  MountHttp* mount_http = static_cast<MountHttp*>(mount_);
-  ScopedResource request(ppapi,
-                         mount_http->MakeUrlRequestInfo(url_, method,
-                                                        request_headers));
-  if (!request.pp_resource()) {
-    errno = EINVAL;
-    return false;
-  }
-
-  URLLoaderInterface* loader_interface = ppapi->GetURLLoaderInterface();
-  URLResponseInfoInterface* response_interface =
-      ppapi->GetURLResponseInfoInterface();
-  VarInterface* var_interface = ppapi->GetVarInterface();
-
-  ScopedResource loader(ppapi, loader_interface->Create(ppapi->GetInstance()));
-  if (!loader.pp_resource()) {
-    errno = EINVAL;
-    return false;
-  }
-
-  int32_t result = loader_interface->Open(
-      loader.pp_resource(), request.pp_resource(), PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return false;
-  }
-
-  ScopedResource response(
-      ppapi,
-      loader_interface->GetResponseInfo(loader.pp_resource()));
-  if (!response.pp_resource()) {
-    errno = EINVAL;
-    return false;
-  }
-
-  // Get response statuscode.
-  PP_Var statuscode = response_interface->GetProperty(
-      response.pp_resource(),
-      PP_URLRESPONSEPROPERTY_STATUSCODE);
-
-  if (statuscode.type != PP_VARTYPE_INT32) {
-    errno = EINVAL;
-    return false;
-  }
-
-  *out_statuscode = statuscode.value.as_int;
-
-  // Only accept OK or Partial Content.
-  if (*out_statuscode != STATUSCODE_OK &&
-      *out_statuscode != STATUSCODE_PARTIAL_CONTENT) {
-    errno = EINVAL;
-    return false;
-  }
-
-  // Get response headers.
-  PP_Var response_headers_var = response_interface->GetProperty(
-      response.pp_resource(),
-      PP_URLRESPONSEPROPERTY_HEADERS);
-
-  uint32_t response_headers_length;
-  const char* response_headers_str = var_interface->VarToUtf8(
-      response_headers_var,
-      &response_headers_length);
-
-  *out_loader = loader.Release();
-  *out_request = request.Release();
-  *out_response = response.Release();
-  *out_response_headers = ParseHeaders(response_headers_str,
-                                       response_headers_length);
-
-  return true;
-}
-
-int MountNodeHttp::DownloadToCache() {
-  StringMap_t headers;
-  PP_Resource loader;
-  PP_Resource request;
-  PP_Resource response;
-  int32_t statuscode;
-  StringMap_t response_headers;
-  if (!OpenUrl("GET", &headers, &loader, &request, &response, &statuscode,
-               &response_headers)) {
-    // errno is already set by OpenUrl.
-    return -1;
-  }
-
-  PepperInterface* ppapi = mount_->ppapi();
-  ScopedResource scoped_loader(ppapi, loader);
-  ScopedResource scoped_request(ppapi, request);
-  ScopedResource scoped_response(ppapi, response);
-
-  size_t content_length = 0;
-  if (ParseContentLength(response_headers, &content_length)) {
-    cached_data_.resize(content_length);
-    int real_size = DownloadToBuffer(loader, cached_data_.data(),
-                                     content_length);
-    if (real_size < 0)
-      return -1;
-
-    SetCachedSize(real_size);
-    cached_data_.resize(real_size);
-    return real_size;
-  }
-
-  // We don't know how big the file is. Read in chunks.
-  cached_data_.resize(MAX_READ_BUFFER_SIZE);
-  size_t total_bytes_read = 0;
-  size_t bytes_to_read = MAX_READ_BUFFER_SIZE;
-  while (true) {
-    char* buf = cached_data_.data() + total_bytes_read;
-    int bytes_read = DownloadToBuffer(loader, buf, bytes_to_read);
-    if (bytes_read < 0)
-      return -1;
-
-    total_bytes_read += bytes_read;
-
-    if (bytes_read < bytes_to_read) {
-      SetCachedSize(total_bytes_read);
-      cached_data_.resize(total_bytes_read);
-      return total_bytes_read;
-    }
-
-    cached_data_.resize(total_bytes_read + bytes_to_read);
-  }
-}
-
-int MountNodeHttp::ReadPartialFromCache(size_t offs, void* buf, size_t count) {
-  if (offs > cached_data_.size()) {
-    errno = EINVAL;
-    return -1;
-  }
-
-  count = std::min(count, cached_data_.size() - offs);
-  memcpy(buf, &cached_data_.data()[offs], count);
-  return count;
-}
-
-int MountNodeHttp::DownloadPartial(size_t offs, void* buf, size_t count) {
-  StringMap_t headers;
-
-  char buffer[100];
-  // Range request is inclusive: 0-99 returns 100 bytes.
-  snprintf(&buffer[0], sizeof(buffer), "bytes=%"PRIuS"-%"PRIuS,
-           offs, offs + count - 1);
-  headers["Range"] = buffer;
-
-  PP_Resource loader;
-  PP_Resource request;
-  PP_Resource response;
-  int32_t statuscode;
-  StringMap_t response_headers;
-  if (!OpenUrl("GET", &headers, &loader, &request, &response, &statuscode,
-               &response_headers)) {
-    // errno is already set by OpenUrl.
-    return -1;
-  }
-
-  PepperInterface* ppapi = mount_->ppapi();
-  ScopedResource scoped_loader(ppapi, loader);
-  ScopedResource scoped_request(ppapi, request);
-  ScopedResource scoped_response(ppapi, response);
-
-  size_t read_start = 0;
-  if (statuscode == STATUSCODE_OK) {
-    // No partial result, read everything starting from the part we care about.
-    size_t content_length;
-    if (ParseContentLength(response_headers, &content_length)) {
-      if (offs >= content_length) {
-        errno = EINVAL;
-        return 0;
-      }
+Error MountHttp::Open(const Path& path, int mode, MountNode** out_node) {
+  *out_node = NULL;
 
-      // Clamp count, if trying to read past the end of the file.
-      if (offs + count > content_length) {
-        count = content_length - offs;
-      }
-    }
-  } else if (statuscode == STATUSCODE_PARTIAL_CONTENT) {
-    // Determine from the headers where we are reading.
-    size_t read_end;
-    size_t entity_length;
-    if (ParseContentRange(response_headers, &read_start, &read_end,
-                          &entity_length)) {
-      if (read_start > offs || read_start > read_end) {
-        // If this error occurs, the server is returning bogus values.
-        errno = EINVAL;
-        return -1;
-      }
+  assert(url_root_.empty() || url_root_[url_root_.length() - 1] == '/');
 
-      // Clamp count, if trying to read past the end of the file.
-      count = std::min(read_end - read_start, count);
-    } else {
-      // Partial Content without Content-Range. Assume that the server gave us
-      // exactly what we asked for. This can happen even when the server
-      // returns 200 -- the cache may return 206 in this case, but not modify
-      // the headers.
-      read_start = offs;
-    }
+  NodeMap_t::iterator iter = node_cache_.find(path.Join());
+  if (iter != node_cache_.end()) {
+    *out_node = iter->second;
+    return 0;
   }
 
-  if (read_start < offs) {
-    // We aren't yet at the location where we want to start reading. Read into
-    // our dummy buffer until then.
-    size_t bytes_to_read = offs - read_start;
-    if (buffer_.size() < bytes_to_read)
-      buffer_.resize(std::min(bytes_to_read, MAX_READ_BUFFER_SIZE));
-
-    while (bytes_to_read > 0) {
-      int32_t bytes_read = DownloadToBuffer(loader, buffer_.data(),
-                                            buffer_.size());
-      if (bytes_read < 0)
-        return -1;
+  // If we can't find the node in the cache, create it
+  std::string url = url_root_ + (path.IsAbsolute() ? path.Range(1, path.Size())
+                                                   : path.Join());
 
-      bytes_to_read -= bytes_read;
-    }
+  MountNodeHttp* node = new MountNodeHttp(this, url, cache_content_);
+  Error error = node->Init(mode);
+  if (error) {
+    node->Release();
+    return error;
   }
 
-  return DownloadToBuffer(loader, buf, count);
-}
-
-int MountNodeHttp::DownloadToBuffer(PP_Resource loader, void* buf,
-                                    size_t count) {
-  PepperInterface* ppapi = mount_->ppapi();
-  URLLoaderInterface* loader_interface = ppapi->GetURLLoaderInterface();
-
-  char* out_buffer = static_cast<char*>(buf);
-  size_t bytes_to_read = count;
-  while (bytes_to_read > 0) {
-    int32_t bytes_read = loader_interface->ReadResponseBody(
-        loader, out_buffer, bytes_to_read, PP_BlockUntilComplete());
-
-    if (bytes_read == 0) {
-      // This is not an error -- it may just be that we were trying to read
-      // more data than exists.
-      return count - bytes_to_read;
-    }
-
-    if (bytes_read < 0) {
-      errno = PPErrorToErrno(bytes_read);
-      return -1;
-    }
-
-    assert(bytes_read <= bytes_to_read);
-    bytes_to_read -= bytes_read;
-    out_buffer += bytes_read;
+  error = node->GetStat(NULL);
+  if (error) {
+    node->Release();
+    return error;
   }
 
-  return count;
-}
-
-MountNode *MountHttp::Open(const Path& path, int mode) {
-  assert(url_root_.empty() || url_root_[url_root_.length() - 1] == '/');
-
-  NodeMap_t::iterator iter = node_cache_.find(path.Join());
-  if (iter != node_cache_.end()) {
-    return iter->second;
+  MountNodeDir* parent;
+  error = FindOrCreateDir(path.Parent(), &parent);
+  if (error) {
+    node->Release();
+    return error;
   }
 
-  // If we can't find the node in the cache, create it
-  std::string url = url_root_ + (path.IsAbsolute() ?
-      path.Range(1, path.Size()) :
-      path.Join());
-
-  MountNodeHttp* node = new MountNodeHttp(this, url, cache_content_);
-  if (!node->Init(mode) || (0 != node->GetStat(NULL))) {
+  error = parent->AddChild(path.Basename(), node);
+  if (error) {
     node->Release();
-    return NULL;
+    return error;
   }
 
-  MountNodeDir* parent = FindOrCreateDir(path.Parent());
   node_cache_[path.Join()] = node;
-  parent->AddChild(path.Basename(), node);
-  return node;
-}
 
-int MountHttp::Unlink(const Path& path) {
-  errno = ENOSYS;
-  return -1;
+  *out_node = node;
+  return 0;
 }
 
-int MountHttp::Mkdir(const Path& path, int permissions) {
-  errno = ENOSYS;
-  return -1;
-}
+Error MountHttp::Unlink(const Path& path) { return ENOSYS; }
 
-int MountHttp::Rmdir(const Path& path) {
-  errno = ENOSYS;
-  return -1;
-}
+Error MountHttp::Mkdir(const Path& path, int permissions) { return ENOSYS; }
 
-int MountHttp::Remove(const Path& path) {
-  errno = ENOSYS;
-  return -1;
-}
+Error MountHttp::Rmdir(const Path& path) { return ENOSYS; }
+
+Error MountHttp::Remove(const Path& path) { return ENOSYS; }
 
-PP_Resource MountHttp::MakeUrlRequestInfo(
-    const std::string& url,
-    const char* method,
-    StringMap_t* additional_headers) {
+PP_Resource MountHttp::MakeUrlRequestInfo(const std::string& url,
+                                          const char* method,
+                                          StringMap_t* additional_headers) {
   URLRequestInfoInterface* interface = ppapi_->GetURLRequestInfoInterface();
   VarInterface* var_interface = ppapi_->GetVarInterface();
 
@@ -618,21 +119,23 @@ PP_Resource MountHttp::MakeUrlRequestInfo(
   if (!request_info)
     return 0;
 
-  interface->SetProperty(
-      request_info, PP_URLREQUESTPROPERTY_URL,
-      var_interface->VarFromUtf8(url.c_str(), url.length()));
-  interface->SetProperty(request_info, PP_URLREQUESTPROPERTY_METHOD,
+  interface->SetProperty(request_info,
+                         PP_URLREQUESTPROPERTY_URL,
+                         var_interface->VarFromUtf8(url.c_str(), url.length()));
+  interface->SetProperty(request_info,
+                         PP_URLREQUESTPROPERTY_METHOD,
                          var_interface->VarFromUtf8(method, strlen(method)));
   interface->SetProperty(request_info,
                          PP_URLREQUESTPROPERTY_ALLOWCROSSORIGINREQUESTS,
                          PP_MakeBool(allow_cors_ ? PP_TRUE : PP_FALSE));
-  interface->SetProperty(request_info, PP_URLREQUESTPROPERTY_ALLOWCREDENTIALS,
+  interface->SetProperty(request_info,
+                         PP_URLREQUESTPROPERTY_ALLOWCREDENTIALS,
                          PP_MakeBool(allow_credentials_ ? PP_TRUE : PP_FALSE));
 
   // Merge the mount headers with the request headers. If the field is already
   // set it |additional_headers|, don't use the one from headers_.
   for (StringMap_t::iterator iter = headers_.begin(); iter != headers_.end();
-      ++iter) {
+       ++iter) {
     const std::string& key = NormalizeHeaderKey(iter->first);
     if (additional_headers->find(key) == additional_headers->end()) {
       additional_headers->insert(std::make_pair(key, iter->second));
@@ -642,12 +145,14 @@ PP_Resource MountHttp::MakeUrlRequestInfo(
   // Join the headers into one string.
   std::string headers;
   for (StringMap_t::iterator iter = additional_headers->begin();
-      iter != additional_headers->end(); ++iter) {
+       iter != additional_headers->end();
+       ++iter) {
     headers += iter->first + ": " + iter->second + '\n';
   }
 
   interface->SetProperty(
-      request_info, PP_URLREQUESTPROPERTY_HEADERS,
+      request_info,
+      PP_URLREQUESTPROPERTY_HEADERS,
       var_interface->VarFromUtf8(headers.c_str(), headers.length()));
 
   return request_info;
@@ -657,12 +162,12 @@ MountHttp::MountHttp()
     : allow_cors_(false),
       allow_credentials_(false),
       cache_stat_(true),
-      cache_content_(true) {
-}
+      cache_content_(true) {}
 
-bool MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
-  if (!Mount::Init(dev, args, ppapi))
-    return false;
+Error MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+  Error error = Mount::Init(dev, args, ppapi);
+  if (error)
+    return error;
 
   // Parse mount args.
   for (StringMap_t::iterator iter = args.begin(); iter != args.end(); ++iter) {
@@ -674,11 +179,18 @@ bool MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
         url_root_ += '/';
       }
     } else if (iter->first == "manifest") {
-      char *text = LoadManifest(iter->second);
-      if (text != NULL) {
-        ParseManifest(text);
+      char* text;
+      error = LoadManifest(iter->second, &text);
+      if (error)
+        return error;
+
+      error = ParseManifest(text);
+      if (error) {
         delete[] text;
+        return error;
       }
+
+      delete[] text;
     } else if (iter->first == "allow_cross_origin_requests") {
       allow_cors_ = iter->second == "true";
     } else if (iter->first == "allow_credentials") {
@@ -693,34 +205,53 @@ bool MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
     }
   }
 
-  return true;
+  return 0;
 }
 
-void MountHttp::Destroy() {
-}
+void MountHttp::Destroy() {}
+
+Error MountHttp::FindOrCreateDir(const Path& path, MountNodeDir** out_node) {
+  *out_node = NULL;
 
-MountNodeDir* MountHttp::FindOrCreateDir(const Path& path) {
   std::string strpath = path.Join();
   NodeMap_t::iterator iter = node_cache_.find(strpath);
   if (iter != node_cache_.end()) {
-    return static_cast<MountNodeDir*>(iter->second);
+    *out_node = static_cast<MountNodeDir*>(iter->second);
+    return 0;
   }
 
-  // If the node does not exist, create it, and add it to the node cache
+  // If the node does not exist, create it.
   MountNodeDir* node = new MountNodeDir(this);
-  node->Init(S_IREAD);
-  node_cache_[strpath] = node;
+  Error error = node->Init(S_IREAD);
+  if (error) {
+    node->Release();
+    return error;
+  }
 
   // If not the root node, find the parent node and add it to the parent
   if (!path.Top()) {
-    MountNodeDir* parent = FindOrCreateDir(path.Parent());
-    parent->AddChild(path.Basename(), node);
+    MountNodeDir* parent;
+    error = FindOrCreateDir(path.Parent(), &parent);
+    if (error) {
+      node->Release();
+      return error;
+    }
+
+    error = parent->AddChild(path.Basename(), node);
+    if (error) {
+      node->Release();
+      return error;
+    }
   }
 
-  return node;
+  // Add it to the node cache.
+  node_cache_[strpath] = node;
+
+  *out_node = node;
+  return 0;
 }
 
-bool MountHttp::ParseManifest(char *text) {
+Error MountHttp::ParseManifest(char* text) {
   StringList_t lines;
   SplitString(text, "\n", &lines);
 
@@ -741,62 +272,102 @@ bool MountHttp::ParseManifest(char *text) {
       // Ignore EXEC bit
       int mode = S_IFREG;
       switch (modestr[0]) {
-        case '-': mode = S_IFREG; break;
-        case 'c': mode = S_IFCHR; break;
+        case '-':
+          mode = S_IFREG;
+          break;
+        case 'c':
+          mode = S_IFCHR;
+          break;
         default:
           fprintf(stderr, "Unable to parse type %s for %s.\n", modestr, name);
-          return false;
+          return EINVAL;
       }
 
       switch (modestr[1]) {
-        case '-': break;
-        case 'r': mode |= S_IREAD; break;
+        case '-':
+          break;
+        case 'r':
+          mode |= S_IREAD;
+          break;
         default:
           fprintf(stderr, "Unable to parse read %s for %s.\n", modestr, name);
-          return false;
+          return EINVAL;
       }
 
       switch (modestr[2]) {
-        case '-': break;
-        case 'w': mode |= S_IWRITE; break;
+        case '-':
+          break;
+        case 'w':
+          mode |= S_IWRITE;
+          break;
         default:
           fprintf(stderr, "Unable to parse write %s for %s.\n", modestr, name);
-          return false;
+          return EINVAL;
       }
 
       Path path(name);
-      std::string url = url_root_ + (path.IsAbsolute() ?
-          path.Range(1, path.Size()) :
-          path.Join());
+      std::string url =
+          url_root_ +
+          (path.IsAbsolute() ? path.Range(1, path.Size()) : path.Join());
 
       MountNodeHttp* node = new MountNodeHttp(this, url, cache_content_);
-      node->Init(mode);
+      Error error = node->Init(mode);
+      if (error) {
+        node->Release();
+        return error;
+      }
+
       node->SetCachedSize(atoi(lenstr));
 
-      MountNodeDir* dir_node = FindOrCreateDir(path.Parent());
-      dir_node->AddChild(path.Basename(), node);
+      MountNodeDir* dir_node;
+      error = FindOrCreateDir(path.Parent(), &dir_node);
+      if (error) {
+        node->Release();
+        return error;
+      }
+
+      error = dir_node->AddChild(path.Basename(), node);
+      if (error) {
+        node->Release();
+        return error;
+      }
 
       std::string pname = path.Join();
       node_cache_[pname] = node;
     }
   }
 
-  return true;
+  return 0;
 }
 
-char *MountHttp::LoadManifest(const std::string& manifest_name) {
+Error MountHttp::LoadManifest(const std::string& manifest_name,
+                              char** out_manifest) {
   Path manifest_path(manifest_name);
-  MountNode* manifest_node = Open(manifest_path, O_RDONLY);
+  MountNode* manifest_node = NULL;
+  *out_manifest = NULL;
 
-  if (manifest_node) {
-    char *text = new char[manifest_node->GetSize() + 1];
-    off_t len = manifest_node->Read(0, text, manifest_node->GetSize());
+  int error = Open(manifest_path, O_RDONLY, &manifest_node);
+  if (error)
+    return error;
+
+  size_t size;
+  error = manifest_node->GetSize(&size);
+  if (error) {
     manifest_node->Release();
+    return error;
+  }
 
-    text[len] = 0;
-    return text;
+  char* text = new char[size + 1];
+  int len;
+  error = manifest_node->Read(0, text, size, &len);
+  if (error) {
+    manifest_node->Release();
+    return error;
   }
 
-  fprintf(stderr, "Could not open manifest: %s\n", manifest_name.c_str());
-  return NULL;
+  manifest_node->Release();
+  text[len] = 0;
+
+  *out_manifest = text;
+  return 0;
 }