Add GetAppDataPath() to get application-specific data path for storing files for the user.

Adds shell32 linker requirement for Windows.

PiperOrigin-RevId: 313681313

Author: jonsimantov

database/CMakeLists.txt

@@ -139,8 +139,18 @@ elseif(IOS)
   set(database_platform_SRCS
       "${ios_SRCS}")
 else()
+  # Add platform-specific util files.
+  if(MSVC)
+    set(desktop_extra_SRCS src/desktop/util_desktop_windows.cc)
+  elseif(APPLE)
+    set(desktop_extra_SRCS src/desktop/util_desktop_macos.mm)
+  else()
+    # Linux
+    set(desktop_extra_SRCS src/desktop/util_desktop_linux.cc)
+  endif()
   set(database_platform_SRCS
-      "${desktop_SRCS}")
+        "${desktop_SRCS}"
+        "${desktop_extra_SRCS}")
 endif()
 
 if(ANDROID OR IOS)

database/src/desktop/util_desktop.h

@@ -347,6 +347,12 @@ std::string WireProtocolPathToString(const Path& path);
 // NOTE: Don't change this unless you're changing the wire protocol!
 Variant GetWireProtocolParams(const QueryParams& query_params);
 
+// Get a local path that you can use for storing app-specific files.
+// This is platform-specific. If it returns an empty string, it was
+// unable to find a proper path and you can just use the current directory
+// or whatever.
+std::string GetAppDataPath(const char* app_name, bool should_create = true);
+
 }  // namespace internal
 }  // namespace database
 }  // namespace firebase

database/src/desktop/util_desktop_linux.cc

@@ -0,0 +1,74 @@
+// Copyright 2017 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <dirent.h>
+#include <pwd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "database/src/desktop/util_desktop.h"
+
+namespace firebase {
+namespace database {
+namespace internal {
+
+std::string GetAppDataPath(const char* app_name, bool should_create) {
+  // On Linux, use XDG data home, usually $HOME/.local/share/$app_name, or user
+  // home directory otherwise.
+
+  const char* xdg_data_home = getenv("XDG_DATA_HOME");
+  if (xdg_data_home) {
+    // Assume that this directory already exists.
+    return std::string(xdg_data_home);
+  }
+  std::string home_directory = "";
+
+  const char* home = getenv("HOME");
+  if (home) {
+    home_directory = std::string(home);
+  } else {
+    // Get home directory from user info.
+    passwd pwd;
+    passwd* result;
+    auto buffer_size = static_cast<size_t>(sysconf(_SC_GETPW_R_SIZE_MAX));
+    std::string buffer(buffer_size, '\0');
+    uid_t uid = getuid();
+    int rc;
+    do {
+      rc = getpwuid_r(uid, &pwd, &buffer[0], buffer_size, &result);
+    } while (rc == EINTR);
+    if (rc == 0) {
+      home_directory = std::string(pwd.pw_dir);
+    }
+  }
+  if (home_directory.empty()) return "";
+
+  // Make sure home/.local/share exists, ignore "already exists" errors making
+  // these directories.
+  if (should_create) {
+    int retval;
+    retval = mkdir((home_directory + "/.local").c_str(), 0700);
+    if (retval != 0 && errno != EEXIST) return "";
+    retval = mkdir((home_directory + "/.local/share").c_str(), 0700);
+    if (retval != 0 && errno != EEXIST) return "";
+    retval = mkdir((home_directory + "/.local/share" + app_name).c_str(), 0700);
+    if (retval != 0 && errno != EEXIST) return "";
+  }
+  return (home_directory + "/.local/share" + app_name);
+}
+
+}  // namespace internal
+}  // namespace database
+}  // namespace firebase

database/src/desktop/util_desktop_macos.mm

@@ -0,0 +1,41 @@
+// Copyright 2017 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include "database/src/desktop/util_desktop.h"
+
+namespace firebase {
+namespace database {
+namespace internal {
+
+std::string GetAppDataPath(const char* app_name, bool should_create) {
+  NSArray<NSString*>* directories =
+      NSSearchPathForDirectoriesInDomains(NSApplicationSupportDirectory, NSUserDomainMask, YES);
+  std::string path = directories[0].UTF8String;
+  if (should_create) {
+    int retval;
+    retval = mkdir(path.c_str(), 0700);
+    if (retval != 0 && errno != EEXIST) return "";
+    retval = mkdir((path + "/" + app_name).c_str(), 0700);
+    if (retval != 0 && errno != EEXIST) return "";
+  }
+  return path + "/" + app_name;
+}
+
+}  // namespace internal
+}  // namespace database
+}  // namespace firebase

database/src/desktop/util_desktop_windows.cc

@@ -0,0 +1,58 @@
+// Copyright 2017 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <direct.h>
+#include <shlobj.h>
+#include <stringapiset.h>
+
+#include <iostream>
+#include <string>
+
+#include "app/src/log.h"
+#include "database/src/desktop/util_desktop.h"
+
+namespace firebase {
+namespace database {
+namespace internal {
+
+static std::string utf8_encode(const std::wstring& wstr) {
+  if (wstr.empty()) return std::string();
+  int size_needed = WideCharToMultiByte(CP_UTF8, 0, &wstr[0], (int)wstr.size(),
+                                        NULL, 0, NULL, NULL);
+  std::string strTo(size_needed, 0);
+  WideCharToMultiByte(CP_UTF8, 0, &wstr[0], (int)wstr.size(), &strTo[0],
+                      size_needed, NULL, NULL);
+  return strTo;
+}
+
+std::string GetAppDataPath(const char* app_name, bool should_create) {
+  wchar_t* pwstr = nullptr;
+  HRESULT result = SHGetKnownFolderPath(FOLDERID_LocalAppData, 0, NULL, &pwstr);
+  if (result != S_OK) {
+    return "";
+  }
+  std::wstring wstr(pwstr);
+  CoTaskMemFree(static_cast<void*>(pwstr));
+  std::string dir = utf8_encode(wstr);
+  if (dir == "") return "";
+  if (should_create) {
+    int retval = _mkdir((dir + "\\" + app_name).c_str());
+    if (retval != 0 && errno != EEXIST) return "";
+  }
+  return dir + "\\" + app_name;
+}
+
+}  // namespace internal
+}  // namespace database
+}  // namespace firebase