Merge RFC4 (#1865)

This commit is the result of the squashing of rfc4_dev branch in a single
commit. It implements mostly RFC 4 related work.

* Grid handling:
  - remove obsolete and presumably unfinished implementation of grid catalog functionality
  - all grid functionality is in grids.cpp/.hpp
  - vertical and horizontal grid shift: rework to no longer load whole grid into memory
  - remove hgrids and vgrids member from PJ structure, and store them in hgridshift/vgridshift/deformation structures
  - build systems: add optional libtiff dependency. Must be explicitly disabled if not desired
  - add support for horizontal and vertical grids in GeoTIFF, if libtiff is available
  - add GenericShiftGridSet and GenericShiftGrid classes, relying on TIFF grids, that can be used for generic purpose grid-based adjustment
  - add a +proj=xyzgridshift method to perform geocentric translation by grid. Used for French NTF to RGF93 transformation using gr3df97a.tif grid
  - deformation: add support for +grids= for GeoTIFF grids
  - horizontal grid shift: fix failures on points slightly outside a subgrid (fixes #209)

* File management:
  - add a filemanager.cpp/.hpp to deal with file related work
  - test for legacy proj_api.h fileapi
  - proj.h: add proj_context_set_fileapi() and proj_context_set_sqlite3_vfs_name() (fixes #866)
  - add capability to read resource files from the user writable directory

* Network access:
  - build systems: add optional curl dependency
  - add a curl-based default implementation for network related functionality
  - proj.h: add C API to control network functionality, and optionaly provide network callbacks
  - add data/proj.ini with default settings
  - add a SQLite3 local cache of downloaded chunks
  - add proj_is_download_needed() and proj_download_file()

* Use Win32 Unicode APIs and expect all strings to be UTF-8 (fixes #1765)
  For backward compatibility, if PROJ_LIB content is found to be not UTF-8 or
  pointing to a non existing directory, then an attempt at interpretating it
  in the ANSI page encoding is done.
  proj_context_set_search_paths() now assumes strings to be in UTF-8, and
  functions returning paths will also return values in UTF-8.

1 files changed, 100 insertions, 0 deletions

diff --git a/src/filemanager.hpp b/src/filemanager.hpp
new file mode 100644
index 00000000..554bd325
--- /dev/null
+++ b/src/filemanager.hpp
@@ -0,0 +1,100 @@
+/******************************************************************************
+ * Project:  PROJ
+ * Purpose:  File manager
+ * Author:   Even Rouault, <even.rouault at spatialys.com>
+ *
+ ******************************************************************************
+ * Copyright (c) 2019, Even Rouault, <even.rouault at spatialys.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *****************************************************************************/
+
+#ifndef FILEMANAGER_HPP_INCLUDED
+#define FILEMANAGER_HPP_INCLUDED
+
+#include <memory>
+
+#include "proj.h"
+#include "proj/util.hpp"
+
+//! @cond Doxygen_Suppress
+
+NS_PROJ_START
+
+class File;
+
+enum class FileAccess {
+    READ_ONLY,   // "rb"
+    READ_UPDATE, // "r+b"
+    CREATE,      // "w+b"
+};
+
+class FileManager {
+  private:
+    FileManager() = delete;
+
+  public:
+    // "Low-level" interface.
+    static std::unique_ptr<File> open(PJ_CONTEXT *ctx, const char *filename,
+                                      FileAccess access);
+    static bool exists(PJ_CONTEXT *ctx, const char *filename);
+    static bool mkdir(PJ_CONTEXT *ctx, const char *filename);
+    static bool unlink(PJ_CONTEXT *ctx, const char *filename);
+    static bool rename(PJ_CONTEXT *ctx, const char *oldPath,
+                       const char *newPath);
+    static std::string getProjLibEnvVar(PJ_CONTEXT *ctx);
+
+    // "High-level" interface, honoring PROJ_LIB and the like.
+    static std::unique_ptr<File> open_resource_file(PJ_CONTEXT *ctx,
+                                                    const char *name);
+
+    static void fillDefaultNetworkInterface(PJ_CONTEXT *ctx);
+
+    static void clearMemoryCache();
+};
+
+// ---------------------------------------------------------------------------
+
+class File {
+  protected:
+    std::string name_;
+    explicit File(const std::string &name);
+
+  public:
+    virtual ~File();
+    virtual size_t read(void *buffer, size_t sizeBytes) = 0;
+    virtual size_t write(const void *buffer, size_t sizeBytes) = 0;
+    virtual bool seek(unsigned long long offset, int whence = SEEK_SET) = 0;
+    virtual unsigned long long tell() = 0;
+    virtual void reassign_context(PJ_CONTEXT *ctx) = 0;
+    virtual bool hasChanged() const = 0;
+
+    const std::string &name() const { return name_; }
+};
+
+// ---------------------------------------------------------------------------
+
+std::unique_ptr<File> pj_network_file_open(PJ_CONTEXT *ctx,
+                                           const char *filename);
+
+NS_PROJ_END
+
+//! @endcond Doxygen_Suppress
+
+#endif // FILEMANAGER_HPP_INCLUDED