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, 7 insertions, 29 deletions

diff --git a/src/ctx.cpp b/src/ctx.cpp
index bcb6e1cc..6172b3c8 100644
--- a/src/ctx.cpp
+++ b/src/ctx.cpp
@@ -33,6 +33,7 @@
 
 #include "proj_experimental.h"
 #include "proj_internal.h"
+#include "filemanager.hpp"
 
 /************************************************************************/
 /*                             pj_get_ctx()                             */
@@ -60,9 +61,9 @@ void pj_set_ctx( projPJ pj, projCtx ctx )
     if (pj==nullptr)
         return;
     pj->ctx = ctx;
-    if( pj->is_pipeline )
+    if( pj->reassign_context )
     {
-        pj_pipeline_assign_context_to_steps(pj, ctx);
+        pj->reassign_context(pj, ctx);
     }
     for( const auto &alt: pj->alternativeCoordinateOperations )
     {
@@ -95,7 +96,8 @@ projCtx_t projCtx_t::createDefault()
     projCtx_t ctx;
     ctx.debug_level = PJ_LOG_NONE;
     ctx.logger = pj_stderr_logger;
-    ctx.fileapi = pj_get_default_fileapi();
+    ctx.fileapi_legacy = pj_get_default_fileapi();
+    NS_PROJ::FileManager::fillDefaultNetworkInterface(&ctx);
 
     if( getenv("PROJ_DEBUG") != nullptr )
     {
@@ -133,12 +135,13 @@ projCtx_t::projCtx_t(const projCtx_t& other)
     debug_level = other.debug_level;
     logger = other.logger;
     logger_app_data = other.logger_app_data;
-    fileapi = other.fileapi;
+    fileapi_legacy = other.fileapi_legacy;
     epsg_file_exists = other.epsg_file_exists;
     set_search_paths(other.search_paths);
     file_finder = other.file_finder;
     file_finder_legacy = other.file_finder_legacy;
     file_finder_user_data = other.file_finder_user_data;
+    networking = other.networking;
 }
 
 /************************************************************************/
@@ -258,28 +261,3 @@ void *pj_ctx_get_app_data( projCtx ctx )
         return nullptr;
     return ctx->logger_app_data;
 }
-
-/************************************************************************/
-/*                         pj_ctx_set_fileapi()                         */
-/************************************************************************/
-
-void pj_ctx_set_fileapi( projCtx ctx, projFileAPI *fileapi )
-
-{
-    if (nullptr==ctx)
-        return;
-    ctx->fileapi = fileapi;
-}
-
-/************************************************************************/
-/*                         pj_ctx_get_fileapi()                         */
-/************************************************************************/
-
-projFileAPI *pj_ctx_get_fileapi( projCtx ctx )
-
-{
-    if (nullptr==ctx)
-        return nullptr;
-    return ctx->fileapi;
-}
-