Network: automatically use CDN resources when local resources not available, and networking enabled

3 files changed, 29 insertions, 12 deletions

diff --git a/include/proj/coordinateoperation.hpp b/include/proj/coordinateoperation.hpp
index 55bc28a0..bee3eff2 100644
--- a/include/proj/coordinateoperation.hpp
+++ b/include/proj/coordinateoperation.hpp
@@ -144,10 +144,12 @@ class PROJ_GCC_DLL CoordinateOperation : public common::ObjectUsage,
 
     /** \brief Return grids needed by an operation. */
     PROJ_DLL virtual std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const = 0;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const = 0;
 
     PROJ_DLL bool
-    isPROJInstantiable(const io::DatabaseContextPtr &databaseContext) const;
+    isPROJInstantiable(const io::DatabaseContextPtr &databaseContext,
+                       bool considerKnownGridsAsAvailable) const;
 
     PROJ_DLL bool hasBallparkTransformation() const;
 
@@ -595,7 +597,8 @@ class PROJ_GCC_DLL SingleOperation : virtual public CoordinateOperation {
             std::vector<metadata::PositionalAccuracyNNPtr>());
 
     PROJ_DLL std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override;
 
     PROJ_DLL std::list<std::string> validateParameters() const;
 
@@ -1672,7 +1675,8 @@ class PROJ_GCC_DLL ConcatenatedOperation final : public CoordinateOperation {
         bool checkExtent); // throw InvalidOperation
 
     PROJ_DLL std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override;
 
     PROJ_PRIVATE :
 
@@ -1801,6 +1805,12 @@ class PROJ_GCC_DLL CoordinateOperationContext {
         /** Ignore grid availability at all. Results will be presented as if
          * all grids were available. */
         IGNORE_GRID_AVAILABILITY,
+
+        /** Results will be presented as if grids known to PROJ (that is
+        * registered in the grid_alternatives table of its database) were
+        * available. Used typically when networking is enabled.
+        */
+        KNOWN_AVAILABLE,
     };
 
     PROJ_DLL void setGridAvailabilityUse(GridAvailabilityUse use);
diff --git a/include/proj/internal/coordinateoperation_internal.hpp b/include/proj/internal/coordinateoperation_internal.hpp
index 7ae2cd78..921021ec 100644
--- a/include/proj/internal/coordinateoperation_internal.hpp
+++ b/include/proj/internal/coordinateoperation_internal.hpp
@@ -177,8 +177,10 @@ class InverseConversion : public Conversion, public InverseCoordinateOperation {
     // 'osgeo::proj::operation::SingleOperation::osgeo::proj::operation::SingleOperation::gridsNeeded'
     // via dominance
     std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override {
-        return SingleOperation::gridsNeeded(databaseContext);
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override {
+        return SingleOperation::gridsNeeded(databaseContext,
+                                            considerKnownGridsAsAvailable);
     }
 #endif
 
@@ -227,8 +229,10 @@ class InverseTransformation : public Transformation,
     // 'osgeo::proj::operation::SingleOperation::osgeo::proj::operation::SingleOperation::gridsNeeded'
     // via dominance
     std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override {
-        return SingleOperation::gridsNeeded(databaseContext);
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override {
+        return SingleOperation::gridsNeeded(databaseContext,
+                                            considerKnownGridsAsAvailable);
     }
 #endif
 
@@ -269,7 +273,8 @@ class PROJBasedOperation : public SingleOperation {
            bool hasRoughTransformation);
 
     std::set<GridDescription>
-    gridsNeeded(const io::DatabaseContextPtr &databaseContext) const override;
+    gridsNeeded(const io::DatabaseContextPtr &databaseContext,
+                bool considerKnownGridsAsAvailable) const override;
 
   protected:
     PROJBasedOperation(const PROJBasedOperation &) = default;
diff --git a/include/proj/io.hpp b/include/proj/io.hpp
index be293eb9..2839896e 100644
--- a/include/proj/io.hpp
+++ b/include/proj/io.hpp
@@ -832,6 +832,7 @@ class PROJ_GCC_DLL DatabaseContext {
                                               bool &inverse) const;
 
     PROJ_DLL bool lookForGridInfo(const std::string &projFilename,
+                                  bool considerKnownGridsAsAvailable,
                                   std::string &fullFilename,
                                   std::string &packageName, std::string &url,
                                   bool &directDownload, bool &openLicense,
@@ -1050,7 +1051,8 @@ class PROJ_GCC_DLL AuthorityFactory {
         const std::string &sourceCRSAuthName, const std::string &sourceCRSCode,
         const std::string &targetCRSAuthName, const std::string &targetCRSCode,
         bool usePROJAlternativeGridNames, bool discardIfMissingGrid,
-        bool discardSuperseded, bool tryReverseOrder = false,
+        bool considerKnownGridsAsAvailable, bool discardSuperseded,
+        bool tryReverseOrder = false,
         bool reportOnlyIntersectingTransformations = false,
         const metadata::ExtentPtr &intersectingExtent1 = nullptr,
         const metadata::ExtentPtr &intersectingExtent2 = nullptr) const;
@@ -1060,7 +1062,7 @@ class PROJ_GCC_DLL AuthorityFactory {
         const std::string &sourceCRSAuthName, const std::string &sourceCRSCode,
         const std::string &targetCRSAuthName, const std::string &targetCRSCode,
         bool usePROJAlternativeGridNames, bool discardIfMissingGrid,
-        bool discardSuperseded,
+        bool considerKnownGridsAsAvailable, bool discardSuperseded,
         const std::vector<std::pair<std::string, std::string>>
             &intermediateCRSAuthCodes,
         ObjectType allowedIntermediateObjectType = ObjectType::CRS,
@@ -1126,7 +1128,7 @@ class PROJ_GCC_DLL AuthorityFactory {
         const std::string &sourceCRSCode, const crs::CRSNNPtr &targetCRS,
         const std::string &targetCRSAuthName, const std::string &targetCRSCode,
         bool usePROJAlternativeGridNames, bool discardIfMissingGrid,
-        bool discardSuperseded,
+        bool considerKnownGridsAsAvailable, bool discardSuperseded,
         const std::vector<std::string> &allowedAuthorities,
         const metadata::ExtentPtr &intersectingExtent1,
         const metadata::ExtentPtr &intersectingExtent2) const;