File-based iteration encoding: Re-parse padding when necessary

include/openPMD/Error.hpp

@@ -50,5 +50,17 @@ namespace error
         OperationUnsupportedInBackend(
             std::string backend_in, std::string what );
     };
+
+    /**
+     * @brief The API was used in an illegal way.
+     *
+     * Example: File-based iteration encoding is selected without specifying an
+     *     expansion pattern.
+     */
+    class WrongAPIUsage : public Error
+    {
+    public:
+        WrongAPIUsage( std::string what );
+    };
 }
 }

include/openPMD/Series.hpp

@@ -84,7 +84,7 @@ class SeriesData : public AttributableData
     std::string m_name;
     std::string m_filenamePrefix;
     std::string m_filenamePostfix;
-    int m_filenamePadding;
+    int m_filenamePadding = -1;
     IterationEncoding m_iterationEncoding{};
     Format m_format;
     /**
@@ -346,6 +346,8 @@ class SeriesInterface : public AttributableInterface
         }    }
 
     std::unique_ptr< ParsedInput > parseInput(std::string);
+    bool hasExpansionPattern( std::string filenameWithExtension );
+    bool reparseExpansionPattern( std::string filenameWithExtension );
     void init(std::shared_ptr< AbstractIOHandler >, std::unique_ptr< ParsedInput >);
     void initDefaults( IterationEncoding );
     /**

src/Error.cpp

@@ -15,5 +15,10 @@ namespace error
         , backend{ std::move( backend_in ) }
     {
     }
+
+    WrongAPIUsage::WrongAPIUsage( std::string what )
+        : Error( "Wrong API usage: " + what )
+    {
+    }
 }
 }

src/Series.cpp

@@ -25,6 +25,7 @@
 #include "openPMD/IO/AbstractIOHandler.hpp"
 #include "openPMD/IO/AbstractIOHandlerHelper.hpp"
 #include "openPMD/IO/Format.hpp"
+#include "openPMD/Error.hpp"
 #include "openPMD/ReadIterations.hpp"
 #include "openPMD/Series.hpp"
 #include "openPMD/version.hpp"
@@ -87,7 +88,7 @@ struct SeriesInterface::ParsedInput
     IterationEncoding iterationEncoding;
     std::string filenamePrefix;
     std::string filenamePostfix;
-    int filenamePadding;
+    int filenamePadding = -1;
 };  //ParsedInput
 
 SeriesInterface::SeriesInterface(
@@ -280,8 +281,20 @@ SeriesInterface::setIterationEncoding(IterationEncoding ie)
     switch( ie )
     {
         case IterationEncoding::fileBased:
-            setIterationFormat(series.m_name);
-            setAttribute("iterationEncoding", std::string("fileBased"));
+            setIterationFormat( series.m_name );
+            setAttribute( "iterationEncoding", std::string( "fileBased" ) );
+            // This checks that the name contains the expansion pattern
+            // (e.g. %T) and parses it
+            if( series.m_filenamePadding < 0 )
+            {
+                if( !reparseExpansionPattern( series.m_name ) )
+                {
+                    throw error::WrongAPIUsage(
+                        "For fileBased formats the iteration expansion pattern "
+                        "%T must "
+                        "be included in the file name" );
+                }
+            }
             break;
         case IterationEncoding::groupBased:
             setIterationFormat(BASEPATH);
@@ -330,8 +343,27 @@ SeriesInterface::setName(std::string const& n)
     if( written() )
         throw std::runtime_error("A files name can not (yet) be changed after it has been written.");
 
-    if( series.m_iterationEncoding == IterationEncoding::fileBased && !auxiliary::contains(series.m_name, "%T") )
-            throw std::runtime_error("For fileBased formats the iteration regex %T must be included in the file name");
+    if( series.m_iterationEncoding == IterationEncoding::fileBased )
+    {
+        // If the filename specifies an expansion pattern, set it.
+        // If not, check if one is already active.
+        // Our filename parser expects an extension, so just add any and ignore
+        // the result for that
+        if( hasExpansionPattern( n + ".json" ) )
+        {
+            reparseExpansionPattern( n + ".json" );
+        }
+        else if( series.m_filenamePadding < 0 )
+        {
+            throw error::WrongAPIUsage(
+                "For fileBased formats the iteration expansion pattern %T must "
+                "be included in the file name" );
+        }
+        else
+        {
+            // no-op, keep the old pattern and set the new name
+        }
+    }
 
     series.m_name = n;
     dirty() = true;
@@ -418,6 +450,27 @@ SeriesInterface::parseInput(std::string filepath)
     return input;
 }
 
+bool SeriesInterface::hasExpansionPattern( std::string filenameWithExtension )
+{
+    auto input = parseInput( std::move( filenameWithExtension ) );
+    return input->iterationEncoding == IterationEncoding::fileBased;
+}
+
+bool SeriesInterface::reparseExpansionPattern(
+    std::string filenameWithExtension )
+{
+    auto input = parseInput( std::move( filenameWithExtension ) );
+    if( input->iterationEncoding != IterationEncoding::fileBased )
+    {
+        return false;
+    }
+    auto & series = get();
+    series.m_filenamePrefix = input->filenamePrefix;
+    series.m_filenamePostfix = input->filenamePostfix;
+    series.m_filenamePadding = input->filenamePadding;
+    return true;
+}
+
 void SeriesInterface::init(
     std::shared_ptr< AbstractIOHandler > ioHandler,
     std::unique_ptr< SeriesInterface::ParsedInput > input )

src/binding/python/Error.cpp

@@ -10,6 +10,8 @@ void init_Error( py::module & m )
     auto & baseError = py::register_exception< Error >( m, "Error" );
     py::register_exception< error::OperationUnsupportedInBackend >(
         m, "ErrorOperationUnsupportedInBackend", baseError );
+    py::register_exception< error::WrongAPIUsage >(
+        m, "ErrorWrongAPIUsage", baseError );
 
 #ifndef NDEBUG
     m.def( "test_throw", []( std::string description ) {

test/CoreTest.cpp

@@ -688,14 +688,14 @@ TEST_CASE( "structure_test", "[core]" )
 
 TEST_CASE( "wrapper_test", "[core]" )
 {
-    Series o = Series("./new_openpmd_output.json", Access::CREATE);
+    Series o = Series("./new_openpmd_output_%T.json", Access::CREATE);
 
     o.setOpenPMDextension(42);
     o.setIterationEncoding(IterationEncoding::fileBased);
     Series copy = o;
     REQUIRE(copy.openPMDextension() == 42);
     REQUIRE(copy.iterationEncoding() == IterationEncoding::fileBased);
-    REQUIRE(copy.name() == "new_openpmd_output");
+    REQUIRE(copy.name() == "new_openpmd_output_%T");
     copy.setOpenPMD("1.2.0");
     copy.setIterationEncoding(IterationEncoding::groupBased);
     copy.setName("other_name");

test/SerialIOTest.cpp

@@ -4566,3 +4566,52 @@ TEST_CASE( "no_explicit_flush", "[serial]" )
         no_explicit_flush( "../samples/no_explicit_flush." + t );
     }
 }
+
+TEST_CASE( "late_setting_of_iterationencoding", "[serial]" )
+{
+    {
+        ::openPMD::Series series = ::openPMD::Series(
+            "../samples/error.json", ::openPMD::Access::CREATE );
+        series.iterations[ 10 ];
+        REQUIRE_THROWS_WITH(
+            series.setIterationEncoding(
+                ::openPMD::IterationEncoding::fileBased ),
+            Catch::Equals( "Wrong API usage: For fileBased formats the "
+                           "iteration expansion pattern %T must "
+                           "be included in the file name" ) );
+        series.flush();
+    }
+    {
+        ::openPMD::Series series = ::openPMD::Series(
+            "../samples/asdf_%T.json",
+            ::openPMD::Access::CREATE );
+        series.iterations[ 10 ];
+        series.setName(
+            "change_name_%T" );
+        series.flush();
+    }
+    {
+        ::openPMD::Series series = ::openPMD::Series(
+            "../samples/change_name_keep_filename_%T.json",
+            ::openPMD::Access::CREATE );
+        series.iterations[ 10 ];
+        series.setName(
+            "expansion_pattern_was_specified_previously_filename_will_stay" );
+        series.flush();
+    }
+    {
+        ::openPMD::Series series = ::openPMD::Series(
+            "../samples/asdf.json", ::openPMD::Access::CREATE );
+        series.iterations[ 10 ];
+        series.setName( "change_name_and_encoding_%T" );
+        series.setIterationEncoding( IterationEncoding::fileBased );
+        series.flush();
+    }
+
+    REQUIRE( auxiliary::file_exists(
+        "../samples/change_name_10.json" ) );
+    REQUIRE( auxiliary::file_exists(
+        "../samples/change_name_keep_filename_10.json" ) );
+    REQUIRE( auxiliary::file_exists(
+        "../samples/change_name_and_encoding_10.json" ) );
+}