Open writer in getid command earlier

This way we'll get an error message earlier if there is a problem.

Author: joto

src/command_getid.cpp

@@ -42,6 +42,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <cstddef>
 #include <fstream>
 #include <iostream>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -245,6 +246,7 @@ bool CommandGetId::find_relations_in_relations() {
     osmium::index::RelationsMapStash stash;
 
     osmium::io::Reader reader{m_input_file, osmium::osm_entity_bits::relation, osmium::io::read_meta::no};
+    open_writer(reader);
     while (osmium::memory::Buffer buffer = reader.read()) {
         for (const auto& relation : buffer.select<osmium::Relation>()) {
             for (const auto& member : relation.members()) {
@@ -278,6 +280,7 @@ void CommandGetId::find_nodes_and_ways_in_relations() {
     m_vout << "  Reading input file to find nodes/ways in relations...\n";
 
     osmium::io::Reader reader{m_input_file, osmium::osm_entity_bits::relation, osmium::io::read_meta::no};
+    open_writer(reader);
     while (osmium::memory::Buffer buffer = reader.read()) {
         for (const auto& relation : buffer.select<osmium::Relation>()) {
             if (m_ids(osmium::item_type::relation).get(relation.positive_id())) {
@@ -298,6 +301,7 @@ void CommandGetId::find_nodes_in_ways() {
     m_vout << "  Reading input file to find nodes in ways...\n";
 
     osmium::io::Reader reader{m_input_file, osmium::osm_entity_bits::way, osmium::io::read_meta::no};
+    open_writer(reader);
     while (osmium::memory::Buffer buffer = reader.read()) {
         for (const auto& way : buffer.select<osmium::Way>()) {
             if (m_ids(osmium::item_type::way).get(way.positive_id())) {
@@ -332,19 +336,25 @@ void CommandGetId::find_referenced_objects() {
     m_vout << "Done following references.\n";
 }
 
+void CommandGetId::open_writer(osmium::io::Reader& reader) {
+    if (m_writer) {
+        return;
+    }
+
+    m_vout << "Opening output file...\n";
+    osmium::io::Header header{reader.header()};
+    setup_header(header);
+    m_writer = std::make_unique<osmium::io::Writer>(m_output_file, header, m_output_overwrite, m_fsync);
+}
+
 bool CommandGetId::run() {
     if (m_add_referenced_objects) {
         find_referenced_objects();
     }
 
     m_vout << "Opening input file...\n";
     osmium::io::Reader reader{m_input_file, get_needed_types()};
-
-    m_vout << "Opening output file...\n";
-    osmium::io::Header header{reader.header()};
-    setup_header(header);
-
-    osmium::io::Writer writer{m_output_file, header, m_output_overwrite, m_fsync};
+    open_writer(reader);
 
     m_vout << "Copying matching objects to output file...\n";
     osmium::ProgressBar progress_bar{reader.file_size(), display_progress()};
@@ -355,22 +365,22 @@ bool CommandGetId::run() {
                 if (!m_work_with_history) {
                     m_ids(object.type()).unset(object.positive_id());
                 }
-                writer(object);
+                writer()(object);
             } else if (m_ids(object.type()).get(object.positive_id())) {
                 if (!m_work_with_history) {
                     m_ids(object.type()).unset(object.positive_id());
                 }
                 if (m_remove_tags) {
                     object.remove_tags();
                 }
-                writer(object);
+                writer()(object);
             }
         }
     }
     progress_bar.done();
 
     m_vout << "Closing output file...\n";
-    writer.close();
+    writer().close();
 
     m_vout << "Closing input file...\n";
     reader.close();

src/command_getid.hpp

@@ -29,17 +29,22 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <osmium/index/id_set.hpp>
 #include <osmium/index/nwr_array.hpp>
 #include <osmium/index/relations_map.hpp>
+#include <osmium/io/reader.hpp>
+#include <osmium/io/writer.hpp>
 #include <osmium/osm/entity_bits.hpp>
 #include <osmium/osm/item_type.hpp>
 #include <osmium/osm/types.hpp>
 
 #include <cstddef>
 #include <iosfwd>
+#include <memory>
 #include <string>
 #include <vector>
 
 class CommandGetId : public CommandWithSingleOSMInput, public with_osm_output {
 
+    std::unique_ptr<osmium::io::Writer> m_writer;
+
     osmium::nwr_array<osmium::index::IdSetDense<osmium::unsigned_object_id_type>> m_matching_ids;
     osmium::nwr_array<osmium::index::IdSetDense<osmium::unsigned_object_id_type>> m_ids;
 
@@ -53,6 +58,12 @@ class CommandGetId : public CommandWithSingleOSMInput, public with_osm_output {
     osmium::osm_entity_bits::type get_needed_types() const;
     std::size_t count_ids() const noexcept;
 
+    void open_writer(osmium::io::Reader& reader);
+
+    osmium::io::Writer& writer() {
+        return *m_writer;
+    }
+
     void find_referenced_objects();
 
     void mark_rel_ids(const osmium::index::RelationsMapIndex& rel_in_rel, osmium::unsigned_object_id_type parent_id);