diagnostics: add diagnostic_output_format class

diagnostics: add diagnostic_output_format class

Eliminate various global variables in the json/sarif output code by
bundling together callbacks and state into a new diagnostic_output_format
class, with per-output-format subclasses.

No functional change intended.

gcc/ChangeLog:
	* diagnostic-format-json.cc (toplevel_array): Remove global in
	favor of json_output_format::m_top_level_array.
	(cur_group): Likewise, for json_output_format::m_cur_group.
	(cur_children_array): Likewise, for
	json_output_format::m_cur_children_array.
	(class json_output_format): New.
	(json_begin_diagnostic): Remove, in favor of
	json_output_format::on_begin_diagnostic.
	(json_end_diagnostic): Convert to...
	(json_output_format::on_end_diagnostic): ...this.
	(json_begin_group): Remove, in favor of
	json_output_format::on_begin_group.
	(json_end_group): Remove, in favor of
	json_output_format::on_end_group.
	(json_flush_to_file): Remove, in favor of
	json_output_format::flush_to_file.
	(json_stderr_final_cb): Remove, in favor of json_output_format
	dtor.
	(json_output_base_file_name): Remove global.
	(class json_stderr_output_format): New.
	(json_file_final_cb): Remove.
	(class json_file_output_format): New.
	(json_emit_diagram): Remove.
	(diagnostic_output_format_init_json): Update.
	(diagnostic_output_format_init_json_file): Update.
	* diagnostic-format-sarif.cc (the_builder): Remove this global,
	moving to a field of the sarif_output_format.
	(sarif_builder::maybe_make_artifact_content_object): Use the
	context's m_file_cache.
	(get_source_lines): Convert to...
	(sarif_builder::get_source_lines): ...this, using context's
	m_file_cache.
	(sarif_begin_diagnostic): Remove, in favor of
	sarif_output_format::on_begin_diagnostic.
	(sarif_end_diagnostic): Remove, in favor of
	sarif_output_format::on_end_diagnostic.
	(sarif_begin_group): Remove, in favor of
	sarif_output_format::on_begin_group.
	(sarif_end_group): Remove, in favor of
	sarif_output_format::on_end_group.
	(sarif_flush_to_file): Delete.
	(sarif_stderr_final_cb): Delete.
	(sarif_output_base_file_name): Delete.
	(sarif_file_final_cb): Delete.
	(class sarif_output_format): New.
	(sarif_emit_diagram): Delete.
	(class sarif_stream_output_format): New.
	(class sarif_file_output_format): New.
	(diagnostic_output_format_init_sarif): Update.
	(diagnostic_output_format_init_sarif_stderr): Update.
	(diagnostic_output_format_init_sarif_file): Update.
	(diagnostic_output_format_init_sarif_stream): Update.
	* diagnostic-show-locus.cc (diagnostic_show_locus): Update.
	* diagnostic.cc (default_diagnostic_final_cb): Delete, moving to
	diagnostic_text_output_format's dtor.
	(diagnostic_initialize): Update, making a new instance of
	diagnostic_text_output_format.
	(diagnostic_finish): Delete m_output_format, rather than calling
	final_cb.
	(diagnostic_report_diagnostic): Assert that m_output_format is
	non-NULL.  Replace call to begin_group_cb with call to
	m_output_format->on_begin_group.  Replace call to
	diagnostic_starter with call to
	m_output_format->on_begin_diagnostic.  Replace call to
	diagnostic_finalizer with call to
	m_output_format->on_end_diagnostic.
	(diagnostic_emit_diagram): Replace both optional call to
	m_diagrams.m_emission_cb and default implementation with call to
	m_output_format->on_diagram.  Move default implementation to
	diagnostic_text_output_format::on_diagram.
	(auto_diagnostic_group::~auto_diagnostic_group): Replace call to
	end_group_cb with call to m_output_format->on_end_group.
	(diagnostic_text_output_format::~diagnostic_text_output_format):
	New, based on default_diagnostic_final_cb.
	(diagnostic_text_output_format::on_begin_diagnostic): New, based
	on code from diagnostic_report_diagnostic.
	(diagnostic_text_output_format::on_end_diagnostic): Likewise.
	(diagnostic_text_output_format::on_diagram): New, based on code
	from diagnostic_emit_diagram.
	* diagnostic.h (class diagnostic_output_format): New.
	(class diagnostic_text_output_format): New.
	(diagnostic_context::begin_diagnostic): Move to...
	(diagnostic_context::m_text_callbacks::begin_diagnostic): ...here.
	(diagnostic_context::start_span): Move to...
	(diagnostic_context::m_text_callbacks::start_span): ...here.
	(diagnostic_context::end_diagnostic): Move to...
	(diagnostic_context::m_text_callbacks::end_diagnostic): ...here.
	(diagnostic_context::begin_group_cb): Remove, in favor of
	m_output_format->on_begin_group.
	(diagnostic_context::end_group_cb): Remove, in favor of
	m_output_format->on_end_group.
	(diagnostic_context::final_cb): Remove, in favor of
	m_output_format's dtor.
	(diagnostic_context::m_output_format): New field.
	(diagnostic_context::m_diagrams.m_emission_cb): Remove, in favor
	of m_output_format->on_diagram.
	(diagnostic_starter): Update.
	(diagnostic_finalizer): Update.
	(diagnostic_output_format_init_sarif_stream): New.
	* input.cc (location_get_source_line): Move implementation apart from
	call to diagnostic_file_cache_init to...
	(file_cache::get_source_line): ...this new function...
	(location_get_source_line): ...and reintroduce, rewritten in terms of
	file_cache::get_source_line.
	(get_source_file_content): Likewise, refactor into...
	(file_cache::get_source_file_content): ...this new function.
	* input.h (file_cache::get_source_line): New decl.
	(file_cache::get_source_file_content): New decl.
	* selftest-diagnostic.cc
	(test_diagnostic_context::test_diagnostic_context): Update.
	* tree-diagnostic-path.cc (event_range::print): Update for
	change to diagnostic_context's start_span callback.

gcc/fortran/ChangeLog:
	* error.cc (gfc_diagnostics_init): Update for change to start_span.

gcc/jit/ChangeLog:
	* dummy-frontend.cc (jit_langhook_init): Update for change to
	diagnostic_context callbacks.

gcc/testsuite/ChangeLog:
	* gcc.dg/plugin/diagnostic_group_plugin.c
	(test_begin_group_cb, test_end_group_cb): Replace with...
	(class test_output_format): ...this new subclass.
	(plugin_init): Update.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>