Clean-up: modernize pretty_xml.cpp

Since pretty_xml was converted to C++, clang-tidy had a number of grievances such as the use of NULL (instead of nullptr). Since the file is very small, it is modernized to address those issues: - Wrap libxml2 resources in RAII wrappers - Use C++ IO APIs in lieu of fprintf Signed-off-by: Jérémie Galarneau <[email protected]> Change-Id: Ie90e3e05130f7916f411e0de36e8aac72a0f790c
lttng · May 1, 2024 · f59edc7 · f59edc7
1 parent 0e9cf25
commit f59edc7
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Showing 3 changed files with 48 additions and 23 deletions.
diff --git a/tests/utils/xml-utils/common.hpp b/tests/utils/xml-utils/common.hpp
@@ -13,8 +13,37 @@
 #include <libxml/parser.h>
 #include <memory>
 
-using xml_parser_ctx_uptr = std::unique_ptr<
+namespace lttng {
+namespace libxml {
+
+using parser_ctx_uptr = std::unique_ptr<
  xmlParserCtxt,
  lttng::memory::create_deleter_class<xmlParserCtxt, xmlFreeParserCtxt>::deleter>;
+using doc_uptr =
+ std::unique_ptr<xmlDoc, lttng::memory::create_deleter_class<xmlDoc, xmlFreeDoc>::deleter>;
+
+/*
+ * Manage the global parser context of libxml2.
+ * There should only be one instance of this class per process.
+ */
+class global_parser_context {
+public:
+ global_parser_context()
+ {
+ xmlInitParser();
+ }
+
+ ~global_parser_context()
+ {
+ xmlCleanupParser();
+ }
 
+ /* Deactivate copy and assignment. */
+ global_parser_context(const global_parser_context&) = delete;
+ global_parser_context(global_parser_context&&) = delete;
+ global_parser_context& operator=(const global_parser_context&) = delete;
+ global_parser_context& operator=(global_parser_context&&) = delete;
+};
+} /* namespace libxml */
+} /* namespace lttng */
 #endif /* TESTS_UTILS_XML_UTILS_COMMON_HPP */
diff --git a/tests/utils/xml-utils/extract_xml.cpp b/tests/utils/xml-utils/extract_xml.cpp
@@ -38,6 +38,8 @@
 #include <string.h>
 #include <unistd.h>
 
+namespace ll = lttng::libxml;
+
 #if defined(LIBXML_XPATH_ENABLED)
 
 static int opt_verbose;
@@ -178,7 +180,7 @@ static int extract_xpath(const char *xml_path, const xmlChar *xpath)
  LTTNG_ASSERT(xml_path);
  LTTNG_ASSERT(xpath);
 
- xml_parser_ctx_uptr parserCtx{ xmlNewParserCtxt() };
+ ll::parser_ctx_uptr parserCtx{ xmlNewParserCtxt() };
 
  if (!parserCtx) {
  fprintf(stderr, "ERR: could not allocate an XML parser context\n");

diff --git a/tests/utils/xml-utils/pretty_xml.cpp b/tests/utils/xml-utils/pretty_xml.cpp
@@ -12,34 +12,28 @@
 
 #include "common.hpp"
 
+#include <common/scope-exit.hpp>
+
+#include <iostream>
 #include <libxml/parser.h>
 #include <unistd.h>
 
+namespace ll = lttng::libxml;
+
 int main()
 {
- xmlDocPtr doc = NULL;
-
- /* Init libxml. */
- xmlInitParser();
-
- {
- xml_parser_ctx_uptr parserCtx{ xmlNewParserCtxt() };
-
- /* Parse the XML document from stdin. */
- doc = xmlCtxtReadFd(
- parserCtx.get(), STDIN_FILENO, nullptr, nullptr, XML_PARSE_NOBLANKS);
- if (!doc) {
- fprintf(stderr, "ERR parsing: xml input invalid");
- return -1;
- }
-
- xmlDocFormatDump(stdout, doc, 1);
-
- xmlFreeDoc(doc);
+ const ll::global_parser_context global_parser_context;
+ const ll::parser_ctx_uptr parserCtx{ xmlNewParserCtxt() };
+
+ /* Parse the XML document from stdin. */
+ const ll::doc_uptr doc{ xmlCtxtReadFd(
+ parserCtx.get(), STDIN_FILENO, nullptr, nullptr, XML_PARSE_NOBLANKS) };
+ if (!doc) {
+ std::cerr << "Error: invalid XML input on stdin\n";
+ return -1;
  }
 
- /* Shutdown libxml. */
- xmlCleanupParser();
+ xmlDocFormatDump(stdout, doc.get(), 1);
 
  return 0;
 }