Add C API to QPDFLogger

2 files changed, 102 insertions, 2 deletions

diff --git a/include/qpdf/QPDFLogger.hh b/include/qpdf/QPDFLogger.hh
index cd439caa..54ab7efe 100644
--- a/include/qpdf/QPDFLogger.hh
+++ b/include/qpdf/QPDFLogger.hh
@@ -130,9 +130,9 @@ class QPDFLogger
     void setError(std::shared_ptr<Pipeline>);
     // See notes above about the save pipeline
     QPDF_DLL
-    void setSave(std::shared_ptr<Pipeline>);
+    void setSave(std::shared_ptr<Pipeline>, bool only_if_not_set);
     QPDF_DLL
-    void saveToStandardOutput();
+    void saveToStandardOutput(bool only_if_not_set);
 
     // Shortcut for logic to reset output to new output/error streams.
     // out_stream is used for info, err_stream is used for error, and
diff --git a/include/qpdf/qpdflogger-c.h b/include/qpdf/qpdflogger-c.h
new file mode 100644
index 00000000..9d31f79c
--- /dev/null
+++ b/include/qpdf/qpdflogger-c.h
@@ -0,0 +1,100 @@
+/* Copyright (c) 2005-2022 Jay Berkenbilt
+ *
+ * This file is part of qpdf.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Versions of qpdf prior to version 7 were released under the terms
+ * of version 2.0 of the Artistic License. At your option, you may
+ * continue to consider qpdf to be licensed under those terms. Please
+ * see the manual for additional information.
+ */
+
+#ifndef QPDFLOGGER_H
+#define QPDFLOGGER_H
+
+/*
+ * This file provides a C API for QPDFLogger. See QPDFLogger.hh for
+ * information about the logger.
+ */
+
+#include <qpdf/DLL.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    /* To operate on a logger, you need a handle to it. call
+     * qpdflogger_default_logger to get a handle for the default
+     * logger. The qpdf and qpdfjob functions may offer ways to get
+     * other logger handles. When you're done with the logger handler,
+     * call qpdflogger_cleanup. This does not destroy the underlying
+     * log object. It just cleans up the handle to it.
+     */
+
+    typedef struct _qpdflogger_handle* qpdflogger_handle;
+    QPDF_DLL
+    qpdflogger_handle qpdflogger_default_logger();
+
+    QPDF_DLL
+    void qpdflogger_cleanup(qpdflogger_handle* l);
+
+    enum qpdf_log_dest_e {
+        qpdf_log_dest_default = 0,
+        qpdf_log_dest_stdout = 1,
+        qpdf_log_dest_stderr = 2,
+        qpdf_log_dest_discard = 3,
+        qpdf_log_dest_custom = 4,
+    };
+
+    typedef void (*qpdf_log_fn_t)(char const* data, size_t len, void* udata);
+
+    QPDF_DLL
+    void qpdflogger_set_info(
+        qpdflogger_handle l,
+        enum qpdf_log_dest_e dest,
+        qpdf_log_fn_t fn,
+        void* udata);
+    QPDF_DLL
+    void qpdflogger_set_warn(
+        qpdflogger_handle l,
+        enum qpdf_log_dest_e dest,
+        qpdf_log_fn_t fn,
+        void* udata);
+    QPDF_DLL
+    void qpdflogger_set_error(
+        qpdflogger_handle l,
+        enum qpdf_log_dest_e dest,
+        qpdf_log_fn_t fn,
+        void* udata);
+
+    /* A non-zero value for only_if_not_set means that the save
+     * pipeline will only be changed if it is not already set.
+     */
+    QPDF_DLL
+    void qpdflogger_set_save(
+        qpdflogger_handle l,
+        enum qpdf_log_dest_e dest,
+        qpdf_log_fn_t fn,
+        void* udata,
+        int only_if_not_set);
+    QPDF_DLL
+    void qpdflogger_save_to_standard_output(
+        qpdflogger_handle l, int only_if_not_set);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // QPDFLOGGER_H