Extract logging logic

Previously logging logic was scattered over OS class implementations
with plenty of duplication. Major changes in this commit:

 - Extracted logging logic into a separate Logger hierarchy. It allows
   easy configuration of logging mechanism depending on compile-time or
   run-time configuration.

 - Implemented RotatedFileLogger which is usually used with StdLogger,
   providing persistency of logs. It is often important to be able to
   obtain logs of the game even in production to be able to understand
   what happened prior to some problem. On mobile there previously was
   no way to obtain the logs aside from having the device connected to
   your machine.

 - flush() is not performed in release mode for every logged line. It
   is only performed for errors.

15 files changed, 401 insertions, 0 deletions

diff --git a/core/io/file_access_buffered_fa.h b/core/io/file_access_buffered_fa.h
index 9e41834561..309fc16d09 100644
--- a/core/io/file_access_buffered_fa.h
+++ b/core/io/file_access_buffered_fa.h
@@ -76,6 +76,11 @@ protected:
 	};
 
 public:
+	void flush() {
+
+		f.flush();
+	};
+
 	void store_8(uint8_t p_dest) {
 
 		f.store_8(p_dest);
diff --git a/core/io/file_access_compressed.cpp b/core/io/file_access_compressed.cpp
index 4750945854..514e3c65f0 100644
--- a/core/io/file_access_compressed.cpp
+++ b/core/io/file_access_compressed.cpp
@@ -338,6 +338,13 @@ Error FileAccessCompressed::get_error() const {
 	return read_eof ? ERR_FILE_EOF : OK;
 }
 
+void FileAccessCompressed::flush() {
+	ERR_FAIL_COND(!f);
+	ERR_FAIL_COND(!writing);
+
+	// compressed files keep data in memory till close()
+}
+
 void FileAccessCompressed::store_8(uint8_t p_dest) {
 
 	ERR_FAIL_COND(!f);
diff --git a/core/io/file_access_compressed.h b/core/io/file_access_compressed.h
index 1a57e2d4ee..1d99e5bfd4 100644
--- a/core/io/file_access_compressed.h
+++ b/core/io/file_access_compressed.h
@@ -84,6 +84,7 @@ public:
 
 	virtual Error get_error() const; ///< get last error
 
+	virtual void flush();
 	virtual void store_8(uint8_t p_dest); ///< store a byte
 
 	virtual bool file_exists(const String &p_name); ///< return true if a file exists
diff --git a/core/io/file_access_encrypted.cpp b/core/io/file_access_encrypted.cpp
index 461c5bafe2..c93e12f7da 100644
--- a/core/io/file_access_encrypted.cpp
+++ b/core/io/file_access_encrypted.cpp
@@ -268,6 +268,12 @@ void FileAccessEncrypted::store_buffer(const uint8_t *p_src, int p_length) {
 	}
 }
 
+void FileAccessEncrypted::flush() {
+	ERR_FAIL_COND(!writing);
+
+	// encrypted files keep data in memory till close()
+}
+
 void FileAccessEncrypted::store_8(uint8_t p_dest) {
 
 	ERR_FAIL_COND(!writing);
diff --git a/core/io/file_access_encrypted.h b/core/io/file_access_encrypted.h
index 82f60ac654..d83fed3e0e 100644
--- a/core/io/file_access_encrypted.h
+++ b/core/io/file_access_encrypted.h
@@ -71,6 +71,7 @@ public:
 
 	virtual Error get_error() const; ///< get last error
 
+	virtual void flush();
 	virtual void store_8(uint8_t p_dest); ///< store a byte
 	virtual void store_buffer(const uint8_t *p_src, int p_length); ///< store an array of bytes
 
diff --git a/core/io/file_access_memory.cpp b/core/io/file_access_memory.cpp
index b948394385..0a5815fca8 100644
--- a/core/io/file_access_memory.cpp
+++ b/core/io/file_access_memory.cpp
@@ -170,6 +170,10 @@ Error FileAccessMemory::get_error() const {
 	return pos >= length ? ERR_FILE_EOF : OK;
 }
 
+void FileAccessMemory::flush() {
+	ERR_FAIL_COND(!data);
+}
+
 void FileAccessMemory::store_8(uint8_t p_byte) {
 
 	ERR_FAIL_COND(!data);
diff --git a/core/io/file_access_memory.h b/core/io/file_access_memory.h
index b7b8430089..23392719b4 100644
--- a/core/io/file_access_memory.h
+++ b/core/io/file_access_memory.h
@@ -62,6 +62,7 @@ public:
 
 	virtual Error get_error() const; ///< get last error
 
+	virtual void flush();
 	virtual void store_8(uint8_t p_byte); ///< store a byte
 	virtual void store_buffer(const uint8_t *p_src, int p_length); ///< store an array of bytes
 
diff --git a/core/io/file_access_network.cpp b/core/io/file_access_network.cpp
index 8c624226a1..a224abd9e7 100644
--- a/core/io/file_access_network.cpp
+++ b/core/io/file_access_network.cpp
@@ -456,6 +456,10 @@ Error FileAccessNetwork::get_error() const {
 	return pos == total_size ? ERR_FILE_EOF : OK;
 }
 
+void FileAccessNetwork::flush() {
+	ERR_FAIL();
+}
+
 void FileAccessNetwork::store_8(uint8_t p_dest) {
 
 	ERR_FAIL();
diff --git a/core/io/file_access_network.h b/core/io/file_access_network.h
index abbe378b60..20614476d0 100644
--- a/core/io/file_access_network.h
+++ b/core/io/file_access_network.h
@@ -155,6 +155,7 @@ public:
 
 	virtual Error get_error() const; ///< get last error
 
+	virtual void flush();
 	virtual void store_8(uint8_t p_dest); ///< store a byte
 
 	virtual bool file_exists(const String &p_path); ///< return true if a file exists
diff --git a/core/io/file_access_pack.cpp b/core/io/file_access_pack.cpp
index ff4c28ec39..a7eb8ce6a9 100644
--- a/core/io/file_access_pack.cpp
+++ b/core/io/file_access_pack.cpp
@@ -293,6 +293,11 @@ Error FileAccessPack::get_error() const {
 	return OK;
 }
 
+void FileAccessPack::flush() {
+
+	ERR_FAIL();
+}
+
 void FileAccessPack::store_8(uint8_t p_dest) {
 
 	ERR_FAIL();
diff --git a/core/io/file_access_pack.h b/core/io/file_access_pack.h
index 3deb0d2bd3..12187a353a 100644
--- a/core/io/file_access_pack.h
+++ b/core/io/file_access_pack.h
@@ -161,6 +161,7 @@ public:
 
 	virtual Error get_error() const;
 
+	virtual void flush();
 	virtual void store_8(uint8_t p_dest);
 
 	virtual void store_buffer(const uint8_t *p_src, int p_length);
diff --git a/core/io/file_access_zip.cpp b/core/io/file_access_zip.cpp
index 73b23ac702..ec809011a9 100644
--- a/core/io/file_access_zip.cpp
+++ b/core/io/file_access_zip.cpp
@@ -353,6 +353,11 @@ Error FileAccessZip::get_error() const {
 	return OK;
 };
 
+void FileAccessZip::flush() {
+
+	ERR_FAIL();
+}
+
 void FileAccessZip::store_8(uint8_t p_dest) {
 
 	ERR_FAIL();
diff --git a/core/io/file_access_zip.h b/core/io/file_access_zip.h
index a40e1a753d..0977b241ee 100644
--- a/core/io/file_access_zip.h
+++ b/core/io/file_access_zip.h
@@ -108,6 +108,7 @@ public:
 
 	virtual Error get_error() const; ///< get last error
 
+	virtual void flush();
 	virtual void store_8(uint8_t p_dest); ///< store a byte
 	virtual bool file_exists(const String &p_name); ///< return true if a file exists
 
diff --git a/core/io/logger.cpp b/core/io/logger.cpp
new file mode 100644
index 0000000000..7ea5f06d7e
--- /dev/null
+++ b/core/io/logger.cpp
@@ -0,0 +1,252 @@
+/*************************************************************************/
+/*  logger.cpp                                                           */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "logger.h"
+#include "os/dir_access.h"
+#include "os/os.h"
+#include "print_string.h"
+
+bool Logger::should_log(bool p_err) {
+	return (!p_err || _print_error_enabled) && (p_err || _print_line_enabled);
+}
+
+void Logger::log_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type) {
+	if (!should_log(true)) {
+		return;
+	}
+
+	const char *err_type = "**ERROR**";
+	switch (p_type) {
+		case ERR_ERROR: err_type = "**ERROR**"; break;
+		case ERR_WARNING: err_type = "**WARNING**"; break;
+		case ERR_SCRIPT: err_type = "**SCRIPT ERROR**"; break;
+		case ERR_SHADER: err_type = "**SHADER ERROR**"; break;
+		default: ERR_PRINT("Unknown error type"); break;
+	}
+
+	const char *err_details;
+	if (p_rationale && *p_rationale)
+		err_details = p_rationale;
+	else
+		err_details = p_code;
+
+	logf_error("%s: %s\n", err_type, err_details);
+	logf_error("   At: %s:%i:%s() - %s\n", p_file, p_line, p_function, p_code);
+}
+
+void Logger::logf(const char *p_format, ...) {
+	if (!should_log(false)) {
+		return;
+	}
+
+	va_list argp;
+	va_start(argp, p_format);
+
+	logv(p_format, argp, false);
+
+	va_end(argp);
+}
+
+void Logger::logf_error(const char *p_format, ...) {
+	if (!should_log(true)) {
+		return;
+	}
+
+	va_list argp;
+	va_start(argp, p_format);
+
+	logv(p_format, argp, true);
+
+	va_end(argp);
+}
+
+Logger::~Logger() {}
+
+void RotatedFileLogger::close_file() {
+	if (file) {
+		memdelete(file);
+		file = NULL;
+	}
+}
+
+void RotatedFileLogger::clear_old_backups() {
+	int max_backups = max_files - 1; // -1 for the current file
+
+	String basename = base_path.get_basename();
+	String extension = "." + base_path.get_extension();
+
+	DirAccess *da = DirAccess::open(base_path.get_base_dir());
+	if (!da) {
+		return;
+	}
+
+	da->list_dir_begin();
+	String f = da->get_next();
+	Set<String> backups;
+	while (f != String()) {
+		if (!da->current_is_dir() && f.begins_with(basename) && f.ends_with(extension) && f != base_path) {
+			backups.insert(f);
+		}
+		f = da->get_next();
+	}
+	da->list_dir_end();
+
+	if (backups.size() > max_backups) {
+		// since backups are appended with timestamp and Set iterates them in sorted order,
+		// first backups are the oldest
+		int to_delete = backups.size() - max_backups;
+		for (Set<String>::Element *E = backups.front(); E && to_delete > 0; E = E->next(), --to_delete) {
+			da->remove(E->get());
+		}
+	}
+
+	memdelete(da);
+}
+
+void RotatedFileLogger::rotate_file() {
+	close_file();
+
+	if (FileAccess::exists(base_path)) {
+		if (max_files > 1) {
+			char timestamp[21];
+			OS::Date date = OS::get_singleton()->get_date();
+			OS::Time time = OS::get_singleton()->get_time();
+			sprintf(timestamp, "-%04d-%02d-%02d-%02d-%02d-%02d", date.year, date.month, date.day + 1, time.hour, time.min, time.sec);
+
+			String backup_name = base_path.get_basename() + timestamp + "." + base_path.get_extension();
+
+			DirAccess *da = DirAccess::open(base_path.get_base_dir());
+			if (da) {
+				da->copy(base_path, backup_name);
+				memdelete(da);
+			}
+			clear_old_backups();
+		}
+	} else {
+		DirAccess *da = DirAccess::create(DirAccess::ACCESS_USERDATA);
+		if (da) {
+			da->make_dir_recursive(base_path.get_base_dir());
+			memdelete(da);
+		}
+	}
+
+	file = FileAccess::open(base_path, FileAccess::WRITE);
+}
+
+RotatedFileLogger::RotatedFileLogger(const String &p_base_path, int p_max_files) {
+	file = NULL;
+	base_path = p_base_path.simplify_path();
+	max_files = p_max_files > 0 ? p_max_files : 1;
+
+	rotate_file();
+}
+
+void RotatedFileLogger::logv(const char *p_format, va_list p_list, bool p_err) {
+	if (!should_log(p_err)) {
+		return;
+	}
+
+	if (file) {
+		const int static_buf_size = 512;
+		char static_buf[static_buf_size];
+		char *buf = static_buf;
+		int len = vsnprintf(buf, static_buf_size, p_format, p_list);
+		if (len >= static_buf_size) {
+			buf = (char *)Memory::alloc_static(len + 1);
+			vsnprintf(buf, len + 1, p_format, p_list);
+		}
+		file->store_buffer((uint8_t *)buf, len);
+		if (len >= static_buf_size) {
+			Memory::free_static(buf);
+		}
+#ifdef DEBUG_ENABLED
+		const bool need_flush = true;
+#else
+		bool need_flush = p_err;
+#endif
+		if (need_flush) {
+			file->flush();
+		}
+	}
+}
+
+RotatedFileLogger::~RotatedFileLogger() {
+	close_file();
+}
+
+void StdLogger::logv(const char *p_format, va_list p_list, bool p_err) {
+	if (!should_log(p_err)) {
+		return;
+	}
+
+	if (p_err) {
+		vfprintf(stderr, p_format, p_list);
+	} else {
+		vprintf(p_format, p_list);
+#ifdef DEBUG_ENABLED
+		fflush(stdout);
+#endif
+	}
+}
+
+StdLogger::~StdLogger() {}
+
+CompositeLogger::CompositeLogger(Vector<Logger *> p_loggers) {
+	loggers = p_loggers;
+}
+
+void CompositeLogger::logv(const char *p_format, va_list p_list, bool p_err) {
+	if (!should_log(p_err)) {
+		return;
+	}
+
+	for (int i = 0; i < loggers.size(); ++i) {
+		va_list list_copy;
+		va_copy(list_copy, p_list);
+		loggers[i]->logv(p_format, list_copy, p_err);
+		va_end(list_copy);
+	}
+}
+
+void CompositeLogger::log_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type) {
+	if (!should_log(true)) {
+		return;
+	}
+
+	for (int i = 0; i < loggers.size(); ++i) {
+		loggers[i]->log_error(p_function, p_file, p_line, p_code, p_rationale, p_type);
+	}
+}
+
+CompositeLogger::~CompositeLogger() {
+	for (int i = 0; i < loggers.size(); ++i) {
+		memdelete(loggers[i]);
+	}
+}
diff --git a/core/io/logger.h b/core/io/logger.h
new file mode 100644
index 0000000000..cf0cc7699f
--- /dev/null
+++ b/core/io/logger.h
@@ -0,0 +1,107 @@
+/*************************************************************************/
+/*  logger.h                                                             */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef LOGGER_H
+#define LOGGER_H
+
+#include "os/file_access.h"
+#include "ustring.h"
+#include "vector.h"
+#include <stdarg.h>
+
+class Logger {
+protected:
+	bool should_log(bool p_err);
+
+public:
+	enum ErrorType {
+		ERR_ERROR,
+		ERR_WARNING,
+		ERR_SCRIPT,
+		ERR_SHADER
+	};
+
+	virtual void logv(const char *p_format, va_list p_list, bool p_err) = 0;
+	virtual void log_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type = ERR_ERROR);
+
+	void logf(const char *p_format, ...);
+	void logf_error(const char *p_format, ...);
+
+	virtual ~Logger();
+};
+
+/**
+ * Writes messages to stdout/stderr.
+ */
+class StdLogger : public Logger {
+
+public:
+	virtual void logv(const char *p_format, va_list p_list, bool p_err);
+	virtual ~StdLogger();
+};
+
+/**
+ * Writes messages to the specified file. If the file already exists, creates a copy (backup)
+ * of it with timestamp appended to the file name. Maximum number of backups is configurable.
+ * When maximum is reached, the oldest backups are erased. With the maximum being equal to 1,
+ * it acts as a simple file logger.
+ */
+class RotatedFileLogger : public Logger {
+	String base_path;
+	int max_files;
+
+	FileAccess *file;
+
+	void rotate_file_without_closing();
+	void close_file();
+	void clear_old_backups();
+	void rotate_file();
+
+public:
+	RotatedFileLogger(const String &p_base_path, int p_max_files = 10);
+
+	virtual void logv(const char *p_format, va_list p_list, bool p_err);
+
+	virtual ~RotatedFileLogger();
+};
+
+class CompositeLogger : public Logger {
+	Vector<Logger *> loggers;
+
+public:
+	CompositeLogger(Vector<Logger *> p_loggers);
+
+	virtual void logv(const char *p_format, va_list p_list, bool p_err);
+	virtual void log_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type = ERR_ERROR);
+
+	virtual ~CompositeLogger();
+};
+
+#endif
\ No newline at end of file