Курнат Андрей
99 lines
3.9 KiB
Go
99 lines
3.9 KiB
Go
package vips
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// #include <glib.h>
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import "C"
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import (
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"log"
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)
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// LogLevel is the enum controlling logging message verbosity.
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type LogLevel int
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// The logging verbosity levels classify and filter logging messages.
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// From most to least verbose, they are debug, info, message, warning, critical and error.
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const (
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LogLevelError LogLevel = C.G_LOG_LEVEL_ERROR
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LogLevelCritical LogLevel = C.G_LOG_LEVEL_CRITICAL
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LogLevelWarning LogLevel = C.G_LOG_LEVEL_WARNING
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LogLevelMessage LogLevel = C.G_LOG_LEVEL_MESSAGE
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LogLevelInfo LogLevel = C.G_LOG_LEVEL_INFO
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LogLevelDebug LogLevel = C.G_LOG_LEVEL_DEBUG
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)
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// Three global variables which keep state of the current logging handler
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// function, desired verbosity for logging and whether defaults have been
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// overridden. Set by LoggingSettings()
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var (
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currentLoggingHandlerFunction LoggingHandlerFunction
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currentLoggingVerbosity LogLevel
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currentLoggingOverridden bool
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)
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// govipsLoggingHandler is the private bridge function exported to the C library
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// and called by glib and libvips for each logging message. It will call govipsLog
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// which in turn will filter based on verbosity and direct the messages to the
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// currently chosen LoggingHandlerFunction.
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//
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//export govipsLoggingHandler
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func govipsLoggingHandler(messageDomain *C.char, messageLevel C.int, message *C.char) {
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govipsLog(C.GoString(messageDomain), LogLevel(messageLevel), C.GoString(message))
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}
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// LoggingHandlerFunction is a function which will be called for each log message.
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// By default, govips sends logging messages to os.Stderr. If you want to log elsewhere
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// such as to a file or to a state variable which you inspect yourself, define a new
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// logging handler function and set it via LoggingSettings().
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type LoggingHandlerFunction func(messageDomain string, messageLevel LogLevel, message string)
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// LoggingSettings sets the logging handler and logging verbosity for govips.
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// The handler function is the function which will be called for each log message.
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// You can define one yourself to log somewhere else besides the default (stderr).
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// Use nil as handler to use standard logging handler.
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// Verbosity is the minimum logLevel you want to log. Default is logLevelInfo
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// due to backwards compatibility but it's quite verbose for a library.
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// Suggest setting it to at least logLevelWarning. Use logLevelDebug for debugging.
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func LoggingSettings(handler LoggingHandlerFunction, verbosity LogLevel) {
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currentLoggingOverridden = true
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govipsLoggingSettings(handler, verbosity)
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}
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func govipsLoggingSettings(handler LoggingHandlerFunction, verbosity LogLevel) {
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if handler == nil {
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currentLoggingHandlerFunction = defaultLoggingHandlerFunction
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} else {
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currentLoggingHandlerFunction = handler
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}
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currentLoggingVerbosity = verbosity
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// TODO turn on debugging in libvips and redirect to handler when setting verbosity to debug
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// This way debugging information would go to the same channel as all other logging
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}
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func defaultLoggingHandlerFunction(messageDomain string, messageLevel LogLevel, message string) {
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var messageLevelDescription string
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switch messageLevel {
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case LogLevelError:
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messageLevelDescription = "error"
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case LogLevelCritical:
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messageLevelDescription = "critical"
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case LogLevelWarning:
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messageLevelDescription = "warning"
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case LogLevelMessage:
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messageLevelDescription = "message"
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case LogLevelInfo:
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messageLevelDescription = "info"
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case LogLevelDebug:
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messageLevelDescription = "debug"
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}
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log.Printf("[%v.%v] %v", messageDomain, messageLevelDescription, message)
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}
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// govipsLog is the default function used to log debug or error messages internally in govips.
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// It's used by all govips functionality directly, as well as by glib and libvips via the C bridge.
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func govipsLog(messageDomain string, messageLevel LogLevel, message string) {
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if messageLevel <= currentLoggingVerbosity {
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currentLoggingHandlerFunction(messageDomain, messageLevel, message)
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}
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}
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