gioui.org@v0.6.1-0.20240506124620-7a9ce51988ce/app/log_ios.go (about)

     1  // SPDX-License-Identifier: Unlicense OR MIT
     2  
     3  //go:build darwin && ios
     4  // +build darwin,ios
     5  
     6  package app
     7  
     8  /*
     9  #cgo CFLAGS: -Werror -fmodules -fobjc-arc -x objective-c
    10  
    11  @import Foundation;
    12  
    13  static void nslog(char *str) {
    14  	NSLog(@"%@", @(str));
    15  }
    16  */
    17  import "C"
    18  
    19  import (
    20  	"bufio"
    21  	"io"
    22  	"log"
    23  	"unsafe"
    24  
    25  	_ "gioui.org/internal/cocoainit"
    26  )
    27  
    28  func init() {
    29  	// macOS Console already includes timestamps.
    30  	log.SetFlags(log.Flags() &^ log.LstdFlags)
    31  	log.SetOutput(newNSLogWriter())
    32  }
    33  
    34  func newNSLogWriter() io.Writer {
    35  	r, w := io.Pipe()
    36  	go func() {
    37  		// 1024 is an arbitrary truncation limit, taken from Android's
    38  		// log buffer size.
    39  		lineBuf := bufio.NewReaderSize(r, 1024)
    40  		// The buffer to pass to C, including the terminating '\0'.
    41  		buf := make([]byte, lineBuf.Size()+1)
    42  		cbuf := (*C.char)(unsafe.Pointer(&buf[0]))
    43  		for {
    44  			line, _, err := lineBuf.ReadLine()
    45  			if err != nil {
    46  				break
    47  			}
    48  			copy(buf, line)
    49  			buf[len(line)] = 0
    50  			C.nslog(cbuf)
    51  		}
    52  	}()
    53  	return w
    54  }