[pdf-devel] Logging function

[Aleksander Morgado]

Hi all,

I am thinking in preparing a simple logging function to be used mostly 
for development and debugging purposes. It would allow to enable at 
configure level not only the level of debug wanted, but also which 
modules should have the logging enabled.

For example,
./configure --enable-log-base-text --with-log-level=debug
Would enable log level DEBUG in the Text Module of the Base layer

./configure --enable-log-object-reader --enable-log-object-writer 
--with-log-level=info
Would enable log level INFO in the Reader and Writer Modules of the 
Object layer

./configure --enable-log-base-all --with-log-level=warning
Would enable log level WARNING in All the modules of the Base layer


The API would be something like this:

/* Enumeration of log types (only for Base layer modules yet) */
enum pdf_log_type_e {
  PDF_LOG_TYPE_BASE_MEMORY      = 0,
  PDF_LOG_TYPE_BASE_BASICTYPES  = 1,
  PDF_LOG_TYPE_BASE_HASH        = 2,
  PDF_LOG_TYPE_BASE_LIST        = 3,
  PDF_LOG_TYPE_BASE_STREAM      = 4,
  PDF_LOG_TYPE_BASE_FLOAT       = 5,
  PDF_LOG_TYPE_BASE_TEXT        = 6,
  PDF_LOG_TYPE_BASE_TIME        = 7,
  PDF_LOG_TYPE_BASE_FILESYSTEM  = 8,
  PDF_LOG_TYPE_BASE_ERROR       = 9,
  PDF_LOG_TYPE_MAX
};

/* Enumeration of log levels */
enum pdf_log_level_e {
  PDF_LOG_LEVEL_DEBUG   = 0,
  PDF_LOG_LEVEL_INFO    = 1,
  PDF_LOG_LEVEL_WARNING = 2,
  PDF_LOG_LEVEL_ERROR   = 3,
  PDF_LOG_LEVEL_NONE    = 4
};

/* Main logging function */
void pdf_log(enum pdf_log_level_e log_level,
             enum pdf_log_type_e  log_type,
             const char           *str_template,
             ...);


So that, for example, the Text module can call the logging function in 
this way:

pdf_log(PDF_LOG_LEVEL_WARNING, PDF_LOG_TYPE_BASE_TEXT, \
        "Invalid %s point found at index '%u'", \
        encoding, position);

The message will be dumped to stderr only if `--enable-log-base-text' 
was used when calling configure, and if at least `warning' level was 
selected in `--with-log-level'.

The output would be something like:
[GNU PDF Warning] (Base-Text) Invalid UTF-16BE point found at index '8'



What do you think?


Aleksander