libcupsfilters: Added filterTee() filter function for debugging

This filter function is mainly for debugging. it resembles the "tee"
utility, passing through the data unfiltered and copying it to a
file. The file name is simply given as parameter. This makes using the
function easy (add it as item of a filter chain called via
filterChain()) and can even be used more than once in the same filter
chain (using different file names).

In case of write error to the copy file, copying is stopped but the
rest of the job is passed on to the next filter. If NULL is supplied
as file name, the data is simply passed through without getting
copied.

diff --git a/cupsfilters/filter.c b/cupsfilters/filter.c
index 5700ea0a8f6d17726ecef8332359a279080cd914..b12ac62ccc5da860510b7a537f8fba681e51ba0f 100644 (file)
--- a/cupsfilters/filter.c
+++ b/cupsfilters/filter.c
@@ -230,6 +230,84 @@ filterCUPSWrapper(
 }
 
 
+/*
+ * 'filterTee()' - This filter function is mainly for debugging. it
+ *                 resembles the "tee" utility, passing through the
+ *                 data unfiltered and copying it to a file. The file
+ *                 name is simply given as parameter. This makes using
+ *                 the function easy (add it as item of a filter chain
+ *                 called via filterChain()) and can even be used more
+ *                 than once in the same filter chain (using different
+ *                 file names). In case of write error to the copy
+ *                 file, copying is stopped but the rest of the job is
+ *                 passed on to the next filter. If NULL is supplied
+ *                 as file name, the data is simply passed through
+ *                 without getting copied.
+ */
+
+int                            /* O - Error status */
+filterTee(int inputfd,         /* I - File descriptor input stream */
+         int outputfd,        /* I - File descriptor output stream */
+         int inputseekable,   /* I - Is input stream seekable? (unused) */
+         filter_data_t *data, /* I - Job and printer data */
+         void *parameters)    /* I - Filter-specific parameters (File name) */
+{
+  const char           *filename = (const char *)parameters;
+  ssize_t             bytes, total = 0;      /* Bytes read/written */
+  char                buffer[65536];         /* Read/write buffer */
+  filter_logfunc_t     log = data->logfunc;   /* Log function */
+  void                 *ld = data->logdata;   /* log function data */
+  int                  teefd = -1;            /* File descriptor for "tee"ed
+                                                 copy */
+
+
+  (void)inputseekable;
+
+  /* Open the "tee"ed copy file */
+  if (filename)
+    teefd = open(filename, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR);
+
+  while ((bytes = read(inputfd, buffer, sizeof(buffer))) > 0)
+  {
+    total += bytes;
+    if (log)
+      log(ld, FILTER_LOGLEVEL_DEBUG,
+         "filterTee (%s): Passing on%s %d bytes, total %d bytes.",
+         filename, teefd >= 0 ? " and copying" : "", bytes, total);
+
+    if (teefd >= 0)
+      if (write(teefd, buffer, (size_t)bytes) != bytes)
+      {
+       if (log)
+         log(ld, FILTER_LOGLEVEL_ERROR,
+             "filterTee (%s): Unable to write %d bytes to the copy, stopping copy, continuing job output.",
+             filename, (int)bytes);
+       close(teefd);
+       teefd = -1;
+      }
+
+    if (write(outputfd, buffer, (size_t)bytes) != bytes)
+    {
+      if (log)
+       log(ld, FILTER_LOGLEVEL_ERROR,
+           "filterTee (%s): Unable to pass on %d bytes.",
+           filename, (int)bytes);
+      if (teefd >= 0)
+       close(teefd);
+      close(inputfd);
+      close(outputfd);
+      return (1);
+    }
+  }
+
+  if (teefd >= 0)
+    close(teefd);
+  close(inputfd);
+  close(outputfd);
+  return (0);
+}
+
+
 /*
  * 'filterPOpen()' - Pipe a stream to or from a filter function
  *                   Can be the input to or the output from the

diff --git a/cupsfilters/filter.h b/cupsfilters/filter.h
index c871bdaa8bcfb6260bdc668728eb4547e423418d..8878f08821ba13f5082420c6595068306d6b89db 100644 (file)
--- a/cupsfilters/filter.h
+++ b/cupsfilters/filter.h
@@ -146,6 +146,15 @@ extern int filterCUPSWrapper(int argc,
                             int *JobCanceled);
 
 
+extern int filterTee(int inputfd,
+                    int outputfd,
+                    int inputseekable,
+                    filter_data_t *data,
+                    void *parameters);
+
+/* Parameters: Filename/path (const char *) to copy the data to */
+
+
 extern int filterPOpen(filter_function_t filter_func, /* I - Filter function */
                       int inputfd,
                       int outputfd,