Now executing the backend.

git-svn-id: http://svn.complang.org/ragel/trunk@315 052ea7fc-9027-0410-9066-f65837a77df0

diff --git a/ragel/main.cpp b/ragel/main.cpp
index 11b9659..328b671 100644 (file)
--- a/ragel/main.cpp
+++ b/ragel/main.cpp
@@ -26,6 +26,12 @@
 #include <fstream>
 #include <unistd.h>
 #include <sstream>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
 
 /* Parsing. */
 #include "ragel.h"
@@ -45,6 +51,8 @@ using std::cin;
 using std::cout;
 using std::cerr;
 using std::endl;
+using std::ios;
+using std::streamsize;
 
 /* Controls minimization. */
 MinimizeLevel minimizeLevel = MinimizePartition2;
@@ -56,6 +64,9 @@ bool machineSpecFound = false;
 
 bool printStatistics = false;
 
+typedef Vector<char*> ArgsVector;
+ArgsVector backendArgs;
+
 /* Print a summary of the options. */
 void usage()
 {
@@ -169,7 +180,7 @@ char **makePathChecks( const char *argv0, const char *progName )
 }
 
 
-void execBackend( const char *argv0 )
+void execBackend( const char *argv0, costream *intermed )
 {
        /* Locate the backend program */
        const char *progName = 0;
@@ -187,9 +198,93 @@ void execBackend( const char *argv0 )
        }
 
        char **pathChecks = makePathChecks( argv0, progName );
-       while ( *pathChecks != 0 ) {
-               pathChecks += 1;
+
+       backendArgs.insert( 0, "rlgen-ruby" );
+       backendArgs.append( intermed->b->fileName );
+       backendArgs.append( 0 );
+
+       pid_t pid = fork();
+       if ( pid < 0 ) {
+               /* Error, no child created. */
+               error() << "failed to fork backend" << endp;
+       }
+       else if ( pid == 0 ) {
+               /* child */
+               while ( *pathChecks != 0 ) {
+                       execv( *pathChecks, backendArgs.data );
+                       pathChecks += 1;
+               }
+               error() << "failed to exec backend" << endp;
+       }
+       else {
+               /* parent. */
+               wait( 0 );
+       }
+
+       unlink( intermed->b->fileName );
+}
+
+char *makeIntermedTemplate( char *baseFileName )
+{
+       char *result;
+       char *lastSlash = strrchr( baseFileName, '/' );
+       if ( lastSlash == 0 ) {
+               result = new char[13];
+               strcpy( result, "ragel-XXXXXX.xml" );
+       }
+       else {
+               int baseLen = lastSlash - baseFileName + 1;
+               result = new char[baseLen + 13];
+               memcpy( result, baseFileName, baseLen );
+               strcpy( result+baseLen, "ragel-XXXXXX.xml" );
+       }
+       return result;
+};
+
+char fnChars[] = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+costream *openIntermed( char *inputFileName, char *outputFileName )
+{
+       srandom(time(0));
+       costream *result = 0;
+
+       /* Which filename do we use as the base? */
+       char *baseFileName = outputFileName != 0 ? outputFileName : inputFileName;
+
+       /* The template for the intermediate file name. */
+       char *intermedFileName = makeIntermedTemplate( baseFileName );
+
+       /* Randomize the name and try to open. */
+       char *firstX = strrchr( intermedFileName, 'X' ) - 5;
+       for ( int tries = 0; tries < 20; tries++ ) {
+               /* Choose a random name. */
+               for ( int x = 0; x < 6; x++ )
+                       firstX[x] = fnChars[random() % 52];
+
+               /* Try to open the file. */
+               int fd = ::open( intermedFileName, O_WRONLY|O_EXCL|O_CREAT, S_IRUSR|S_IWUSR );
+
+               if ( fd > 0 ) {
+                       /* Success. */
+                       FILE *file = fdopen( fd, "wt" );
+                       if ( file == 0 )
+                               error() << "fdopen(...) on intermediate file failed" << endp;
+
+                       cfilebuf *b = new cfilebuf( intermedFileName, file );
+                       result = new costream( b );
+                       break;
+               }
+
+               if ( errno == EACCES ) {
+                       error() << "failed to open temp file " << intermedFileName << 
+                                       ", access denied" << endp;
+               }
        }
+
+       if ( result == 0 )
+               error() << "abnormal error: cannot find unique name for temp file" << endp;
+
+       return result;
 }
 
 /* Main, process args and call yyparse to start scanning input. */
@@ -212,6 +307,8 @@ int main(int argc, char **argv)
                                else {
                                        /* Ok, remember the output file name. */
                                        outputFileName = pc.parameterArg;
+                                       backendArgs.append( "-o" );
+                                       backendArgs.append( pc.parameterArg );
                                }
                                break;
 
@@ -332,7 +429,7 @@ int main(int argc, char **argv)
                        strcmp( inputFileName, outputFileName  ) == 0 )
        {
                error() << "output file \"" << outputFileName  << 
-                               "\" is the same as the input file" << endl;
+                               "\" is the same as the input file" << endp;
        }
 
        /* Open the input file for reading. */
@@ -342,24 +439,20 @@ int main(int argc, char **argv)
                ifstream *inFile = new ifstream( inputFileName );
                inStream = inFile;
                if ( ! inFile->is_open() )
-                       error() << "could not open " << inputFileName << " for reading" << endl;
+                       error() << "could not open " << inputFileName << " for reading" << endp;
        }
        else {
                inputFileName = "<stdin>";
                inStream = &cin;
        }
 
-
-       /* Bail on above errors. */
-       if ( gblErrorCount > 0 )
-               exit(1);
-
-       std::ostringstream outputBuffer;
+       /* Used for just a few things. */
+       std::ostringstream hostData;
 
        if ( machineSpec == 0 && machineName == 0 )
-               outputBuffer << "<host line=\"1\" col=\"1\">";
+               hostData << "<host line=\"1\" col=\"1\">";
 
-       Scanner scanner( inputFileName, *inStream, outputBuffer, 0, 0, 0, false );
+       Scanner scanner( inputFileName, *inStream, hostData, 0, 0, 0, false );
        scanner.do_scan();
 
        /* Finished, final check for errors.. */
@@ -374,24 +467,21 @@ int main(int argc, char **argv)
                return 1;
 
        if ( machineSpec == 0 && machineName == 0 )
-               outputBuffer << "</host>\n";
+               hostData << "</host>\n";
 
        if ( gblErrorCount > 0 )
                return 1;
        
-       ostream *outputFile = 0;
-       if ( outputFileName != 0 )
-               outputFile = new ofstream( outputFileName );
-       else
-               outputFile = &cout;
+       costream *intermed = openIntermed( inputFileName, outputFileName );
 
        /* Write the machines, then the surrounding code. */
-       writeMachines( *outputFile, outputBuffer.str(), inputFileName );
+       writeMachines( *intermed, hostData.str(), inputFileName );
 
-       if ( outputFileName != 0 )
-               delete outputFile;
+       /* Close the intermediate file. */
+       intermed->fclose();
 
-       execBackend( argv[0] );
+       /* Run the backend process. */
+       execBackend( argv[0], intermed );
 
        return 0;
 }