handle absolute paths in file preloading

3 files changed, 31 insertions, 19 deletions

diff --git a/emcc b/emcc
index eeb8fd7b..39918e22 100755
--- a/emcc
+++ b/emcc
@@ -906,7 +906,8 @@ try:
     partial_dirs = []
     for file_ in data_files:
       dirname = os.path.dirname(file_['name'])
-      if dirname != '' and dirname != '/':
+      dirname = dirname.lstrip('/') # absolute paths start with '/', remove that
+      if dirname != '':
         parts = dirname.split('/')
         for i in range(len(parts)):
           partial = '/'.join(parts[:i+1])
diff --git a/src/library.js b/src/library.js
index fdb5e7e6..290f71f2 100644
--- a/src/library.js
+++ b/src/library.js
@@ -371,8 +371,10 @@ LibraryManager.library = {
       if (!error.printer) error.printer = Module['print'];
       if (!error.buffer) error.buffer = [];
 
-      // Create the temporary folder.
-      FS.createFolder('/', 'tmp', true, true);
+      // Create the temporary folder, if not already created
+      try {
+        FS.createFolder('/', 'tmp', true, true);
+      } catch(e) {}
 
       // Create the I/O devices.
       var devFolder = FS.createFolder('/', 'dev', true, true);
diff --git a/tests/runner.py b/tests/runner.py
index 2dbcb760..b8cbc588 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -6923,27 +6923,36 @@ elif 'browser' in str(sys.argv):
 
     def test_preload_file(self):
       open(os.path.join(self.get_dir(), 'somefile.txt'), 'w').write('''load me right before running the code please''')
-      open(os.path.join(self.get_dir(), 'main.cpp'), 'w').write(self.with_report_result(r'''
-        #include <stdio.h>
-        #include <string.h>
-        #include <emscripten.h>
-        int main() {
-          FILE *f = fopen("somefile.txt", "r");
-          char buf[100];
-          fread(buf, 1, 20, f);
-          buf[20] = 0;
-          fclose(f);
-          printf("|%s|\n", buf);
+      def make_main(path):
+        print path
+        open(os.path.join(self.get_dir(), 'main.cpp'), 'w').write(self.with_report_result(r'''
+          #include <stdio.h>
+          #include <string.h>
+          #include <emscripten.h>
+          int main() {
+            FILE *f = fopen("%s", "r");
+            char buf[100];
+            fread(buf, 1, 20, f);
+            buf[20] = 0;
+            fclose(f);
+            printf("|%%s|\n", buf);
 
-          int result = !strcmp("load me right before", buf);
-          REPORT_RESULT();
-          return 0;
-        }
-      '''))
+            int result = !strcmp("load me right before", buf);
+            REPORT_RESULT();
+            return 0;
+          }
+        ''' % path))
 
+      make_main('somefile.txt')
       Popen(['python', EMCC, os.path.join(self.get_dir(), 'main.cpp'), '--preload-file', 'somefile.txt', '-o', 'page.html']).communicate()
       self.run_browser('page.html', 'You should see |load me right before|.', '/report_result?1')
 
+      # By absolute path
+
+      make_main(os.path.join(self.get_dir(), 'somefile.txt'))
+      Popen(['python', EMCC, os.path.join(self.get_dir(), 'main.cpp'), '--preload-file', os.path.join(self.get_dir(), 'somefile.txt'), '-o', 'page.html']).communicate()
+      self.run_browser('page.html', 'You should see |load me right before|.', '/report_result?1')
+
     def test_multifile(self):
       # a few files inside a directory
       self.clear()