- FIXED: All Python filters are executed with the same Python

  interpreter that executes the asciidoc parent (previously filters
  were hardwired to execute the 'python' interpreter). This prevents
  Python mixups (see http://groups.google.com/group/asciidoc/browse_thread/thread/14e8fcb289a135b/3af3b4e57b827c78?lnk=gst&q=archlinux#3af3b4e57b827c78

- FIXED: Leaky file handles in a2x and music and latex filters which
  created incompatibility problems for Jython. See
http://stackoverflow.com/questions/1832528/is-close-necessary-when-using-iterator-on-a-python-file-object

- FIXED: Jython AsciiDoc API (asciidocapi.py) StringIO incompatibility.

There is still an outstanding Jython related asciidocapi bug that
occurs when using a cStringIO output file: Jython throws an error when
non-ascii characters are found in included CSS or JavaScript files
(e.g. slidy.css), this only happens if you are executing asciidoc via
the asciidocapi and you are using a StringIO output file (as opposed
to a real file).

10 files changed, 129 insertions, 57 deletions

diff --git a/a2x.py b/a2x.py
index 83cfbec..498d729 100755
--- a/a2x.py
+++ b/a2x.py
@@ -144,6 +144,20 @@ def find_executable(file_name):
         result = _find_executable(file_name)
     return result
 
+def write_file(filename, data, mode='w'):
+    f = open(filename, mode)
+    try:
+        f.write(data)
+    finally:
+        f.close()
+
+def read_file(filename, mode='r'):
+    f = open(filename, mode)
+    try:
+        return f.read()
+    finally:
+        f.close()
+
 def shell_cd(path):
     verbose('chdir %s' % path)
     if not OPTIONS.dry_run:
@@ -236,19 +250,20 @@ def find_resources(files, tagname, attrname, filter=None):
     if isinstance(files, str):
         files = [files]
     result = []
-    for f in files:
-        verbose('finding resources in: %s' % f)
+    for filename in files:
+        verbose('finding resources in: %s' % filename)
         if OPTIONS.dry_run:
             continue
         parser = FindResources()
         # HTMLParser has problems with non-ASCII strings.
         # See http://bugs.python.org/issue3932
-        mo = re.search(r'^<\?xml.* encoding="(.*?)"', open(f).readline())
+        contents = read_file(filename)
+        mo = re.search(r'\A<\?xml.* encoding="(.*?)"', contents)
         if mo:
             encoding = mo.group(1)
-            parser.feed(open(f).read().decode(encoding))
+            parser.feed(contents.decode(encoding))
         else:
-            parser.feed(open(f).read())
+            parser.feed(contents)
         parser.close()
     result = list(set(result))   # Drop duplicate values.
     result.sort()
@@ -259,12 +274,12 @@ def copy_files(files, src_dir, dst_dir):
     '''
     Copy list of relative file names from src_dir to dst_dir.
     '''
-    for f in files:
-        f = os.path.normpath(f)
-        if os.path.isabs(f):
+    for filename in files:
+        filename = os.path.normpath(filename)
+        if os.path.isabs(filename):
             continue
-        src = os.path.join(src_dir, f)
-        dst = os.path.join(dst_dir, f)
+        src = os.path.join(src_dir, filename)
+        dst = os.path.join(dst_dir, filename)
         if not os.path.exists(dst):
             if not os.path.isfile(src):
                 warning('missing file: %s' % src)
@@ -323,10 +338,14 @@ def get_source_options(asciidoc_file):
     result = []
     if os.path.isfile(asciidoc_file):
         options = ''
-        for line in open(asciidoc_file):
-            mo = re.search(r'^//\s*a2x:', line)
-            if mo:
-                options += ' ' + line[mo.end():].strip()
+        f = open(asciidoc_file)
+        try:
+            for line in f:
+                mo = re.search(r'^//\s*a2x:', line)
+                if mo:
+                    options += ' ' + line[mo.end():].strip()
+        finally:
+            f.close()
         parse_options()
     return result
 
@@ -435,8 +454,12 @@ class A2X(AttrDict):
         if self.resource_manifest:
             if not os.path.isfile(self.resource_manifest):
                 die('missing --resource-manifest: %s' % self.resource_manifest)
-            for r in open(self.resource_manifest):
-                self.resources.append(r.strip())
+            f = open(self.resource_manifest)
+            try:
+                for r in f:
+                    self.resources.append(r.strip())
+            finally:
+                f.close()
         for r in self.resources:
             r = os.path.expanduser(r)
             r = os.path.expandvars(r)
@@ -710,7 +733,7 @@ class A2X(AttrDict):
                     f = os.path.normpath(f)
                     if f not in ['content.opf']:
                         resource_files.append(f)
-        opf = xml.dom.minidom.parseString(open(opf_file).read())
+        opf = xml.dom.minidom.parseString(read_file(opf_file))
         manifest_files = []
         manifest = opf.getElementsByTagName('manifest')[0]
         for el in manifest.getElementsByTagName('item'):
@@ -731,7 +754,7 @@ class A2X(AttrDict):
                 item.setAttribute('media-type', mimetype)
                 manifest.appendChild(item)
         if count > 0:
-            open(opf_file, 'w').write(opf.toxml())
+            write_file(opf_file, opf.toxml())
 
     def to_epub(self):
         self.to_docbook()
@@ -763,7 +786,7 @@ class A2X(AttrDict):
                 try:
                     # Create and add uncompressed mimetype file.
                     verbose('archiving: mimetype')
-                    open('mimetype','w').write('application/epub+zip')
+                    write_file('mimetype', 'application/epub+zip')
                     zip.write('mimetype', compress_type=zipfile.ZIP_STORED)
                     # Compress all remaining files.
                     for (p,dirs,files) in os.walk('.'):
diff --git a/asciidoc.conf b/asciidoc.conf
index 45a3be2..03c0934 100644
--- a/asciidoc.conf
+++ b/asciidoc.conf
@@ -519,7 +519,7 @@ emphasis-style=tags="emphasis"
 strong-style=tags="strong"
 monospaced-style=tags="monospaced"
 header-style=tags="header"
-asciidoc-style=tags="asciidoc",subs=(),filter='python "{asciidoc-file}" -b {backend} {asciidoc-args}{lang? -a "lang={lang}@"}{icons? -a icons -a "iconsdir={iconsdir}"}{imagesdir? -a "imagesdir={imagesdir}"}{data-uri? -a data-uri} -a "indir={indir}"{trace? -a "trace={trace}"}{blockname? -a "blockname={blockname}"} -s -'
+asciidoc-style=tags="asciidoc",subs=(),filter='"{python}" "{asciidoc-file}" -b {backend} {asciidoc-args}{lang? -a "lang={lang}@"}{icons? -a icons -a "iconsdir={iconsdir}"}{imagesdir? -a "imagesdir={imagesdir}"}{data-uri? -a data-uri} -a "indir={indir}"{trace? -a "trace={trace}"}{blockname? -a "blockname={blockname}"} -s -'
 
 [tabledef-nested]
 # Same as [tabledef-default] but with different delimiter and separator.
@@ -533,7 +533,7 @@ emphasis-style=tags="emphasis"
 strong-style=tags="strong"
 monospaced-style=tags="monospaced"
 header-style=tags="header"
-asciidoc-style=tags="asciidoc",subs=(),filter='python "{asciidoc-file}" -b {backend} {asciidoc-args}{lang? -a "lang={lang}@"}{icons? -a icons -a "iconsdir={iconsdir}"}{imagesdir? -a "imagesdir={imagesdir}"}{data-uri? -a data-uri} -a "indir={indir}"{trace? -a "trace={trace}"}{blockname? -a "blockname={blockname}"} -s -'
+asciidoc-style=tags="asciidoc",subs=(),filter='"{python}" "{asciidoc-file}" -b {backend} {asciidoc-args}{lang? -a "lang={lang}@"}{icons? -a icons -a "iconsdir={iconsdir}"}{imagesdir? -a "imagesdir={imagesdir}"}{data-uri? -a data-uri} -a "indir={indir}"{trace? -a "trace={trace}"}{blockname? -a "blockname={blockname}"} -s -'
 
 #----------------------------------------
 # Common block and macro markup templates
diff --git a/asciidoc.py b/asciidoc.py
index 953cae0..1b516be 100755
--- a/asciidoc.py
+++ b/asciidoc.py
@@ -799,14 +799,13 @@ def filter_lines(filter_cmd, lines, attrs={}):
             message.warning('filter not found: %s' % cmd)
     if found:
         filter_cmd = '"' + found + '"' + mo.group('tail')
-    if sys.platform == 'win32':
-        # Windows doesn't like running scripts directly so explicitly
-        # specify interpreter.
-        if found:
-            if cmd.endswith('.py'):
-                filter_cmd = 'python ' + filter_cmd
-            elif cmd.endswith('.rb'):
-                filter_cmd = 'ruby ' + filter_cmd
+    if found:
+        if cmd.endswith('.py'):
+            filter_cmd = '"%s" %s' % (document.attributes['python'],
+                filter_cmd)
+        elif cmd.endswith('.rb'):
+            filter_cmd = 'ruby ' + filter_cmd
+
     message.verbose('filtering: ' + filter_cmd)
     try:
         p = subprocess.Popen(filter_cmd, shell=True,
@@ -885,7 +884,11 @@ def system(name, args, is_macro=False, attrs=None):
                 message.warning('%s: non-zero exit status' % syntax)
             try:
                 if os.path.isfile(tmp):
-                    lines = [s.rstrip() for s in open(tmp)]
+                    f = open(tmp)
+                    try:
+                        lines = [s.rstrip() for s in f]
+                    finally:
+                        f.close()
                 else:
                     lines = []
             except Exception:
@@ -954,7 +957,11 @@ def system(name, args, is_macro=False, attrs=None):
         elif not is_safe_file(args):
             message.unsafe(syntax)
         else:
-            result = [s.rstrip() for s in open(args)]
+            f = open(args)
+            try:
+                result = [s.rstrip() for s in f]
+            finally:
+                f.close()
             if result:
                 result = subs_attrs(result)
                 result = separator.join(result)
@@ -2745,8 +2752,7 @@ class List(AbstractBlock):
         AbstractBlock.__init__(self)
         self.CONF_ENTRIES += ('type','tags')
         self.PARAM_NAMES += ('tags',)
-#ZZZ listdef?
-        # tabledef conf file parameters.
+        # listdef conf file parameters.
         self.type=None
         self.tags=None      # Name of listtags-<tags> conf section.
         # Calculated parameters.
@@ -4157,8 +4163,12 @@ class Reader1:
                                 message.verbose('include1: ' + fname, linenos=False)
                                 # Store the include file in memory for later
                                 # retrieval by the {include1:} system attribute.
-                                config.include1[fname] = [
-                                    s.rstrip() for s in open(fname)]
+                                f = open(fname)
+                                try:
+                                    config.include1[fname] = [
+                                        s.rstrip() for s in f]
+                                finally:
+                                    f.close()
                             return '{include1:%s}' % fname
                         else:
                             # This is a configuration dump, just pass the macro
@@ -5880,6 +5890,7 @@ def asciidoc(backend, doctype, confiles, infile, outfile, options):
                 else:
                     raise EAsciiDoc,'missing configuration file: %s' % f
     try:
+        document.attributes['python'] = sys.executable
         for f in config.filters:
             if not config.find_config_dir('filters', f):
                 raise EAsciiDoc,'missing filter: %s' % f
diff --git a/doc/asciidoc.txt b/doc/asciidoc.txt
index dadd961..20d02d9 100644
--- a/doc/asciidoc.txt
+++ b/doc/asciidoc.txt
@@ -4598,6 +4598,7 @@ predefined intrinsic attributes:
   {notitle}             do not display the document title
   {outdir}              document output directory name (note 2)
   {outfile}             output file name (note 2)
+  {python}              the full path name of the Python interpreter executable
   {rdquo}               Right double quote character (note 7)
   {reftext}             running block xreflabel generated by BlockId elements
   {revdate}             document revision date (from document header)
diff --git a/filters/latex/latex2png.py b/filters/latex/latex2png.py
index 65945a6..3cae7c9 100755
--- a/filters/latex/latex2png.py
+++ b/filters/latex/latex2png.py
@@ -90,6 +90,20 @@ def print_verbose(line):
     if verbose:
         print_stderr(line)
 
+def write_file(filename, data, mode='w'):
+    f = open(filename, mode)
+    try:
+        f.write(data)
+    finally:
+        f.close()
+
+def read_file(filename, mode='r'):
+    f = open(filename, mode)
+    try:
+        return f.read()
+    finally:
+        f.close()
+
 def run(cmd):
     global verbose
     if verbose:
@@ -117,12 +131,12 @@ def latex2png(infile, outfile, dpi, modified):
             checksum = md5.new(tex).digest()
             md5_file = os.path.splitext(outfile)[0] + '.md5'
             if os.path.isfile(md5_file) and os.path.isfile(outfile) and \
-                    checksum == open(md5_file,'rb').read():
+                    checksum == read_file(md5_file,'rb'):
                 skip = True
     else:
         if not os.path.isfile(infile):
             raise EApp, 'input file does not exist: %s' % infile
-        tex = open(infile).read()
+        tex = read_file(infile)
         if modified and os.path.isfile(outfile) and \
                 os.path.getmtime(infile) <= os.path.getmtime(outfile):
             skip = True
@@ -131,7 +145,7 @@ def latex2png(infile, outfile, dpi, modified):
         return
     tex = '%s\n%s\n%s\n' % (TEX_HEADER, tex.strip(), TEX_FOOTER)
     print_verbose('tex:\n%s' % tex)
-    open(texfile, 'w').write(tex)
+    write_file(texfile, tex)
     saved_pwd = os.getcwd()
     os.chdir(outdir)
     try:
@@ -152,7 +166,7 @@ def latex2png(infile, outfile, dpi, modified):
                 os.remove(f)
     if 'md5_file' in locals():
         print_verbose('writing: %s' % md5_file)
-        open(md5_file,'wb').write(checksum)
+        write_file(md5_file, checksum, 'wb')
 
 def usage(msg=''):
     if msg:
diff --git a/filters/music/music2png.py b/filters/music/music2png.py
index 9f1cda0..011cd1d 100755
--- a/filters/music/music2png.py
+++ b/filters/music/music2png.py
@@ -70,6 +70,20 @@ def print_verbose(line):
     if verbose:
         print_stderr(line)
 
+def write_file(filename, data, mode='w'):
+    f = open(filename, mode)
+    try:
+        f.write(data)
+    finally:
+        f.close()
+
+def read_file(filename, mode='r'):
+    f = open(filename, mode)
+    try:
+        return f.read()
+    finally:
+        f.close()
+
 def run(cmd):
     global verbose
     if not verbose:
@@ -90,19 +104,20 @@ def music2png(format, infile, outfile, modified):
     if infile == '-':
         source = sys.stdin.read()
         checksum = md5.new(source).digest()
-        f = os.path.splitext(outfile)[0] + '.md5'
+        filename = os.path.splitext(outfile)[0] + '.md5'
         if modified:
-            if os.path.isfile(f) and os.path.isfile(outfile) and \
-                    checksum == open(f,'rb').read():
+            if os.path.isfile(filename) and os.path.isfile(outfile) and \
+                    checksum == read_file(filename,'rb'):
                 skip = True
-            open(f,'wb').write(checksum)
+            else:
+                write_file(filename, checksum, 'wb')
     else:
         if not os.path.isfile(infile):
             raise EApp, 'input file does not exist: %s' % infile
         if modified and os.path.isfile(outfile) and \
                 os.path.getmtime(infile) <= os.path.getmtime(outfile):
             skip = True
-        source = open(infile).read()
+        source = read_file(infile)
     if skip:
         print_verbose('skipped: no change: %s' % outfile)
         return
@@ -111,7 +126,8 @@ def music2png(format, infile, outfile, modified):
             format = 'ly'
         else:
             format = 'abc'
-    open('%s.%s' % (basefile,format), 'w').write(source) # Temp source file.
+    # Write temporary source file.
+    write_file('%s.%s' % (basefile,format), source)
     abc = basefile + '.abc'
     ly = basefile + '.ly'
     png = basefile + '.png'
diff --git a/html5.conf b/html5.conf
index daeef7d..b463036 100644
--- a/html5.conf
+++ b/html5.conf
@@ -81,7 +81,7 @@ latexmath-style=template="latexmathblock",subs=()
 <a class="image" href="{link}">
 {data-uri%}<img src="{imagesdir=}{imagesdir?/}{target}" alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"}{title? title="{title}"}>
 {data-uri#}<img alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"}{title? title="{title}"} src="data:image/{eval:os.path.splitext(r'{target}')[1][1:]};base64,
-{data-uri#}{sys3:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}">
+{data-uri#}{sys3:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}">
 {link#}</a>
 </span>
 
@@ -91,7 +91,7 @@ latexmath-style=template="latexmathblock",subs=()
 <a class="image" href="{link}">
 {data-uri%}<img src="{imagesdir=}{imagesdir?/}{target}" alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"}>
 {data-uri#}<img alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"} src="data:image/{eval:os.path.splitext(r'{target}')[1][1:]};base64,
-{data-uri#}{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}">
+{data-uri#}{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}">
 {link#}</a>
 </div>
 <div class="title">{caption={figure-caption} {counter:figure-number}. }{title}</div>
@@ -150,7 +150,7 @@ ifndef::data-uri[]
 endif::data-uri[]
 ifdef::data-uri[]
 <img alt="{index}" src="data:image/png;base64,
-{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{index}.png}")}"}">
+{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{index}.png}")}"}">
 endif::data-uri[]
 endif::icons[]
 
@@ -213,7 +213,7 @@ ifndef::data-uri[]
 item=<tr><td><img src="{iconsdir}/callouts/{listindex}.png" alt="{listindex}"></td><td>|</td></tr>
 endif::data-uri[]
 ifdef::data-uri[]
-item=<tr><td><img alt="{listindex}" src="data:image/png;base64, {sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{listindex}.png}")}"}"></td><td>|</td></tr>
+item=<tr><td><img alt="{listindex}" src="data:image/png;base64, {sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{listindex}.png}")}"}"></td><td>|</td></tr>
 endif::data-uri[]
 text=|
 endif::icons[]
@@ -378,7 +378,7 @@ template::[quoteblock]
 <td class="icon">
 {data-uri%}{icons#}<img src="{icon={iconsdir}/{name}.png}" alt="{caption}">
 {data-uri#}{icons#}<img alt="{caption}" src="data:image/png;base64,
-{data-uri#}{icons#}{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/{name}.png}")}"}">
+{data-uri#}{icons#}{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/{name}.png}")}"}">
 {icons%}<div class="title">{caption}</div>
 </td>
 <td class="content">
diff --git a/tests/testasciidoc.py b/tests/testasciidoc.py
index aa185f1..679ad35 100755
--- a/tests/testasciidoc.py
+++ b/tests/testasciidoc.py
@@ -21,7 +21,14 @@ __version__ = '0.1.1'
 __copyright__ = 'Copyright (C) 2009 Stuart Rackham'
 
 
-import os, sys, re, StringIO, difflib
+import os, sys, re, difflib
+
+if sys.platform[:4] == 'java':
+    # Jython cStringIO is more compatible with CPython StringIO.
+    import cStringIO as StringIO
+else:
+    import StringIO
+
 import asciidocapi
 
 
diff --git a/xhtml11-quirks.conf b/xhtml11-quirks.conf
index c20376e..7c13366 100644
--- a/xhtml11-quirks.conf
+++ b/xhtml11-quirks.conf
@@ -10,7 +10,7 @@
 <a class="image" href="{link}">
 {data-uri%}<img src="{imagesdir=}{imagesdir?/}{target}" alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"} />
 {data-uri#}<img alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"} src="data:image/{eval:os.path.splitext(r'{target}')[1][1:]};base64,
-{data-uri#}{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}" />
+{data-uri#}{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}" />
 {link#}</a>
 </div>
 <div class="image-title">{caption={figure-caption} {counter:figure-number}: }{title}</div>
diff --git a/xhtml11.conf b/xhtml11.conf
index ce5fa19..c1ebb91 100644
--- a/xhtml11.conf
+++ b/xhtml11.conf
@@ -80,7 +80,7 @@ latexmath-style=template="latexmathblock",subs=()
 <a class="image" href="{link}">
 {data-uri%}<img src="{imagesdir=}{imagesdir?/}{target}" alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"}{title? title="{title}"} />
 {data-uri#}<img alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"}{title? title="{title}"} src="data:image/{eval:os.path.splitext(r'{target}')[1][1:]};base64,
-{data-uri#}{sys3:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}" />
+{data-uri#}{sys3:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}" />
 {link#}</a>
 </span>
 
@@ -90,7 +90,7 @@ latexmath-style=template="latexmathblock",subs=()
 <a class="image" href="{link}">
 {data-uri%}<img src="{imagesdir=}{imagesdir?/}{target}" alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"} />
 {data-uri#}<img alt="{alt={target}}"{width? width="{width}"}{height? height="{height}"} src="data:image/{eval:os.path.splitext(r'{target}')[1][1:]};base64,
-{data-uri#}{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}" />
+{data-uri#}{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{imagesdir=}",r"{target}")}"}" />
 {link#}</a>
 </div>
 <div class="title">{caption={figure-caption} {counter:figure-number}. }{title}</div>
@@ -131,7 +131,7 @@ ifndef::data-uri[]
 endif::data-uri[]
 ifdef::data-uri[]
 <img alt="{index}" src="data:image/png;base64,
-{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{index}.png}")}"}" />
+{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{index}.png}")}"}" />
 endif::data-uri[]
 endif::icons[]
 
@@ -194,7 +194,7 @@ ifndef::data-uri[]
 item=<tr><td><img src="{iconsdir}/callouts/{listindex}.png" alt="{listindex}" /></td><td>|</td></tr>
 endif::data-uri[]
 ifdef::data-uri[]
-item=<tr><td><img alt="{listindex}" src="data:image/png;base64, {sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{listindex}.png}")}"}" /></td><td>|</td></tr>
+item=<tr><td><img alt="{listindex}" src="data:image/png;base64, {sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/callouts/{listindex}.png}")}"}" /></td><td>|</td></tr>
 endif::data-uri[]
 text=|
 endif::icons[]
@@ -359,7 +359,7 @@ template::[quoteblock]
 <td class="icon">
 {data-uri%}{icons#}<img src="{icon={iconsdir}/{name}.png}" alt="{caption}" />
 {data-uri#}{icons#}<img alt="{caption}" src="data:image/png;base64,
-{data-uri#}{icons#}{sys:python -uc "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/{name}.png}")}"}" />
+{data-uri#}{icons#}{sys:"{python}" -u -c "import base64,sys; base64.encode(sys.stdin,sys.stdout)" < "{eval:os.path.join(r"{indir={outdir}}",r"{icon={iconsdir}/{name}.png}")}"}" />
 {icons%}<div class="title">{caption}</div>
 </td>
 <td class="content">