Main: Run executables from the temporary directory.

As of May 2020, MiKTeX does no longer support short filenames (aka 8.3 filenames), so if the path to the temporary directory contains short filenames, LaTeX compilation will fail. Unfortunately, in the current framework it seems to be impossible to obtain the full path (with only long filenames) easily.

Resolve this by launching a shell that changes into the temporary directory and then calls the executable from there.

content/main.js

@@ -144,21 +144,7 @@ var tblatex = {
           };
         }
       }
-      var init_process = function(path) {
-        var process = Components.classes["@mozilla.org/process/util;1"].createInstance(Components.interfaces.nsIProcess);
-        process.init(path);
-        return process;
-      }
-      var sanitize_arg = function(arg) {
-        // on Windows the nsIProcess function will add quotes around all arguments with spaces for us
-        if (isWindows)
-          return arg;
-        else if (arg.indexOf(" ") < 0)
-          return arg;
-        else
-          return "\""+arg+"\"";
-      }
-
+
       var latex_bin = init_file(prefs.getCharPref("latex_path"));
       if (!latex_bin.exists()) {
         alert("Latex It! Error\n\nThe 'latex' executable cannot be found.\n\nSolution:\n\tSet the right path in the add-on's options dialog (☰>Add-ons>Latex It!)");
@@ -198,15 +184,46 @@ var tblatex = {
       // script file).
       // Here we get the shell binary and the command line option to call an
       // external program.
-      if (isWindows) {
-        var env = Components.classes["@mozilla.org/process/environment;1"]
-                  .getService(Components.interfaces.nsIEnvironment);
-        var shell_bin = init_file(env.get("COMSPEC"));
-        var shell_option = "/C";
-      } else {
-        var shell_bin = init_file("/bin/sh");
-        var shell_option = "-c";
-      }
+      //
+      // On all platforms, nsIProcess will escape the arguments, that is:
+      // - Escape backslashes (\) and double quotes (") with backslashes (\).
+      // - Wrap the argument in double quotes (") if it contains white-space.
+      // Unfortunately this produces arguments that are not compatible with
+      // Windows CMD. Work around this by adding echo statements in a cunning
+      // way.
+      const runShellCmdInDir = (dir, args) => {
+        const addQuotesIfWhitespace = (arg) => {
+          return arg.indexOf(" ") < 0 ? arg : "\"" + arg + "\"";
+        };
+        let dirQ = addQuotesIfWhitespace(dir);
+        let shellBin;
+        let shellArgs;
+        if (isWindows) {
+          let env = Cc["@mozilla.org/process/environment;1"]
+              .getService(Ci.nsIEnvironment);
+          shellBin = init_file(env.get("COMSPEC"));
+          // /c "echo " \" && cd /d <dir> && <args> && echo \"
+          shellArgs = ["/c", "echo ", "\"", "&&", "cd", "/d", dir, "&&",
+              ...args, "&&", "echo", "\""];
+        } else {
+          shellBin = init_file("/bin/sh");
+          let argsQ = args.map(addQuotesIfWhitespace).join(" ");
+          // -c "cd <dir> && <args>"
+          shellArgs = ["-c", "cd " + dirQ + " && " + argsQ];
+        }
+        let shellProcess = Cc["@mozilla.org/process/util;1"]
+            .createInstance(Ci.nsIProcess);
+        shellProcess.init(shellBin);
+        shellProcess.run(true, shellArgs, shellArgs.length);
+        let shellPathQ = addQuotesIfWhitespace(shellBin.path);
+        let argsQ = args.map(addQuotesIfWhitespace).join(" ");
+        let cmd = isWindows ?
+            shellPathQ + " /c \"cd /d " + dirQ + " && " + argsQ + "\"" :
+            shellPathQ + " -c 'cd " + dirQ + " && " + argsQ + "'";
+        log += "I ran (exit code " + shellProcess.exitValue + "):\n"
+            + cmd + "\n";
+        return shellProcess.exitValue;
+      };
 
       var temp_dir = Components.classes["@mozilla.org/file/directory_service;1"].
         getService(Components.interfaces.nsIProperties).
@@ -241,17 +258,15 @@ var tblatex = {
       converter.writeString(latex_expr);
       converter.close(); // this closes foStream
 
+      let exitValue = runShellCmdInDir(temp_dir, [
+        latex_bin.path,
+        "-interaction=batchmode",
+        temp_file_noext + ".tex"
+      ]);
 
-      var latex_process = init_process(latex_bin);
-      var latex_args = ["-output-directory="+temp_dir, "-interaction=batchmode", temp_file.path];
-      // This adds quotes around all arguments that contains spaces but only on Unix (on Windows the nsIProcess function will add quotes around all arguments with spaces for us)
-      latex_args = latex_args.map(sanitize_arg);
-      latex_process.run(true, latex_args, latex_args.length);
-      if (debug)
-        log += "I ran "+sanitize_arg(latex_bin.path)+" "+latex_args.join(" ")+" error code "+latex_process.exitValue+"\n";
-      if (latex_process.exitValue) {
+      if (exitValue) {
         st = 1;
-        log += "LaTeX process returned "+latex_process.exitValue+"\nProceeding anyway...\n";
+        log += "LaTeX process returned " + exitValue + "\nProceeding anyway...\n";
       }
 
       ["log", "aux"].forEach(function (ext) {
@@ -342,25 +357,24 @@ var tblatex = {
       if (debug)
         log += "*** Calculated resolution is "+dpi+" dpi\n";
 
-      var shell_process = init_process(shell_bin);
-      var dvipng_args = [dvipng_bin.path, "--depth", "-T", "tight", "-z", "3", "-bg", "Transparent", "-D", dpi.toString(), "-fg", font_color, "-o", png_file.path, dvi_file.path, ">", depth_file.path];
-      // This adds quotes around all arguments that contains spaces but only on Unix (on Windows the nsIProcess function will add quotes around all arguments with spaces for us)
-      dvipng_args = dvipng_args.map(sanitize_arg);
-      if (isWindows) {
-        // The additional echo commands are needed on Windows in order to remove the unwanded backslaches and quotes added by the nsIProcess function ( shell_process.run )
-        var prefix_args = ["echo ", "\"", "&"];
-        var suffix_args = ["&", "echo", "\""];
-        var process_args = [shell_option].concat(prefix_args, dvipng_args, suffix_args);
-      } else {
-        var process_args = [shell_option, dvipng_args.join(" ")];
-      }
-      shell_process.run(true, process_args, process_args.length);
+      exitValue = runShellCmdInDir(temp_dir, [
+        dvipng_bin.path,
+        "--depth",
+        "-D", dpi.toString(),
+        "-T", "tight",
+        "-fg", font_color,
+        "-bg", "Transparent",
+        "-z", "3",
+        "-o", temp_file_noext + ".png",
+        temp_file_noext + ".dvi",
+        ">", temp_file_noext + "-depth.txt"
+      ]);
+
       if (deletetempfiles) dvi_file.remove(false);
-      if (debug)
-        log += "I ran "+shell_bin.path+" -c '"+dvipng_args.join(" ")+"'\n";
-      if (shell_process.exitValue) {
-        // alert("Latex It! Error\n\nWhen converting the .dvi to a .png bitmap, 'dvipng' failed (Error code: "+shell_process.exitValue+")\n\nSolution:\n\tWe left the .dvi file there:\n\t\t"+temp_file.path+"\n\tTry to run 'dvipng --depth' on it by yourself...");
-        log += "!!! dvipng failed with error code "+shell_process.exitValue+". Aborting.\n";
+
+      if (exitValue) {
+        // alert("Latex It! Error\n\nWhen converting the .dvi to a .png bitmap, 'dvipng' failed (Error code: "+exitValue+")\n\nSolution:\n\tWe left the .dvi file there:\n\t\t"+temp_file.path+"\n\tTry to run 'dvipng --depth' on it by yourself...");
+        log += "!!! dvipng failed with error code " + exitValue + ". Aborting.\n";
         return [2, "", 0, log];
       }