Add argument to -m flag to specify the output directory for multi fil…

…e output.

BUILD

@@ -14,6 +14,8 @@ genrule(
           "echo >> $@",
 )
 
+# TODO(dzc): Remove the includes = ["."] lines from all cc_* targets once
+# bazelbuild/bazel#445 is fixed.
 cc_library(
     name = "jsonnet-common",
     srcs = [
@@ -30,31 +32,36 @@ cc_library(
         "static_error.h",
         "vm.h",
     ],
+    includes = ["."],
 )
 
 cc_library(
     name = "libjsonnet",
     srcs = ["libjsonnet.cpp"],
     hdrs = ["libjsonnet.h"],
     deps = [":jsonnet-common"],
+    includes = ["."],
 )
 
 cc_binary(
     name = "jsonnet",
     srcs = ["jsonnet.cpp"],
     deps = [":libjsonnet"],
+    includes = ["."],
 )
 
 cc_binary(
     name = "libjsonnet_test_snippet",
     srcs = ["libjsonnet_test_snippet.c"],
     deps = [":libjsonnet"],
+    includes = ["."],
 )
 
 cc_binary(
     name = "libjsonnet_test_file",
     srcs = ["libjsonnet_test_file.c"],
     deps = [":libjsonnet"],
+    includes = ["."],
 )
 
 filegroup(

jsonnet.cpp

@@ -81,7 +81,7 @@ static enum ImportStatus try_path(const std::string &dir, const std::string &rel
 }
 
 static char *from_string(JsonnetVm* vm, const std::string &v)
-{   
+{
     char *r = jsonnet_realloc(vm, nullptr, v.length() + 1);
     std::strcpy(r, v.c_str());
     return r;
@@ -177,7 +177,7 @@ void usage(std::ostream &o)
     o << "  --code-var <var>=<val>  As --var but value is Jsonnet code\n";
     o << "  --code-env <var>        As --env but env var contains Jsonnet code\n";
     o << "  -o / --output-file <file> Write to the output file rather than stdout\n";
-    o << "  -m / --multi            Write multiple files, list files on stdout\n";
+    o << "  -m / --multi <dir>      Write multiple files to the directory, list files on stdout\n";
     o << "  -S / --string           Expect a string, manifest as plain text\n";
     o << "  -s / --max-stack <n>    Number of allowed stack frames\n";
     o << "  -t / --max-trace <n>    Max length of stack trace before cropping\n";
@@ -239,8 +239,9 @@ int main(int argc, const char **argv)
 
         JsonnetVm *vm = jsonnet_make();
         bool filename_is_code = false;
-            
+
         bool multi = false;
+        std::string output_dir = ".";
 
         auto args = simplify_args(argc, argv);
         std::vector<std::string> remaining_args;
@@ -347,12 +348,21 @@ int main(int argc, const char **argv)
                 filename_is_code = true;
             } else if (arg == "-m" || arg == "--multi") {
                 multi = true;
+                std::string dir = next_arg(i, args);
+                if (dir.length() == 0) {
+                    std::cerr << "ERROR: -m argument was empty string" << std::endl;
+                    return EXIT_FAILURE;
+                }
+                if (dir[dir.length() - 1] != '/') {
+                    dir += '/';
+                }
+                output_dir = dir;
             } else if (arg == "-o" || arg == "--output-file") {
-              output_file = next_arg(i, args);
-              if (output_file.length() == 0) {
-                  std::cerr << "ERROR: -o output was empty string" << std::endl;
-                  return EXIT_FAILURE;
-              }
+                output_file = next_arg(i, args);
+                if (output_file.length() == 0) {
+                    std::cerr << "ERROR: -o output was empty string" << std::endl;
+                    return EXIT_FAILURE;
+                }
             } else if (arg == "-S" || arg == "--string") {
                 jsonnet_string_output(vm, 1);
             } else if (arg == "--debug-ast") {
@@ -431,6 +441,9 @@ int main(int argc, const char **argv)
             return EXIT_FAILURE;
         }
 
+        // If multiple file output is used, then iterate over each string from
+        // the sequence of strings returned by jsonnet_evaluate_snippet_multi,
+        // construct pairs of filename and content, and write each output file.
         if (multi) {
             std::map<std::string, std::string> r;
             for (const char *c=output ; *c!='\0' ; ) {
@@ -447,7 +460,7 @@ int main(int argc, const char **argv)
             jsonnet_realloc(vm, output, 0);
             for (const auto &pair : r) {
                 const std::string &new_content = pair.second;
-                const std::string &filename = pair.first;
+                const std::string &filename = output_dir + pair.first;
                 std::cout << filename << std::endl;
                 {
                     std::ifstream exists(filename.c_str());