Correctly handle nonexistent `spec.json` file.

include/config.h

@@ -14,11 +14,11 @@ struct Config {
 };
 
 enum ConfigError {
-  // Indicates the $CWD could not be retrieved.
+  // The $CWD could not be retrieved.
   CE_ENV_CWD_INVALID = 1,
-  // Indicates the $BOOTSTRAP_ROOT_DIR environment variable is empty.
+  // The $BOOTSTRAP_ROOT_DIR environment variable is empty.
   CE_ENV_ROOT_DIR_INVALID,
-  // Indicates the target argument is invalid.
+  // The target argument is invalid.
   CE_TARGET_INVALID,
 };
 

include/loader.h

@@ -0,0 +1,25 @@
+#ifndef _BOOTSTRAP_LOADER_H
+#define _BOOTSTRAP_LOADER_H
+
+#include "cJSON.h"
+#include "config.h"
+
+enum SpecJsonError {
+  // The `spec.json` file exists but cannot be open.
+  SJE_JSON_CANNOT_OPEN = 1,
+  // The JSON of the corresponding file is not syntactically valid JSON.
+  SJE_JSON_INVALID,
+};
+
+/*
+Reads in the `spec.json` file relative to the paths of the provided @Config.
+
+A spec directory does not necessarily contain a `spec.json` file. If this file
+cannot be found, the @parsed pointer is set to NULL with a success return code.
+
+@return: 0 on success and a @SpecJsonError otherwise.
+*/
+enum SpecJsonError
+read_spec_json(const struct Config *const config, cJSON **parsed);
+
+#endif /* _BOOTSTRAP_LOADER_H */

include/path.h

@@ -0,0 +1,8 @@
+#ifndef _BOOTSTRAP_PATH_H
+#define _BOOTSTRAP_PATH_H
+
+#include <stdlib.h>
+
+char *join_path_segments(size_t n, const char *segments[static n]);
+
+#endif /* _BOOTSTRAP_PATH_H */

main.c

@@ -2,8 +2,9 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+#include "cJSON.h"
 #include "config.h"
-#include "dyn_array.h"
+#include "loader.h"
 
 const char *ENV_BOOTSTRAP_ROOT_DIR = "BOOTSTRAP_ROOT_DIR";
 
@@ -15,24 +16,51 @@ int main(int argc, char **argv) {
     exit(EXIT_FAILURE);
   }
 
-  const char *cwd = getcwd(0, 0);
+  int retval = EXIT_SUCCESS;
+  char *cwd = getcwd(0, 0);
   const char *root_dir = getenv(ENV_BOOTSTRAP_ROOT_DIR);
   const char *target = argv[1];
 
+  // `cwd` must be free'd.
+
   struct Config *config = 0;
   switch (config_load(cwd, root_dir, target, &config)) {
   case CE_ENV_CWD_INVALID:
     fprintf(stderr, "Could not retrieve the $CWD value.");
-    exit(EXIT_FAILURE);
+    retval = EXIT_FAILURE;
+    goto cwd_cleanup;
   case CE_ENV_ROOT_DIR_INVALID:
     fprintf(stderr, "Must specify $BOOTSTRAP_ROOT_DIR environment variable.");
-    exit(EXIT_FAILURE);
+    retval = EXIT_FAILURE;
+    goto cwd_cleanup;
   case CE_TARGET_INVALID:
     fprintf(stderr, "Target spec `%s` is invalid.", argv[1]);
-    exit(EXIT_FAILURE);
+    retval = EXIT_FAILURE;
+    goto cwd_cleanup;
   }
 
+  // `config` must be free'd.
+
+  cJSON *parsed = 0;
+  switch (read_spec_json(config, &parsed)) {
+  case SJE_JSON_CANNOT_OPEN:
+    fprintf(stderr, "Found `spec.json` but could not open.");
+    retval = EXIT_FAILURE;
+    goto config_cleanup;
+  case SJE_JSON_INVALID:
+    fprintf(stderr, "`spec.json` does not conform to bootstrap format.");
+    retval = EXIT_FAILURE;
+    goto config_cleanup;
+  }
+
+  // TODO: Extract the prompts out of the `spec.json` file.
+  // TODO: Load in the curses interface.
+  // TODO: Run `run.sh`.
+
+config_cleanup:
   config_free(config);
-  free((void *)cwd);
-  return EXIT_SUCCESS;
+
+cwd_cleanup:
+  free(cwd);
+  return retval;
 }

src/loader.c

@@ -0,0 +1,48 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "loader.h"
+#include "path.h"
+
+/*
+Returns a file pointer to the `spec.json` file if it exists. Returns 0
+otherwise.
+*/
+static int find_spec_json(const struct Config *const config, FILE **handle) {
+  const char *segments[] = {config->root_dir, config->target, "spec.json"};
+  char *filepath =
+    join_path_segments(sizeof(segments) / sizeof(char *), segments);
+
+  int retval = 0;
+  // It is ok if the file does not exist. It is not ok if we couldn't open the
+  // file for any other reason.
+  *handle = fopen(filepath, "r");
+  if (!*handle && errno != ENOENT) {
+    retval = errno;
+  }
+
+  free(filepath);
+  return retval;
+}
+
+enum SpecJsonError
+read_spec_json(const struct Config *const config, cJSON **parsed) {
+  FILE *handle = 0;
+  int retval = find_spec_json(config, &handle);
+
+  if (retval != 0) {
+    return SJE_JSON_CANNOT_OPEN;
+  }
+
+  // The `spec.json` file does not exist.
+  if (!handle) {
+    *parsed = 0;
+    return 0;
+  }
+
+  // TODO: Need to parse the spec.json file.
+  fclose(handle);
+  assert(false);
+}

src/path.c

@@ -0,0 +1,28 @@
+#include <assert.h>
+#include <string.h>
+
+#include "path.h"
+
+char *join_path_segments(size_t n, const char *segments[static n]) {
+  assert(n > 0);
+
+  size_t length = 0;
+  for (int i = 0; i < n; ++i) {
+    length += strlen(segments[i]);
+  }
+  length += n - 1; // Path separators.
+
+  size_t offset = 0;
+  char *joined = calloc(1, length + 1);
+
+  for (int i = 0; i < n; ++i) {
+    const size_t segment_len = strlen(segments[i]);
+    memcpy(joined + offset, segments[i], segment_len);
+    offset += segment_len;
+    if (i < n - 1) {
+      joined[offset++] = '/';
+    }
+  }
+
+  return joined;
+}

test/runner.c

@@ -1,6 +1,8 @@
 #include "sput.h"
 #include "test_config.h"
 #include "test_dyn_array.h"
+#include "test_loader.h"
+#include "test_path.h"
 
 int main(int argc, char *argv[]) {
   sput_start_testing();
@@ -14,6 +16,13 @@ int main(int argc, char *argv[]) {
   sput_run_test(test_dyn_array_empty);
   sput_run_test(test_dyn_array_nonzero_capacity);
 
+  sput_enter_suite("path");
+  sput_run_test(test_join_path_single_segments);
+  sput_run_test(test_join_path_multiple_segments);
+
+  sput_enter_suite("loader");
+  sput_run_test(test_read_spec_json_missing);
+
   sput_finish_testing();
 
   return sput_get_return_value();

test/specs/minimal_spec_json/run.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+echo "hello world"

test/specs/minimal_spec_json/spec.json

@@ -0,0 +1 @@
+{}

test/specs/no_spec_json/run.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+echo "hello world"

test/test_config.h

@@ -8,6 +8,9 @@ static const char *SAMPLE_CWD = "/home/jrpotter/Documents/bootstrap";
 static const char *SAMPLE_ROOT_DIR = "/usr/local/share/specs";
 static const char *SAMPLE_TARGET = "example-target";
 
+/*
+A valid $CWD environment variable value must be supplied.
+*/
 static void test_config_load_cwd_invalid() {
   struct Config *config = 0;
   enum ConfigError retval =
@@ -15,12 +18,18 @@ static void test_config_load_cwd_invalid() {
   sput_fail_unless(retval == CE_ENV_CWD_INVALID, "target == 0");
 }
 
+/*
+A valid $BOOTSTRAP_ROOT_DIR environment variable value must be supplied.
+*/
 static void test_config_load_root_dir_invalid() {
   struct Config *config = 0;
   enum ConfigError retval = config_load(SAMPLE_CWD, 0, SAMPLE_TARGET, &config);
   sput_fail_unless(retval == CE_ENV_ROOT_DIR_INVALID, "root_dir == 0");
 }
 
+/*
+A valid target value must be supplied.
+*/
 static void test_config_load_target_invalid() {
   struct Config *config = 0;
   enum ConfigError retval =
@@ -28,6 +37,10 @@ static void test_config_load_target_invalid() {
   sput_fail_unless(retval == CE_TARGET_INVALID, "target == 0");
 }
 
+/*
+If the supplied arguments to `config_load` are non-NULL, we should be able to
+successfully construct a new @Config instance.
+*/
 static void test_config_load_success() {
   struct Config *config = 0;
   enum ConfigError retval =

test/test_dyn_array.h

@@ -4,6 +4,9 @@
 #include "dyn_array.h"
 #include "sput.h"
 
+/*
+A @DynArray with zero capacity can be instantiated and have entries pushed onto.
+*/
 static void test_dyn_array_empty() {
   struct DynArray *a = dyn_array_new(0);
   sput_fail_unless(a->size == 0, "a->size == 0");
@@ -22,6 +25,9 @@ static void test_dyn_array_empty() {
   dyn_array_free(a);
 }
 
+/*
+A @DynArray with nonzero capacity can be instantiated and have entries pushed onto.
+*/
 static void test_dyn_array_nonzero_capacity() {
   struct DynArray *a = dyn_array_new(3);
   sput_fail_unless(a->size == 0, "a->size == 0");

test/test_loader.h

@@ -0,0 +1,37 @@
+#ifndef _BOOTSTRAP_TEST_LOADER
+#define _BOOTSTRAP_TEST_LOADER
+
+#include <unistd.h>
+
+#include "cJSON.h"
+#include "config.h"
+#include "loader.h"
+#include "path.h"
+#include "sput.h"
+
+/*
+A missing `spec.json` file is not an error. Our parsed @cJSON instance should
+be set to NULL in this case.
+*/
+static void test_read_spec_json_missing() {
+  char *cwd = getcwd(0, 0);
+
+  const char *segments[] = {cwd, "test", "specs"};
+  char *root_dir = join_path_segments(sizeof(segments) / sizeof(char *), segments);
+
+  struct Config config = {
+    cwd,
+    root_dir,
+    "no_spec_json",
+  };
+
+  cJSON *parsed = 0;
+  enum SpecJsonError retval = read_spec_json(&config, &parsed);
+  sput_fail_unless(retval == 0, "no spec.json, success");
+  sput_fail_unless(parsed == 0, "no spec.json, no parsed");
+
+  free(cwd);
+  free(root_dir);
+}
+
+#endif /* _BOOTSTRAP_TEST_LOADER */

test/test_path.h

@@ -0,0 +1,21 @@
+#ifndef _BOOTSTRAP_TEST_PATH
+#define _BOOTSTRAP_TEST_PATH
+
+#include "path.h"
+#include "sput.h"
+
+static void test_join_path_single_segments() {
+  const char *segments[] = {"abc"};
+  char *joined = join_path_segments(sizeof(segments) / sizeof(char *), segments);
+  sput_fail_unless(strcmp(joined, "abc") == 0, "abc");
+  free(joined);
+}
+
+static void test_join_path_multiple_segments() {
+  const char *segments[] = {"abc", "def", "ghi"};
+  char *joined = join_path_segments(sizeof(segments) / sizeof(char *), segments);
+  sput_fail_unless(strcmp(joined, "abc/def/ghi") == 0, "abc/def/ghi");
+  free(joined);
+}
+
+#endif /* _BOOTSTRAP_TEST_PATH */