config: add parsing and getter for paths

CHANGELOG.md

@@ -7,6 +7,10 @@ v0.22 + 1
 
 ### API additions
 
+* Parsing and retrieving a configuration value as a path is exposed
+  via `git_config_parse_path()` and `git_config_get_path()`
+  respectively.
+
 ### API removals
 
 ### Breaking API changes

include/git2/config.h

@@ -320,6 +320,24 @@ GIT_EXTERN(int) git_config_get_int64(int64_t *out, const git_config *cfg, const
 GIT_EXTERN(int) git_config_get_bool(int *out, const git_config *cfg, const char *name);
 
 /**
+ * Get the value of a path config variable.
+ *
+ * A leading '~' will be expanded to the global search path (which
+ * defaults to the user's home directory but can be overridden via
+ * `git_libgit2_opts()`.
+ *
+ * All config files will be looked into, in the order of their
+ * defined level. A higher level means a higher priority. The
+ * first occurrence of the variable will be returned here.
+ *
+ * @param out the buffer in which to store the result
+ * @param cfg where to look for the variable
+ * @param name the variable's name
+ * @param 0 or an error code
+ */
+GIT_EXTERN(int) git_config_get_path(git_buf *out, const git_config *cfg, const char *name);
+
+/**
  * Get the value of a string config variable.
  *
  * The string is owned by the variable and should not be freed by the
@@ -615,6 +633,20 @@ GIT_EXTERN(int) git_config_parse_int32(int32_t *out, const char *value);
  */
 GIT_EXTERN(int) git_config_parse_int64(int64_t *out, const char *value);
 
+/**
+ * Parse a string value as a path.
+ *
+ * A leading '~' will be expanded to the global search path (which
+ * defaults to the user's home directory but can be overridden via
+ * `git_libgit2_opts()`.
+ *
+ * If the value does not begin with a tilde, the input will be
+ * returned.
+ *
+ * @param out placae to store the result of parsing
+ * @param value the path to evaluate
+ */
+GIT_EXTERN(int) git_config_parse_path(git_buf *out, const char *value);
 
 /**
  * Perform an operation on each config variable in given config backend

src/config.c

@@ -785,6 +785,17 @@ int git_config_get_bool(int *out, const git_config *cfg, const char *name)
 	return git_config_parse_bool(out, entry->value);
 }
 
+int git_config_get_path(git_buf *out, const git_config *cfg, const char *name)
+{
+	const git_config_entry *entry;
+	int error;
+
+	if ((error = get_entry(&entry, cfg, name, true, GET_ALL_ERRORS)) < 0)
+		return error;
+
+	return git_config_parse_path(out, entry->value);
+}
+
 int git_config_get_string(
 	const char **out, const git_config *cfg, const char *name)
 {
@@ -1184,6 +1195,36 @@ fail_parse:
 	return -1;
 }
 
+int git_config_parse_path(git_buf *out, const char *value)
+{
+	int error = 0;
+	const git_buf *home;
+
+	assert(out && value);
+
+	git_buf_sanitize(out);
+
+	if (value[0] == '~') {
+		if (value[1] != '\0' && value[1] != '/') {
+			giterr_set(GITERR_CONFIG, "retrieving a homedir by name is not supported");
+			return -1;
+		}
+
+		if ((error = git_sysdir_get(&home, GIT_SYSDIR_GLOBAL)) < 0)
+			return error;
+
+		git_buf_sets(out, home->ptr);
+		git_buf_puts(out, value + 1);
+
+		if (git_buf_oom(out))
+			return -1;
+
+		return 0;
+	}
+
+	return git_buf_sets(out, value);
+}
+
 /* Take something the user gave us and make it nice for our hash function */
 int git_config__normalize_name(const char *in, char **out)
 {

tests/config/read.c

 #include "clar_libgit2.h"
+#include "buffer.h"
+#include "path.h"
 
 void test_config_read__simple_read(void)
 {
@@ -567,3 +569,47 @@ void test_config_read__override_variable(void)
 
 	git_config_free(cfg);
 }
+
+void test_config_read__path(void)
+{
+	git_config *cfg;
+	git_buf path = GIT_BUF_INIT;
+	git_buf old_path = GIT_BUF_INIT;
+	git_buf home_path = GIT_BUF_INIT;
+	git_buf expected_path = GIT_BUF_INIT;
+
+	cl_git_pass(p_mkdir("fakehome", 0777));
+	cl_git_pass(git_path_prettify(&home_path, "fakehome", NULL));
+	cl_git_pass(git_libgit2_opts(GIT_OPT_GET_SEARCH_PATH, GIT_CONFIG_LEVEL_GLOBAL, &old_path));
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_SEARCH_PATH, GIT_CONFIG_LEVEL_GLOBAL, home_path.ptr));
+	cl_git_mkfile("./testconfig", "[some]\n path = ~/somefile");
+	cl_git_pass(git_path_join_unrooted(&expected_path, "somefile", home_path.ptr, NULL));
+
+	cl_git_pass(git_config_open_ondisk(&cfg, "./testconfig"));
+	cl_git_pass(git_config_get_path(&path, cfg, "some.path"));
+	cl_assert_equal_s(expected_path.ptr, path.ptr);
+	git_buf_free(&path);
+
+	cl_git_mkfile("./testconfig", "[some]\n path = ~/");
+	cl_git_pass(git_path_join_unrooted(&expected_path, "", home_path.ptr, NULL));
+
+	cl_git_pass(git_config_get_path(&path, cfg, "some.path"));
+	cl_assert_equal_s(expected_path.ptr, path.ptr);
+	git_buf_free(&path);
+
+	cl_git_mkfile("./testconfig", "[some]\n path = ~");
+	cl_git_pass(git_buf_sets(&expected_path, home_path.ptr));
+
+	cl_git_pass(git_config_get_path(&path, cfg, "some.path"));
+	cl_assert_equal_s(expected_path.ptr, path.ptr);
+	git_buf_free(&path);
+
+	cl_git_mkfile("./testconfig", "[some]\n path = ~user/foo");
+	cl_git_fail(git_config_get_path(&path, cfg, "some.path"));
+
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_SEARCH_PATH, GIT_CONFIG_LEVEL_GLOBAL, old_path.ptr));
+	git_buf_free(&old_path);
+	git_buf_free(&home_path);
+	git_buf_free(&expected_path);
+	git_config_free(cfg);
+}