thodg/libgit2

diff --git a/include/git2/errors.h b/include/git2/errors.h
index 7daa067..bc420d1 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -126,6 +126,7 @@ typedef enum {
 	GITERR_REFERENCE,
 	GITERR_ZLIB,
 	GITERR_REPOSITORY,
+	GITERR_CONFIG,
 } git_error_class;
 
 #define GITERR_CHECK_ALLOC(ptr) if (ptr == NULL) { return -1; }
diff --git a/src/config.c b/src/config.c
index 9122241..850c9b1 100644
--- a/src/config.c
+++ b/src/config.c
@@ -67,77 +67,71 @@ int git_config_new(git_config **out)
 
 	if (git_vector_init(&cfg->files, 3, config_backend_cmp) < 0) {
 		git__free(cfg);
-		return GIT_ENOMEM;
+		return -1;
 	}
 
 	*out = cfg;
 	GIT_REFCOUNT_INC(cfg);
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_config_add_file_ondisk(git_config *cfg, const char *path, int priority)
 {
 	git_config_file *file = NULL;
-	int error;
 
-	error = git_config_file__ondisk(&file, path);
-	if (error < GIT_SUCCESS)
-		return error;
+	if (git_config_file__ondisk(&file, path) < 0)
+		return -1;
 
-	error = git_config_add_file(cfg, file, priority);
-	if (error < GIT_SUCCESS) {
+	if (git_config_add_file(cfg, file, priority) < 0) {
 		/*
 		 * free manually; the file is not owned by the config
 		 * instance yet and will not be freed on cleanup
 		 */
 		file->free(file);
-		return error;
+		return -1;
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_config_open_ondisk(git_config **cfg, const char *path)
 {
-	int error;
-
-	error = git_config_new(cfg);
-	if (error < GIT_SUCCESS)
-		return error;
+	if (git_config_new(cfg) < 0)
+		return -1;
 
-	error = git_config_add_file_ondisk(*cfg, path, 1);
-	if (error < GIT_SUCCESS)
+	if (git_config_add_file_ondisk(*cfg, path, 1) < 0) {
 		git_config_free(*cfg);
+		return -1;
+	}
 
-	return error;
+	return 0;
 }
 
 int git_config_add_file(git_config *cfg, git_config_file *file, int priority)
 {
 	file_internal *internal;
-	int error;
+	int result;
 
 	assert(cfg && file);
 
-	if ((error = file->open(file)) < GIT_SUCCESS)
-		return git__throw(error, "Failed to open config file");
+	if ((result = file->open(file)) < 0)
+		return result;
 
 	internal = git__malloc(sizeof(file_internal));
-	if (internal == NULL)
-		return GIT_ENOMEM;
+	GITERR_CHECK_ALLOC(internal);
 
 	internal->file = file;
 	internal->priority = priority;
 
 	if (git_vector_insert(&cfg->files, internal) < 0) {
 		git__free(internal);
-		return GIT_ENOMEM;
+		return -1;
 	}
 
 	git_vector_sort(&cfg->files);
 	internal->file->cfg = cfg;
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 /*
@@ -165,8 +159,7 @@ int git_config_delete(git_config *cfg, const char *name)
 	file_internal *internal;
 	git_config_file *file;
 
-	if (cfg->files.length == 0)
-		return git__throw(GIT_EINVALIDARGS, "Cannot delete variable; no files open in the `git_config` instance");
+	assert(cfg->files.length);
 
 	internal = git_vector_get(&cfg->files, 0);
 	file = internal->file;
@@ -200,8 +193,7 @@ int git_config_set_string(git_config *cfg, const char *name, const char *value)
 	file_internal *internal;
 	git_config_file *file;
 
-	if (cfg->files.length == 0)
-		return git__throw(GIT_EINVALIDARGS, "Cannot set variable value; no files open in the `git_config` instance");
+	assert(cfg->files.length);
 
 	internal = git_vector_get(&cfg->files, 0);
 	file = internal->file;
@@ -239,7 +231,7 @@ static int parse_int64(int64_t *out, const char *value)
 	int64_t num;
 
 	if (git__strtol64(&num, value, &num_end, 0) < 0)
-		return GIT_EINVALIDTYPE;
+		return -1;
 
 	switch (*num_end) {
 	case 'g':
@@ -259,7 +251,7 @@ static int parse_int64(int64_t *out, const char *value)
 		/* check that that there are no more characters after the
 		 * given modifier suffix */
 		if (num_end[1] != '\0')
-			return GIT_EINVALIDTYPE;
+			return -1;
 
 		/* fallthrough */
 
@@ -268,7 +260,7 @@ static int parse_int64(int64_t *out, const char *value)
 		return 0;
 
 	default:
-		return GIT_EINVALIDTYPE;
+		return -1;
 	}
 }
 
@@ -278,11 +270,11 @@ static int parse_int32(int32_t *out, const char *value)
 	int32_t truncate;
 
 	if (parse_int64(&tmp, value) < 0)
-		return GIT_EINVALIDTYPE;
+		return -1;
 
 	truncate = tmp & 0xFFFFFFFF;
 	if (truncate != tmp)
-		return GIT_EOVERFLOW;
+		return -1;
 
 	*out = truncate;
 	return 0;
@@ -332,8 +324,9 @@ int git_config_get_mapped(git_config *cfg, const char *name, git_cvar_map *maps,
 		}
 	}
 
-	return git__throw(GIT_ENOTFOUND,
+	giterr_set(GITERR_CONFIG,
 		"Failed to map the '%s' config variable with a valid value", name);
+	return -1;
 }
 
 int git_config_get_int64(git_config *cfg, const char *name, int64_t *out)
@@ -342,69 +335,80 @@ int git_config_get_int64(git_config *cfg, const char *name, int64_t *out)
 	int ret;
 
 	ret = git_config_get_string(cfg, name, &value);
-	if (ret < GIT_SUCCESS)
-		return git__rethrow(ret, "Failed to retrieve value for '%s'", name);
+	if (ret < 0)
+		return ret;
 
-	if (parse_int64(out, value) < 0)
-		return git__throw(GIT_EINVALIDTYPE, "Failed to parse '%s' as an integer", value);
+	if (parse_int64(out, value) < 0) {
+		giterr_set(GITERR_CONFIG, "Failed to parse '%s' as an integer", value);
+		return -1;
+	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_config_get_int32(git_config *cfg, const char *name, int32_t *out)
 {
 	const char *value;
-	int error;
+	int ret;
 
-	error = git_config_get_string(cfg, name, &value);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to get value for %s", name);
+	ret = git_config_get_string(cfg, name, &value);
+	if (ret < 0)
+		return ret;
 
-	error = parse_int32(out, value);
-	if (error < GIT_SUCCESS)
-		return git__throw(GIT_EINVALIDTYPE, "Failed to parse '%s' as a 32-bit integer", value);
+	if (parse_int32(out, value) < 0) {
+		giterr_set(GITERR_CONFIG, "Failed to parse '%s' as a 32-bit integer", value);
+		return -1;
+	}
 	
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_config_get_bool(git_config *cfg, const char *name, int *out)
 {
 	const char *value;
-	int error = GIT_SUCCESS;
+	int ret;
 
-	error = git_config_get_string(cfg, name, &value);
-	if (error < GIT_SUCCESS)
-		return git__rethrow(error, "Failed to get value for %s", name);
+	ret = git_config_get_string(cfg, name, &value);
+	if (ret < 0)
+		return ret;
 
 	if (parse_bool(out, value) == 0)
-		return GIT_SUCCESS;
+		return 0;
 
 	if (parse_int32(out, value) == 0) {
 		*out = !!(*out);
-		return GIT_SUCCESS;
+		return 0;
 	}
 
-	return git__throw(GIT_EINVALIDTYPE, "Failed to parse '%s' as a boolean value", value);
+	giterr_set(GITERR_CONFIG, "Failed to parse '%s' as a boolean value", value);
+	return -1;
 }
 
 int git_config_get_string(git_config *cfg, const char *name, const char **out)
 {
 	file_internal *internal;
 	git_config_file *file;
-	int error = GIT_ENOTFOUND;
+	int ret = GIT_ENOTFOUND;
 	unsigned int i;
 
-	if (cfg->files.length == 0)
-		return git__throw(GIT_EINVALIDARGS, "Cannot get variable value; no files open in the `git_config` instance");
+	assert(cfg->files.length);
 
 	for (i = 0; i < cfg->files.length; ++i) {
 		internal = git_vector_get(&cfg->files, i);
 		file = internal->file;
-		if ((error = file->get(file, name, out)) == GIT_SUCCESS)
-			return GIT_SUCCESS;
+
+		ret = file->get(file, name, out);
+		if (ret == 0)
+			return 0;
+
+		if (ret == GIT_ENOTFOUND)
+			continue;
+
+		return ret;
 	}
 
-	return git__throw(error, "Config value '%s' not found", name);
+	giterr_set(GITERR_CONFIG, "Config value '%s' not found", name);
+	return GIT_ENOTFOUND;
 }
 
 int git_config_get_multivar(git_config *cfg, const char *name, const char *regexp,
@@ -412,12 +416,10 @@ int git_config_get_multivar(git_config *cfg, const char *name, const char *regex
 {
 	file_internal *internal;
 	git_config_file *file;
-	int error = GIT_ENOTFOUND;
+	int ret = GIT_ENOTFOUND;
 	unsigned int i;
 
-
-	if (cfg->files.length == 0)
-		return git__throw(GIT_EINVALIDARGS, "Cannot get variable value; no files open in the `git_config` instance");
+	assert(cfg->files.length);
 
 	/*
 	 * This loop runs the "wrong" way 'round because we need to
@@ -426,30 +428,30 @@ int git_config_get_multivar(git_config *cfg, const char *name, const char *regex
 	for (i = cfg->files.length; i > 0; --i) {
 		internal = git_vector_get(&cfg->files, i - 1);
 		file = internal->file;
-		error = file->get_multivar(file, name, regexp, fn, data);
-		if (error < GIT_SUCCESS && error != GIT_ENOTFOUND)
-			git__rethrow(error, "Failed to get multivar");
+		ret = file->get_multivar(file, name, regexp, fn, data);
+		if (ret < 0 && ret != GIT_ENOTFOUND)
+			return ret;
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_config_set_multivar(git_config *cfg, const char *name, const char *regexp, const char *value)
 {
 	file_internal *internal;
 	git_config_file *file;
-	int error = GIT_ENOTFOUND;
+	int ret = GIT_ENOTFOUND;
 	unsigned int i;
 
 	for (i = cfg->files.length; i > 0; --i) {
 		internal = git_vector_get(&cfg->files, i - 1);
 		file = internal->file;
-		error = file->set_multivar(file, name, regexp, value);
-		if (error < GIT_SUCCESS && error != GIT_ENOTFOUND)
-			git__rethrow(error, "Failed to replace multivar");
+		ret = file->set_multivar(file, name, regexp, value);
+		if (ret < GIT_SUCCESS && ret != GIT_ENOTFOUND)
+			return ret;
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 int git_config_find_global_r(git_buf *path)
@@ -460,18 +462,23 @@ int git_config_find_global_r(git_buf *path)
 int git_config_find_global(char *global_config_path)
 {
 	git_buf path  = GIT_BUF_INIT;
-	int     error = git_config_find_global_r(&path);
+	int     ret = git_config_find_global_r(&path);
 
-	if (error == GIT_SUCCESS) {
-		if (path.size > GIT_PATH_MAX)
-			error = git__throw(GIT_ESHORTBUFFER, "Path is too long");
-		else
-			git_buf_copy_cstr(global_config_path, GIT_PATH_MAX, &path);
+	if (ret < 0) {
+		git_buf_free(&path);
+		return ret;
 	}
 
-	git_buf_free(&path);
+	if (path.size > GIT_PATH_MAX) {
+		git_buf_free(&path);
+		giterr_set(GITERR_NOMEMORY,
+			"Path is to long to fit on the given buffer");
+		return -1;
+	}
 
-	return error;
+	git_buf_copy_cstr(global_config_path, GIT_PATH_MAX, &path);
+	git_buf_free(&path);
+	return 0;
 }
 
 int git_config_find_system_r(git_buf *path)
@@ -482,18 +489,23 @@ int git_config_find_system_r(git_buf *path)
 int git_config_find_system(char *system_config_path)
 {
 	git_buf path  = GIT_BUF_INIT;
-	int     error = git_config_find_system_r(&path);
+	int     ret = git_config_find_system_r(&path);
 
-	if (error == GIT_SUCCESS) {
-		if (path.size > GIT_PATH_MAX)
-			error = git__throw(GIT_ESHORTBUFFER, "Path is too long");
-		else
-			git_buf_copy_cstr(system_config_path, GIT_PATH_MAX, &path);
+	if (ret < 0) {
+		git_buf_free(&path);
+		return ret;
 	}
 
-	git_buf_free(&path);
+	if (path.size > GIT_PATH_MAX) {
+		git_buf_free(&path);
+		giterr_set(GITERR_NOMEMORY,
+			"Path is to long to fit on the given buffer");
+		return -1;
+	}
 
-	return error;
+	git_buf_copy_cstr(system_config_path, GIT_PATH_MAX, &path);
+	git_buf_free(&path);
+	return 0;
 }
 
 int git_config_open_global(git_config **out)
@@ -501,7 +513,7 @@ int git_config_open_global(git_config **out)
 	int error;
 	char global_path[GIT_PATH_MAX];
 
-	if ((error = git_config_find_global(global_path)) < GIT_SUCCESS)
+	if ((error = git_config_find_global(global_path)) < 0)
 		return error;
 
 	return git_config_open_ondisk(out, global_path);
diff --git a/src/fileops.c b/src/fileops.c
index 4414c86..c6a3be7 100644
--- a/src/fileops.c
+++ b/src/fileops.c
@@ -295,7 +295,6 @@ int git_futils_rmdir_r(const char *path, int force)
 
 int git_futils_find_global_file(git_buf *path, const char *filename)
 {
-	int error;
 	const char *home = getenv("HOME");
 
 #ifdef GIT_WIN32
@@ -303,19 +302,21 @@ int git_futils_find_global_file(git_buf *path, const char *filename)
 		home = getenv("USERPROFILE");
 #endif
 
-	if (home == NULL)
-		return git__throw(GIT_EOSERR, "Failed to open global %s file. "
-			"Cannot locate the user's home directory.", filename);
+	if (home == NULL) {
+		giterr_set(GITERR_OS, "Global file lookup failed. "
+			"Cannot locate the user's home directory");
+		return -1;
+	}
 
-	if ((error = git_buf_joinpath(path, home, filename)) < GIT_SUCCESS)
-		return error;
+	if (git_buf_joinpath(path, home, filename) < 0)
+		return -1;
 
 	if (git_path_exists(path->ptr) == false) {
 		git_buf_clear(path);
 		return GIT_ENOTFOUND;
 	}
 
-	return GIT_SUCCESS;
+	return 0;
 }
 
 #ifdef GIT_WIN32