Add error_response

Start adding connection abstraction

1 files changed, 170 insertions, 0 deletions

diff --git a/src/error_response.zig b/src/error_response.zig
new file mode 100644
index 0000000..4d99ba4
--- /dev/null
+++ b/src/error_response.zig
@@ -0,0 +1,170 @@
+const std = @import("std");
+const HMByteString = std.AutoHashMap(u8, []const u8);
+const ByteArrayList = std.ArrayList(u8);
+const ProtocolError = @import("main.zig").ProtocolError;
+
+const ErrorResponse = @This();
+const Tag: u8 = 'E';
+
+buf: ?[]const u8 = null, // owned
+severity: []const u8,
+severity_unlocalized: ?[]const u8 = null,
+code: []const u8,
+message: []const u8,
+detail: ?[]const u8 = null,
+hint: ?[]const u8 = null,
+position: ?u32 = null,
+internal_position: ?u32 = null,
+internal_query: ?[]const u8 = null,
+where: ?[]const u8 = null,
+schema_name: ?[]const u8 = null,
+table_name: ?[]const u8 = null,
+column_name: ?[]const u8 = null,
+data_type_name: ?[]const u8 = null,
+constraint_name: ?[]const u8 = null,
+file_name: ?[]const u8 = null,
+line: ?u32 = null,
+routine: ?[]const u8 = null,
+unknown_fields: HMByteString,
+
+pub fn read(allocator: std.mem.Allocator, b: []const u8) !ErrorResponse {
+    var res: ErrorResponse = undefined;
+    res.unknown_fields = HMByteString.init(allocator);
+    res.buf = try allocator.dupe(u8, b);
+    errdefer allocator.free(res.buf.?);
+    var it = std.mem.splitScalar(u8, res.buf.?, 0);
+    var setSev = false; var setCode = false; var setMsg = false;
+    while (it.next()) |next| {
+        if (next.len < 1) break;
+        switch (next[0]) {
+            0 => break,
+            'S' => {
+                res.severity = next[1..];
+                setSev = true;
+            },
+            'V' => {
+                res.severity_unlocalized = next[1..];
+            },
+            'C' => {
+                res.code = next[1..];
+                setCode = true;
+            },
+            'M' => {
+                res.message = next[1..];
+                setMsg = true;
+            },
+            'D' => {
+                res.detail = next[1..];
+            },
+            'H' => {
+                res.hint = next[1..];
+            },
+            'P' => {
+                res.position = try std.fmt.parseInt(u32, next[1..], 10);
+            },
+            'p' => {
+                res.internal_position = try std.fmt.parseInt(u32, next[1..], 10);
+            },
+            'q' => {
+                res.internal_query = next[1..];
+            },
+            'W' => {
+                res.where = next[1..];
+            },
+            's' => {
+                res.schema_name = next[1..];
+            },
+            't' => {
+                res.table_name = next[1..];
+            },
+            'c' => {
+                res.column_name = next[1..];
+            },
+            'd' => {
+                res.data_type_name = next[1..];
+            },
+            'n' => {
+                res.constraint_name = next[1..];
+            },
+            'F' => {
+                res.file_name = next[1..];
+            },
+            'L' => {
+                res.line = try std.fmt.parseInt(u32, next[1..], 10);
+            },
+            'R' => {
+                res.routine = next[1..];
+            },
+            else => {
+                try res.unknown_fields.put(next[0], next[1..]);
+            }
+        }
+    }
+    if (!(setSev and setCode and setMsg)) return ProtocolError.MissingField;
+    return res;
+}
+pub fn write(self: ErrorResponse, allocator: std.mem.Allocator, stream_writer: anytype) !void {
+    try stream_writer.writeByte(Tag);
+    var al = ByteArrayList.init(allocator);
+    defer al.deinit();
+    var cw = std.io.countingWriter(al.writer());
+    var writer = cw.writer();
+    try writer.writeIntBig(u32, 0); // Length placeholder.
+
+    try write_field_nt('S', self, "severity", writer);
+    if (self.severity_unlocalized) |severity_unlocalized| {
+        try write_nt('V', severity_unlocalized, writer);
+    }
+    try write_field_nt('C', self, "code", writer);
+    try write_field_nt('M', self, "message", writer);
+    // TODO rest of the fields
+
+    // replace the length and write it to the actual stream
+    std.mem.writeIntBig(u32, al.items[0..4], @as(u32, @intCast(cw.bytes_written)));
+    try stream_writer.writeAll(al.items);
+}
+fn write_field_nt(comptime tag: u8, self: ErrorResponse, comptime field: []const u8, writer: anytype) !void {
+    try write_nt(tag, @field(self, field), writer);
+}
+fn write_nt(comptime tag: u8, value: []const u8, writer: anytype) !void {
+    try writer.writeByte(tag);
+    try writer.writeAll(value);
+    try writer.writeByte(0);
+}
+
+pub fn deinit(self: *ErrorResponse, allocator: std.mem.Allocator) void {
+    self.unknown_fields.deinit();
+    if (self.buf != null) allocator.free(self.buf.?);
+}
+
+test "round trip" {
+    const allocator = std.testing.allocator;
+    var sm = ErrorResponse{
+        .severity = "foo",
+        .severity_unlocalized = "foo_unlocal",
+        .code = "bar",
+        .message = "baz",
+        .unknown_fields = HMByteString.init(allocator),
+    };
+    defer sm.deinit(allocator);
+
+    var bal = ByteArrayList.init(allocator);
+    defer bal.deinit();
+    try sm.write(allocator, bal.writer());
+
+    var fbs = std.io.fixedBufferStream(bal.items);
+    var reader = fbs.reader();
+    const tag = try reader.readByte();
+    try std.testing.expectEqual(Tag, tag);
+    const len = try reader.readIntBig(u32);
+    const buf = try allocator.alloc(u8, len - 4);
+    defer allocator.free(buf);
+    try reader.readNoEof(buf);
+    var sm2 = try ErrorResponse.read(allocator, buf);
+    defer sm2.deinit(allocator);
+
+    try std.testing.expectEqualStrings("foo", sm2.severity);
+    try std.testing.expectEqualStrings("foo_unlocal", sm2.severity_unlocalized.?);
+    try std.testing.expectEqualStrings("bar", sm2.code);
+    try std.testing.expectEqualStrings("baz", sm2.message);
+}