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authorGravatar Adam Chlipala <adamc@hcoop.net>2008-07-29 15:25:42 -0400
committerGravatar Adam Chlipala <adamc@hcoop.net>2008-07-29 15:25:42 -0400
commitcb3b3831a07d6674a5fa02e3e8a1e4329b58cb34 (patch)
tree7b6064344549091735d28d42ac9fb19073e9760a
parent6855e4766fa8d07e2f3e3cd468de6c58fed0c903 (diff)
Unurlifying a datatype; longjmp-based error signaling mechanism
Diffstat
-rw-r--r--include/lacweb.h7
-rw-r--r--include/types.h3
-rw-r--r--src/c/driver.c62
-rw-r--r--src/c/lacweb.c51
-rw-r--r--src/cjr_print.sml38
-rw-r--r--src/monoize.sml2
6 files changed, 142 insertions, 21 deletions
diff --git a/include/lacweb.h b/include/lacweb.h
index 09f002fd..13db1f7b 100644
--- a/include/lacweb.h
+++ b/include/lacweb.h
@@ -9,6 +9,13 @@ extern lw_unit lw_unit_v;
lw_context lw_init(size_t page_len, size_t heap_len);
void lw_free(lw_context);
void lw_reset(lw_context);
+void lw_reset_keep_request(lw_context);
+void lw_reset_keep_error_message(lw_context);
+failure_kind lw_begin(lw_context, char *path);
+
+void lw_error(lw_context, failure_kind, const char *fmt, ...);
+char *lw_error_message(lw_context);
+
void *lw_malloc(lw_context, size_t);
int lw_send(lw_context, int sock);
diff --git a/include/types.h b/include/types.h
index 81cec229..169952cb 100644
--- a/include/types.h
+++ b/include/types.h
@@ -12,3 +12,6 @@ typedef struct lw_context *lw_context;
typedef lw_Basis_string lw_Basis_xhtml;
typedef lw_Basis_string lw_Basis_page;
+
+
+typedef enum { SUCCESS, FATAL, BOUNDED_RETRY, UNLIMITED_RETRY } failure_kind;
diff --git a/src/c/driver.c b/src/c/driver.c
index 90538104..21001d0c 100644
--- a/src/c/driver.c
+++ b/src/c/driver.c
@@ -13,8 +13,6 @@ int lw_port = 8080;
int lw_backlog = 10;
int lw_bufsize = 1024;
-void lw_handle(lw_context, char*);
-
typedef struct node {
int fd;
struct node *next;
@@ -51,6 +49,8 @@ static int dequeue() {
static pthread_mutex_t queue_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t queue_cond = PTHREAD_COND_INITIALIZER;
+#define MAX_RETRIES 5
+
static void *worker(void *data) {
int me = *(int *)data;
lw_context ctx = lw_init(1024, 1024);
@@ -68,6 +68,7 @@ static void *worker(void *data) {
printf("Handling connection with thread #%d.\n", me);
while (1) {
+ unsigned retries_left = MAX_RETRIES;
int r = recv(sock, back, lw_bufsize - (back - buf), 0);
if (r < 0) {
@@ -138,11 +139,58 @@ static void *worker(void *data) {
printf("Serving URI %s....\n", path);
- lw_write (ctx, "HTTP/1.1 200 OK\r\n");
- lw_write(ctx, "Content-type: text/html\r\n\r\n");
- lw_write(ctx, "<html>");
- lw_handle(ctx, path);
- lw_write(ctx, "</html>");
+ while (1) {
+ failure_kind fk;
+
+ lw_write(ctx, "HTTP/1.1 200 OK\r\n");
+ lw_write(ctx, "Content-type: text/html\r\n\r\n");
+ lw_write(ctx, "<html>");
+
+ fk = lw_begin(ctx, path);
+ if (fk == SUCCESS) {
+ lw_write(ctx, "</html>");
+ break;
+ } else if (fk == BOUNDED_RETRY) {
+ if (retries_left) {
+ printf("Error triggers bounded retry: %s\n", lw_error_message(ctx));
+ --retries_left;
+ }
+ else {
+ printf("Fatal error (out of retries): %s\n", lw_error_message(ctx));
+
+ lw_reset_keep_error_message(ctx);
+ lw_write(ctx, "HTTP/1.1 500 Internal Server Error\n\r");
+ lw_write(ctx, "Content-type: text/plain\r\n\r\n");
+ lw_write(ctx, "Fatal error (out of retries): ");
+ lw_write(ctx, lw_error_message(ctx));
+ lw_write(ctx, "\n");
+ }
+ } else if (fk == UNLIMITED_RETRY)
+ printf("Error triggers unlimited retry: %s\n", lw_error_message(ctx));
+ else if (fk == FATAL) {
+ printf("Fatal error: %s\n", lw_error_message(ctx));
+
+ lw_reset_keep_error_message(ctx);
+ lw_write(ctx, "HTTP/1.1 500 Internal Server Error\n\r");
+ lw_write(ctx, "Content-type: text/plain\r\n\r\n");
+ lw_write(ctx, "Fatal error: ");
+ lw_write(ctx, lw_error_message(ctx));
+ lw_write(ctx, "\n");
+
+ break;
+ } else {
+ printf("Unknown lw_handle return code!\n");
+
+ lw_reset_keep_request(ctx);
+ lw_write(ctx, "HTTP/1.1 500 Internal Server Error\n\r");
+ lw_write(ctx, "Content-type: text/plain\r\n\r\n");
+ lw_write(ctx, "Unknown lw_handle return code!\n");
+
+ break;
+ }
+
+ lw_reset_keep_request(ctx);
+ }
lw_send(ctx, sock);
diff --git a/src/c/lacweb.c b/src/c/lacweb.c
index 9543c642..523071fd 100644
--- a/src/c/lacweb.c
+++ b/src/c/lacweb.c
@@ -3,15 +3,24 @@
#include <string.h>
#include <ctype.h>
#include <assert.h>
+#include <setjmp.h>
+#include <stdarg.h>
#include "types.h"
lw_unit lw_unit_v = {};
+#define ERROR_BUF_LEN 1024
+
struct lw_context {
char *page, *page_front, *page_back;
char *heap, *heap_front, *heap_back;
char **inputs;
+
+ jmp_buf jmp_buf;
+
+ failure_kind failure_kind;
+ char error_message[ERROR_BUF_LEN];
};
extern int lw_inputs_len;
@@ -27,6 +36,9 @@ lw_context lw_init(size_t page_len, size_t heap_len) {
ctx->inputs = calloc(lw_inputs_len, sizeof(char *));
+ ctx->failure_kind = SUCCESS;
+ ctx->error_message[0] = 0;
+
return ctx;
}
@@ -37,12 +49,49 @@ void lw_free(lw_context ctx) {
free(ctx);
}
-void lw_reset(lw_context ctx) {
+void lw_reset_keep_request(lw_context ctx) {
+ ctx->page_front = ctx->page;
+ ctx->heap_front = ctx->heap;
+
+ ctx->failure_kind = SUCCESS;
+ ctx->error_message[0] = 0;
+}
+
+void lw_reset_keep_error_message(lw_context ctx) {
ctx->page_front = ctx->page;
ctx->heap_front = ctx->heap;
+
+ ctx->failure_kind = SUCCESS;
+}
+
+void lw_reset(lw_context ctx) {
+ lw_reset_keep_request(ctx);
memset(ctx->inputs, 0, lw_inputs_len * sizeof(char *));
}
+void lw_handle(lw_context, char *);
+
+failure_kind lw_begin(lw_context ctx, char *path) {
+ if (!setjmp(ctx->jmp_buf))
+ lw_handle(ctx, path);
+
+ return ctx->failure_kind;
+}
+
+void lw_error(lw_context ctx, failure_kind fk, const char *fmt, ...) {
+ va_list ap;
+ va_start(ap, fmt);
+
+ ctx->failure_kind = fk;
+ vsnprintf(ctx->error_message, ERROR_BUF_LEN, fmt, ap);
+
+ longjmp(ctx->jmp_buf, 1);
+}
+
+char *lw_error_message(lw_context ctx) {
+ return ctx->error_message;
+}
+
int lw_input_num(char*);
void lw_set_input(lw_context ctx, char *name, char *value) {
diff --git a/src/cjr_print.sml b/src/cjr_print.sml
index 1aab8f02..ab102800 100644
--- a/src/cjr_print.sml
+++ b/src/cjr_print.sml
@@ -211,7 +211,7 @@ fun p_decl env (dAll as (d, _) : decl) =
newline,
string "struct",
space,
- string ("_lwd_" ^ x ^ "_" ^ Int.toString n),
+ string ("__lwd_" ^ x ^ "_" ^ Int.toString n),
space,
string "{",
newline,
@@ -451,34 +451,48 @@ fun p_file env (ds, ps) =
fun doEm xncs =
case xncs of
- [] => string "Uh oh"
- | (x, n, to) :: rest =>
- box [string "(!strcmp(request, \"",
- string x,
- string "\") ? ({",
+ [] => string ("(lw_error(ctx, FATAL, \"Error unurlifying datatype " ^ x ^ "\"), NULL)")
+ | (x', n, to) :: rest =>
+ box [string "((!strncmp(request, \"",
+ string x',
+ string "\", ",
+ string (Int.toString (size x')),
+ string ") && (request[",
+ string (Int.toString (size x')),
+ string "] == 0 || request[",
+ string (Int.toString (size x')),
+ string "] == '/')) ? ({",
newline,
+ string "struct",
+ space,
string ("__lwd_" ^ x ^ "_" ^ Int.toString i),
space,
- string "__lw_tmp;",
+ string "*__lw_tmp = lw_malloc(ctx, sizeof(struct __lwd_",
+ string x,
+ string "_",
+ string (Int.toString i),
+ string "));",
newline,
- string "__lw_tmp.tag",
+ string "__lw_tmp->tag",
space,
string "=",
space,
- string ("__lwc_" ^ x ^ "_" ^ Int.toString n),
+ string ("__lwc_" ^ x' ^ "_" ^ Int.toString n),
string ";",
newline,
string "request",
space,
string "+=",
space,
- string (Int.toString (size x)),
+ string (Int.toString (size x')),
string ";",
newline,
+ string "if (request[0] == '/') ++request;",
+ newline,
case to of
NONE => box []
- | SOME t => box [string "__lw_tmp.data.",
- string x,
+ | SOME t => box [string "__lw_tmp->data.",
+ string x',
space,
string "=",
space,
diff --git a/src/monoize.sml b/src/monoize.sml
index 8e3bfaba..e45597b2 100644
--- a/src/monoize.sml
+++ b/src/monoize.sml
@@ -115,7 +115,7 @@ fun fooifyExp name env =
| L'.TFfi ("Basis", "float") => (L'.EFfiApp ("Basis", name ^ "ifyFloat", [e]), loc)
| L'.TRecord [] => (L'.EPrim (Prim.String ""), loc)
- | L'.TNamed _ => (L'.EPrim (Prim.String ""), loc)
+ | L'.TNamed _ => (L'.EPrim (Prim.String "A"), loc)
| _ => (E.errorAt loc "Don't know how to encode attribute type";
Print.eprefaces' [("Type", MonoPrint.p_typ MonoEnv.empty tAll)];
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