wip getting closer

src/passbook.c

@@ -5,13 +5,19 @@
 
 #include "debug.h"
 
+/**
+  The idea is to eventually implement state dumping by writing a series
+  of commands to a file <file> that we can then reload next time by doing
+  cat <file> - | ./passbook
+**/
+
 const char INSTRUCTION_PUT[] = "put";
 
-const char INSTRUCTION_REMOVE[] = "rem";
+const char INSTRUCTION_REM[] = "rem";
 
 const char INSTRUCTION_GET[] = "get";
 
-const char INSTRUCTION_MPW[] = "mpw";
+const char INSTRUCTION_SAVE[] = "save";
 
 typedef struct {
   char * username;
@@ -41,6 +47,10 @@ static const node_t * lookup(const node_t *p, const char *url){
   return p; // not found
 }
 
+static void node_print(const node_t *p){
+  printf("URL: %s, Username: %s, Password: %s\n",p->url,p->cred.username,p->cred.password);
+}
+
 static node_t *node_new(const char *url, const cred_t cred){
   node_t *new = malloc(sizeof(node_t));
   assert(new != NULL && "new: malloc failed");
@@ -176,10 +186,131 @@ unsigned int tokenise(char *str, char * toks[], unsigned int toksLen){
 /* two extra chars in each line: the newline '\n' and NUL '\0' */
 #define INSTRUCTION_LENGTH (MAX_LINE_LENGTH+2)
 
+/* a global instruction buffer */
 char inst[INSTRUCTION_LENGTH];
 
+/* password mapping for each url: initially empty */
+node_t * map = NULL;
+
+/* a list of node pointers -- the idea is to use these to implement a node
+   stack that we can then use to traverse the tree iteratively, avoiding
+   recursion. We need tree traversal e.g. when saving the passbook to a file */
+typedef struct nodeptr_list {
+  const node_t *p;
+  struct nodeptr_list *next;
+} nodeptr_list_t;
+
+
+nodeptr_list_t * list_push(nodeptr_list_t *lst, const node_t *p){
+  nodeptr_list_t *n = malloc(sizeof(nodeptr_list_t));
+  assert(n != NULL && "push: malloc failed");
+  n->p = p;
+  n->next = lst;
+  return n;
+}
+
+void list_destroy(nodeptr_list_t *lst){
+  while (lst != NULL){
+    nodeptr_list_t *next = lst->next;
+    free(lst);
+    lst = next;
+  }
+}
+
+void list_print(nodeptr_list_t *lst){
+  printf("\nBegin list print:\n");
+  while (lst != NULL){
+    node_print(lst->p);
+    lst = lst->next;
+  }
+  printf("End list print.\n\n");
+}
+
+void print_all(const node_t *p){
+  nodeptr_list_t *lst = NULL;
+  if (p != NULL){
+    lst = list_push(lst,p);
+
+    while(lst != NULL){
+      // keep recursing left until we can go no further
+      while (p->left != NULL){
+        lst = list_push(lst,p->left);
+        p = p->left;
+      }
+      
+      // pop from the stack to simulate the return
+      const node_t *q = lst->p;
+      nodeptr_list_t *temp = lst;
+      lst = lst->next;
+      free(temp);
+
+      // print the node following the return
+      node_print(q);
+
+      // simulate right recursive call
+      if (q->right != NULL){
+        lst = list_push(lst,q->right);
+        p = q->right;
+      }
+    }
+  }
+}
+
+/* returns 0 on successful execution of the instruction in inst */
 static int execute(void){
-  assert(0 && "not implemented yet");
+  char * toks[4]; /* these are pointers to start of different tokens */
+  const unsigned int numToks = tokenise(inst,toks,4);
+  debug_printf("got %u tokens\n",numToks);
+    
+  if (numToks == 0){
+    /* blank line */
+    return 0;
+  }
+    
+  if (numToks < 2){
+    return -1;
+  }
+
+  if (strcmp(toks[0],INSTRUCTION_GET) == 0){
+    if (numToks != 2){
+      return -1;
+    }
+    debug_printf("Looking up: %s\n",toks[1]);
+    const node_t *p = lookup(map,toks[1]);
+    if (p != NULL){
+      node_print(p);
+    }else{
+      printf("Not found.\n");
+    }
+
+  } else if (strcmp(toks[0],INSTRUCTION_REM) == 0){
+    if (numToks != 2){
+      return -1;
+    }
+    debug_printf("Removing: %s\n",toks[1]);
+    map = rem(map,toks[1]);
+    
+  } else if (strcmp(toks[0],INSTRUCTION_PUT) == 0){
+    if (numToks != 4){
+      return -1;
+    }
+    cred_t cred;
+    cred.username = toks[2];
+    cred.password = toks[3];
+    map = put(map,toks[1],cred);
+
+  } else if (strcmp(toks[0],INSTRUCTION_SAVE) == 0){
+    if (numToks != 2){
+      return -1;
+    }
+    debug_printf("Saving to: %s\n",toks[1]);
+    print_all(map);
+    
+  }else{
+    debug_printf("Unrecognised instruction\n");
+    return -1;
+  }
+  
   return 0;
 }
 
@@ -191,6 +322,7 @@ static int run(void){
   
   int instructionCount = 0;
   while (1){
+    memset(inst,0,sizeof(inst));
     char * res = fgets(inst,MAX_LINE_LENGTH+2,f);
     if (res == NULL){
       if (feof(f)){
@@ -223,8 +355,13 @@ static int run(void){
       }
     }
     instructionCount++;
+    int r = execute();
+    if (r != 0){
+      return r;
+    }
   }
-  execute();
+  assert(0 && "Should never reach here");
+  return 0;
 }