snownews/cat.c

// This file is part of Snownews - A lightweight console RSS newsreader
//
// Copyright (c) 2003-2004 Oliver Feiler <kiza@kcore.de>
//
// Snownews is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 3
// as published by the Free Software Foundation.
//
// Snownews is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Snownews. If not, see http://www.gnu.org/licenses/.

#include "main.h"
#include "cat.h"

// Compare global category list with string categoryname and return 1 if a
// matching category was found.
static bool CategoryListItemExists (const char* categoryname)
{
    for (const struct categories * category = _settings.global_categories; category; category = category->next)
	if (strcasecmp (category->name, categoryname) == 0)
	    return true;       // Matching category found.
    return false;
}

// The following functions add items to/delete items from the global category list.
static void CategoryListAddItem (const char* categoryname)
{
    if (CategoryListItemExists (categoryname)) {
	// Only increase refcount
	for (struct categories * category = _settings.global_categories; category; category = category->next)
	    if (strcasecmp (category->name, categoryname) == 0)
		++category->refcount;
    } else {
	// Otherwise add item to structure
	struct categories* category = malloc (sizeof (struct categories));
	category->name = strdup (categoryname);
	category->next = NULL;

	if (!_settings.global_categories) {	// Contains no elements
	    category->next = _settings.global_categories;
	    _settings.global_categories = category;
	} else {
	    bool inserted = false;
	    struct categories* before_ptr = NULL;
	    for (struct categories * new_ptr = _settings.global_categories; new_ptr; new_ptr = new_ptr->next) {
		if (strcasecmp (category->name, new_ptr->name) > 0)
		    before_ptr = new_ptr;	// New category still below current one. Move on.
		else {
		    if (!before_ptr) {	// Insert before _settings.global_categories
			category->next = _settings.global_categories;
			_settings.global_categories = category;
		    } else {   // Insert after category
			before_ptr->next = category;
			category->next = new_ptr;
		    }
		    inserted = true;
		    break;     // Done with this loop.
		}
	    }
	    if (!inserted)     // No match from above. Insert new item at the end of the list.
		before_ptr->next = category;
	}
	// Set refcount to 1 for newly added category.
	category->refcount = 1;
    }
}

// Delete item from category list. Decrease refcount for each deletion.
// If refcount hits 0, remove from list.
static void CategoryListDeleteItem (const char* categoryname)
{
    for (struct categories * category = _settings.global_categories, *before_ptr = NULL; category; category = category->next) {
	if (strcasecmp (category->name, categoryname) == 0) {
	    // Check refcount
	    if (category->refcount > 1) {
		// Still at least one feed defining this category
		--category->refcount;
		break;
	    } else {
		// Last feed using this category removed, kill off the structure
		if (category == _settings.global_categories) {
		    _settings.global_categories = _settings.global_categories->next;
		    free (category->name);
		    free (category);
		    break;
		} else {
		    before_ptr->next = category->next;
		    free (category->name);
		    free (category);
		    break;
		}
	    }
	}
	before_ptr = category;
    }
}

// The following two functions add items to/delete items from a feeds category list.
void FeedCategoryAdd (struct feed* cur_ptr, const char* categoryname)
{
    struct feedcategories* category = malloc (sizeof (struct feedcategories));
    category->name = strdup (categoryname);
    category->next = NULL;

    if (cur_ptr->feedcategories == NULL) {
	// Contains no elements
	category->next = cur_ptr->feedcategories;
	cur_ptr->feedcategories = category;
    } else {
	bool inserted = false;
	struct feedcategories* before_ptr = NULL;
	for (struct feedcategories * new_ptr = cur_ptr->feedcategories; new_ptr != NULL; new_ptr = new_ptr->next) {
	    if (strcasecmp (category->name, new_ptr->name) > 0) {
		// New category still below current one. Move on.
		before_ptr = new_ptr;
	    } else {
		if (before_ptr == NULL) {
		    category->next = cur_ptr->feedcategories;
		    cur_ptr->feedcategories = category;
		} else {
		    // The new category is now > current one. Insert it here.
		    before_ptr->next = category;
		    category->next = new_ptr;
		}
		inserted = true;
		break;	       // Done with this loop.
	    }
	}
	if (!inserted)	       // No match from above. Insert new item at the end of the list.
	    before_ptr->next = category;
    }
    CategoryListAddItem (category->name);
}

void FeedCategoryDelete (struct feed* cur_ptr, const char* categoryname)
{
    // categoryname == category->name which will be freed by this function!
    char* tmpname = strdup (categoryname);
    for (struct feedcategories * category = cur_ptr->feedcategories, *before_ptr = NULL; category; category = category->next) {
	if (strcasecmp (category->name, categoryname) == 0) {
	    if (category == cur_ptr->feedcategories) {
		cur_ptr->feedcategories = cur_ptr->feedcategories->next;
		free (category->name);
		free (category);
		break;
	    } else {
		before_ptr->next = category->next;
		free (category->name);
		free (category);
		break;
	    }
	}
	before_ptr = category;
    }

    // Decrease refcount in global category list.
    CategoryListDeleteItem (tmpname);
    free (tmpname);
}

// Compare a feeds category list with string categoryname.
// Return true if a matching category was found.
bool FeedCategoryExists (const struct feed* cur_ptr, const char* categoryname)
{
    for (const struct feedcategories * category = cur_ptr->feedcategories; category; category = category->next)
	if (strcasecmp (category->name, categoryname) == 0)
	    return true;
    return false;
}

// Return a comma-separated list of categories defined for the provided feed,
// NULL if no category is defined for the feed.
//
// The caller must free the list.
char* GetCategoryList (const struct feed* feed)
{
    if (!feed->feedcategories)
	return NULL;
    char* categories = malloc (1);
    categories[0] = 0;
    size_t len = 1;
    for (const struct feedcategories * category = feed->feedcategories; category; category = category->next) {
	len += strlen (", ") + strlen (category->name);
	categories = realloc (categories, len);
	if (categories[0])
	    strcat (categories, ", ");
	strcat (categories, category->name);
    }
    return categories;
}

// Free and reset the filters list.
void ResetFilters (char** filters)
{
    if (!filters)
	return;
    for (unsigned i = 0; i < 8; ++i) {
	free (filters[i]);
	filters[i] = NULL;
    }
}